Description:TECHNICAL FIELD
The present disclosure relates to a field of sustainable surface coatings. Moreover, the present disclosure relates to a method for synthesizing a fluorine-free superhydrophobic and icephobic coating.
BACKGROUND
Advancements in the field of superhydrophobic and icephobic coatings have gained popularity over the years due to their plethora of applications, such as aircraft de-icing and anti-icing surfaces. The superhydrophobic and icephobic coatings are designed to prevent the formation of ice on various surfaces, particularly in high-altitude environments where ice formation poses a significant problem for aircraft. Traditional methods of combating ice formation involve the use of de-icing fluids or mechanical removal, which can be time-consuming, costly, and energy-intensive. The superhydrophobic coatings rely on the roughness of the structured hierarchy on surface of a substrate combined with low surface energy modification to achieve their water-repellent properties. However, the superhydrophobic modifiers used to reduce surface energy often require dissolution in organic solvents, which are volatile, flammable, and harmful to humans and the environment. Many superhydrophobic modifiers are fluorides, which are expensive and pose irreversible harm to human health and the natural environment. The production and application of fluorinated compounds release perfluorinated alkyl substances (PFAS), which are persistent, bioaccumulative, and potentially hazardous.
Given the growing emphasis on sustainable development and environmental protection, there is an increasing need for substitute for fluorine based coatings. The superhydrophobic coatings must also meet the strict safety requirements for various applications, especially those involving food contact. Such coatings need to tightly bond with various substrates, exhibit good mechanical durability, and provide an environmentally friendly alternative to existing fluorinated superhydrophobic and icephobic coatings. Therefore, there is a need for the development of more environmentally benign and efficient superhydrophobic and icephobic coatings in order to address these challenges and improve the performance of anti-icing technologies.
Therefore, in light of the foregoing discussion, there exists a need to overcome the aforementioned drawbacks.
SUMMARY
The present disclosure provides a method for synthesizing a fluorine-free superhydrophobic and icephobic coating. The present disclosure provides a solution to the technical problem of how to produce a fluorine-free superhydrophobic and icephobic coating using sustainable and environmentally friendly materials. An aim of the present disclosure is to provide a solution that overcomes at least partially the problems encountered in the prior art and provide an improved method that not only synthesizes the fluorine-free superhydrophobic and icephobic coating that is cost-effective but the method that may be easily adopted. Thus, the method of the present disclosure manifests a technical advancement as well as economic benefits.
One or more objectives of the present disclosure is achieved by the solutions provided in the enclosed independent claims. Advantageous implementations of the present disclosure are further defined in the dependent claims.
In one aspect, the present disclosure provides a method for synthesizing a fluorine-free superhydrophobic and icephobic coating. The method includes reacting a transition metal salt and an organic sulphur reagent to form transition metal dichalcogenide nanoflowers. The method further includes treating the transition metal dichalcogenide nanoflowers with ammonia to obtain an alkalized nanoflower solution. Further, the method includes reacting a metallic sulphide salt and a metallic chloride salt to produce metal sulphide nanoparticles. The method further includes combining the alkalized nanoflower solution and the metal sulphide nanoparticles to obtain hybrid nanoparticles. The method further includes applying a polymeric resin coating on a substrate and partially curing the polymeric resin coating. Further, the method includes dispersing the hybrid nanoparticles in a solvent and applying the dispersed hybrid nanoparticles onto the partially cured polymeric resin coating. Furthermore, the method includes fully curing the polymeric resin coating having the hybrid nanoparticles dispersed therein to obtain the fluorine-free superhydrophobic and icephobic coating. The dispersed hybrid nanoparticles have a micro-nano rough surface on the fluorine-free superhydrophobic and icephobic coating having a water contact angle greater than 150 degrees and a water sliding angle less than 10 degrees.
The method of the present disclosure for synthesizing the fluorine-free superhydrophobic and icephobic coating has several significant technical effects. The fluorine-free superhydrophobic coating eliminates the use of fluorine-based compounds, which are known for their environmental persistence and potential toxicity. By using transition metal dichalcogenide nanoflowers and the metal sulphide nanoparticles, the method offers a more sustainable alternative without compromising on performance. The hybrid nanoparticles formed through the combination of the transition metal dichalcogenide nanoflowers and the metal sulphide nanoparticles create a micro-nano rough surface structure on the coating. The unique morphology contributes to the surface achieves a water contact angle greater than 150 degrees, indicating strong water repellency. The specific water contact angle prevents water from adhering to the surface, leading to self-cleaning properties. The micro-nano rough surface also results in the water sliding angle of less than 10 degrees, meaning water droplets easily roll off the surface. The water sliding angle reduces water residue and enhances cleanliness of the coated substrate. The polymeric resin coating applied to the substrate provides mechanical strength and adhesion. The mechanical strength ensures that the superhydrophobic properties are maintained even under mechanical stress or exposure to varying environmental conditions. The method allows flexibility in adjusting the ratio of hybrid nanoparticles to the polymeric resin coating. The versatility enables customization of the coating properties to suit different substrates (such as metals, glass, or polymers) and specific application requirements in various industries. The method involves relatively straightforward process. The scalability makes the method suitable for industrial-scale production, facilitating widespread adoption in manufacturing sectors requiring superhydrophobic surfaces. Depending on the choice of metallic salts used in the method the fluorine-free superhydrophobic coating may exhibit capabilities beyond super hydrophobicity. For instance, photothermal effects can be harnessed for rapid heating and ice prevention, enhancing the utility of the fluorine-free superhydrophobic coating in applications requiring ice phobic surfaces. The polymeric resin ensures strong adhesion of the hybrid nanoparticles to the substrate, even on smooth surfaces such as glass. The compatibility enhances the reliability and longevity of the coating in practical applications. The method of the present disclosure is thus a sustainable approach and has potential to significantly reduce the environmental impact of fluorine. The combination of superhydrophobic and icephobic coatings significantly reduce the energy consumption associated with de-icing procedures, which is particularly beneficial for aircraft and wind turbines that require energy-intensive de-icing methods. The fluorine-free superhydrophobic and icephobic coating also lowers operational costs and downtime by reducing the frequency of maintenance and de-icing operations. Additionally, they extend the lifespan of equipment by minimizing the physical stresses and damage caused by ice accumulation and removal. Environmentally, the fluorine-free superhydrophobic and icephobic coating reduce the reliance on harmful chemical de-icers, thereby decreasing the environmental footprint of de-icing operations. The fluorine-free nature of the fluorine-free superhydrophobic and icephobic coating further broadens their application range, avoiding the environmental and health concerns associated with fluorinated compounds.
In another aspect, the present disclosure provides the fluorine-free superhydrophobic and icephobic coating. The fluorine-free superhydrophobic and icephobic coating includes one part by weight of a polymeric resin coating applied on a substrate one part by weight of hybrid nanoparticles applied on the polymeric resin coating after partial curing. The hybrid nanoparticles comprise metal sulphide nanoparticles deposited on transition metal dichalcogenide nanoflowers. Further, the polymeric resin coating with the hybrid nanoparticles is fully cured to obtain the the fluorine-free superhydrophobic and icephobic coating. Furthermore, the fluorine-free superhydrophobic coating has a water contact angle greater than 150 degrees and a sliding angle less than 10 degrees.
The fluorine-free superhydrophobic and icephobic coating of the present disclosure has same technical effects as described above for the method.
It is to be appreciated that all the aforementioned implementation forms can be combined. All steps which are performed by the various entities described in the present application as well as the functionalities described to be performed by the various entities are intended to mean that the respective entity is adapted to or configured to perform the respective steps and functionalities. It will be appreciated that features of the present disclosure are susceptible to being combined in various combinations without departing from the scope of the present disclosure as defined by the appended claims.
Additional aspects, advantages, features, and objects of the present disclosure would be made apparent from the drawings and the detailed description of the illustrative implementations construed in conjunction with the appended claims that follow.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a flowchart depicting a method for synthesizing a fluorine-free superhydrophobic and icephobic coating, in accordance with an embodiment of the present disclosure;
FIG. 2 is a flowchart for preparing transition metal dichalcogenide nanoflowers, in accordance with an embodiment of the present disclosure;
FIG. 3 is a flowchart for preparing hybrid nanoparticles, in accordance with an embodiment of the present disclosure;
FIG. 4A is a diagram illustrating a scanning electron microscopy (SEM) micrograph of the hybrid nanoparticles, in accordance with an embodiment of present disclosure;
FIG. 4B is a diagram illustrating a magnified scanning electron microscopy (SEM) micrograph of the hybrid nanoparticles, in accordance with an embodiment of present disclosure;
FIG. 5 is a graphical representation illustrating an energy dispersive spectroscopy (EDS) analysis of the hybrid nanoparticles, in accordance with an embodiment of present disclosure; and
FIG. 6 is a diagram illustrating X ray diffraction (XRD) analysis of the hybrid nanoparticles, in accordance with an embodiment of present disclosure.
The summary above, as well as the following detailed description of illustrative embodiments, is better understood when read in conjunction with the appended drawings. For the purpose of illustrating the present disclosure, exemplary constructions of the disclosure are shown in the drawings. However, the present disclosure is not limited to specific methods and instrumentalities disclosed herein. Moreover, those skilled in the art will understand that the drawings are not to scale. Wherever possible, like elements have been indicated by identical numbers.
Embodiments of the present disclosure will now be described, by way of example only, with reference to the following diagrams wherein:
In the accompanying drawings, an underlined number is employed to represent an item over which the underlined number is positioned or an item to which the underlined number is adjacent. A non-underlined number relates to an item identified by a line linking the non-underlined number to the item. When a number is non-underlined and accompanied by an associated arrow, the non-underlined number is used to identify a general item at which the arrow is pointing.
DETAILED DESCRIPTION OF EMBODIMENTS
The following detailed description illustrates embodiments of the present disclosure and ways in which they can be implemented. Although some modes of carrying out the present disclosure have been disclosed, those skilled in the art would recognize that other embodiments for carrying out or practicing the present disclosure are also possible.
FIG. 1 is a flowchart depicting a method for synthesizing a fluorine-free superhydrophobic and icephobic coating, in accordance with an embodiment of the present disclosure. With reference to FIG. 1, there is shown a flowchart of a method 100. In some implementations, the method 100 is executed by a skilled person. The method 100 may include steps 102 to 114.
At step 102, the method 100 includes reacting a transition metal salt and an organic sulphur reagent to form transition metal dichalcogenide nanoflowers. The transition metal dichalcogenide nanoflowers are nanostructures composed of transition metal dichalcogenides, characterized by a flower-like morphology with thin, petal-like nanosheets emanating from a central core. The morphology provides a high surface area and unique properties that enhance their effectiveness in applications such as catalysis, energy storage, sensing, and electronics. An organic sulphur reagent is a chemical compound characterized by the presence of one or more sulphur atoms covalently bonded to carbon atoms within an organic molecule. The organic sulphur reagents helps in introduction of sulphur-containing functional groups into organic compounds. In some implementations, transition metal salt is sodium molybdate dihydrate and the organic sulphur reagent is thiourea. The sodium molybdate dihydrate and the thiourea react efficiently to form molybdenum disulfide nanoflowers with well-defined morphology, promoting high surface area beneficial for catalytic applications, energy storage devices, and sensors. The flower-like structure of the molybdenum disulfide provides more active sites for reactions. Both the molybdenum disulfide and the thiourea are inexpensive and widely available, making the synthesis process cost-effective and scalable for industrial applications. The photothermal properties of the molybdenum disulfide make them suitable for solar energy harvesting, photothermal therapy, and specially de-icing technologies. The molybdenum disulfide is capable of absorbing sunlight across a broad spectrum, particularly in the visible and near-infrared wavelengths. When exposed to sunlight, molybdenum disulfide the present in the fluorine-free superhydrophobic and icephobic coating absorb the light energy and convert it into heat. The heat generation is essential for de-icing applications because it allows the material to raise its surface temperature above the melting point of ice. The absorbed sunlight heats the molybdenum disulfide quickly and uniformly. The rapid heating process ensures that any ice or frost formation on the surface is melted efficiently and swiftly. Additionally, the unique morphology enhances mechanical strength and flexibility, improving material durability.
In an implementation, the reaction of the transition metal salt and the organic sulphur reagent to form the transition metal dichalcogenide nanoflowers includes mixing the transition metal salt and the organic sulphur reagent in a ratio of unity to obtain a first mixture. The transition metal salt and the organic sulphur reagent are weighed out according to the desired 1:1 molar ratio. The weighed amounts of the transition metal salt and the organic sulphur reagent are added to a suitable container. The suitable container may be a beaker or a reaction vessel depending on the scale of synthesis. During mixing, temperature is maintained at a level that ensures solubility and stability of the reactants (i.e., the transition metal salt and the organic sulphur reagent), Typically, room temperature to slightly elevated temperatures may be used depending on the reactants. Advantageously, mixing in the unity molar ratio ensures that the reactants are present in stoichiometric proportions. This minimizes the presence of unreacted starting materials, enhancing the efficiency of the reaction.
The equal molar ratio of the transition metal salt and the organic sulphur reagent maximizes the yield of the transition metal dichalcogenide nanoflowers. This approach prevents excess of either reactant, which could otherwise lead to unwanted by-products or incomplete conversion. The unity molar ratio may influence the morphology and size distribution of the resulting the transition metal dichalcogenide nanoflowers. The simplicity and effectiveness of mixing in the unity molar ratio make the method scalable for industrial production. It allows for consistent batch-to-batch synthesis with predictable outcomes, essential for large-scale manufacturing.
In an implementation, the reaction of the transition metal salt and the organic sulphur reagent to form the transition metal dichalcogenide nanoflowers further includes adding the first mixture to a solution of deionised water and ethanol to obtain a first solution and performing sonication on the first solution to obtain a second solution. The deionized water is water that has had most of its mineral ions removed, such as cations like sodium, calcium, iron, and copper, and anions such as chloride and sulphate. The deionized water is used to avoid any potential contamination from impurities that could interfere with the reaction. The ethanol is a common organic solvent. The ethanol is used to help lower the surface tension of the deionised water, improve wetting properties, and aid in the dispersion of reactants. The ethanol also helps in achieving a better mixing of hydrophobic and hydrophilic substances. The specific ratio of deionized water to ethanol can vary depending on the exact requirements of the reaction is taken. The deionized water is poured into a clean container, followed by the measured ethanol. The solution of the deionised water and the ethanol is gently stirred to ensure thorough mixing. The stirring may be done manually with a stirrer or using a magnetic stirrer for better consistency.
Further, the first mixture is slowly added to the prepared solution of the deionized water and the ethanol. The addition should be gradual to prevent clumping and ensure complete dissolution. Any suitable agitation method may be used to continuously stir the solution of the deionized water and the ethanol as the first mixture is added. The constant stirring promotes uniform dispersion and prevents the formation of agglomerates. As a result, the first solution is obtained. Furthermore, the container with the first solution is placed into an ultrasonic bath for the sonication. The sonication is a process in which high-frequency sound waves (i.e. above 20 kHz), are used to agitate materials. The sonication involves the application of ultrasonic waves generated by a transducer that converts electrical energy into mechanical vibrations in a liquid medium. The sonication is performed by a sonicator. The sonicator emits high-frequency sound waves that create cavitation bubbles in the liquid. The cavitation process helps in breaking down any agglomerates and ensures a uniform dispersion of the reactants at the molecular level. In some implementations, the sonication on the first solution is performed for 28 min to 32 mins. The specific time period optimises the balance between effective dispersion, controlled energy input, and maintaining the integrity of the reactants. Further, the specific time period ensures that the solution is thoroughly mixed, and the particles are well-dispersed, which are critical for the successful formation of transition metal dichalcogenide nanoflowers. It prevents overheating, avoids particle agglomeration, and ensures consistent, reproducible results, making the process efficient and reliable for producing high-quality fluorine-free superhydrophobic and icephobic coatings.
In an implementation, the reaction of the transition metal salt and the organic sulphur reagent to form the transition metal dichalcogenide nanoflowers further includes placing the second solution in a Teflon lined autoclave and heating the second solution for 22 to 26 hours at a temperature ranging from 180 to 220 degrees Celsius to obtain a heated solution. The second solution is placed in the Teflon lined autoclave and suitable for high-temperature operations. The Teflon lined autoclave is typically made of materials resistant to high temperatures and chemical corrosion. To prevent evaporation and maintain a controlled environment, the Teflon lined autoclave is securely sealed. This ensures that the pressure and temperature inside the Teflon lined autoclave remain constant throughout the heating process. The second solution is heated for 22 to 26 hours. The prolonged heating period is important for allowing sufficient time for the nucleation and growth of the transition metal dichalcogenide nanoflowers. During nucleation phase, initial formation of small clusters or nuclei of the transition metal dichalcogenide. During growth phase, expansion and growth of these nuclei into complete transition metal dichalcogenide nanoflower structures takes place. Continuous monitoring of the temperature is essential. This can be achieved using thermocouples or other temperature sensors to ensure the temperature remains within the specified range. In Teflon lined autoclave, pressure monitoring is also important to prevent over-pressurization, which can be dangerous. Pressure relief valves or controlled venting systems can be used to manage pressure levels. The heating is performed at a temperature range of 180 to 220 degrees Celsius. This range is chosen based on the thermal stability and reactivity of the transition metal salt and the organic sulphur reagent. The solution is heated for 22 to 26 hours. This prolonged heating period is crucial for allowing sufficient time for the nucleation and growth of the transition metal dichalcogenide nanoflowers. The transition metal dichalcogenide nanoflowers are produced within the heated solution and the heated solution is further treated to obtain the transition metal dichalcogenide nanoflowers.
In an implementation, the reaction of the transition metal salt and the organic sulphur reagent to form the transition metal dichalcogenide nanoflowers further includes centrifuging, washing and drying the heated solution to obtain the transition metal dichalcogenide nanoflowers. The heated solution is transferred into centrifuge tubes. The centrifuge tubes are balanced to prevent vibrations during centrifugation. The centrifuge tubes are sealed securely to avoid spillage during high-speed rotation. and kept in the centrifuge rotor. The centrifuge rotor is spun at a high speed (for example, depending on the equipment and desired separation efficiency). Centrifugation causes the denser transition metal dichalcogenide nanoflowers to sediment at the bottom of the centrifuge tube, separating them from the supernatant (liquid above the transition metal dichalcogenide nanoflowers). The supernatant is removed without disturbing the sedimented transition metal dichalcogenide nanoflowers.
Washing is essential to remove residual reactants, by-products, and impurities that may remain after centrifugation. It helps in obtaining purified transition metal dichalcogenide nanoflowers. A wash solvent (for example, deionized water or ethanol) to the centrifuge tube containing the sedimented transition metal dichalcogenide nanoflowers. The volume of the wash solvent is made adequate to cover the transition metal dichalcogenide nanoflowers. The centrifuge tube is swirled to resuspend the transition metal dichalcogenide nanoflowers in the wash solvent. The transition metal dichalcogenide nanoflowers are allowed to settle again by gravity or perform a brief low-speed centrifugation if necessary. The wash solvent is carefully removed without disturbing the transition metal dichalcogenide nanoflowers. In an implementation, drying is carried out to remove the wash solvent completely from the transition metal dichalcogenide nanoflowers, leaving them in a dry, solid state suitable for further processing or storage. The drying process is closely monitored to prevent overheating or agglomeration of the transition metal dichalcogenide nanoflowers.
At step 104, the method 100 further includes, treating the transition metal dichalcogenide nanoflowers with ammonia to obtain an alkalized nanoflower solution. The transition metal dichalcogenide nanoflowers are typically immersed in the ammonia solution. The concentration and duration of exposure can vary based on the specific synthesis conditions. The ammonia acts as a base in this process, reacting with any acidic components or residual impurities present on the surface of the transition metal dichalcogenide nanoflowers. Upon treatment with ammonia, the surface of the transition metal dichalcogenide nanoflowers becomes alkalized. This results in the formation of an alkalized nanoflower solution, where the nanoflowers are dispersed in a medium that has a slightly basic pH due to the presence of the ammonia. Treatment with the ammonia effectively removes residual impurities, adsorbed species, or acidic residues from the surface of the transition metal dichalcogenide nanoflowers. This cleaning process enhances the purity and cleanliness of the transition metal dichalcogenide nanoflowers, which is crucial for subsequent functionalization and coating processes. The alkalization of the transition metal dichalcogenide nanoflowers via ammonia treatment alters the surface chemistry, making it more hydrophilic. This controlled surface modification can facilitate better adhesion of subsequent coating materials. Further, treatment with the ammonia can stabilize the morphology and structure of the transition metal dichalcogenide nanoflowers by preventing aggregation or agglomeration. This ensures that the transition metal dichalcogenide nanoflowers retain their flower-like morphology and high surface area, which are critical for achieving superhydrophobic properties. The alkalized nanoflower solution serves as an ideal substrate for further processing of, such as introducing hydrophobic modifiers or coupling agents. This versatility allows for tailoring the surface properties of the transition metal dichalcogenide nanoflowers to achieve specific hydrophobic characteristics required for the fluorine free superhydrophobic and icephobic coatings.
At step 106, the method 100 further includes reacting a metallic sulphide salt and a metallic chloride salt to produce metal sulphide nanoparticles. The metallic sulphide salt and the metallic chloride salt are dissolved in a suitable solvent to form different homogeneous solution. In an example, solvent may be a deionized water, the metallic sulphide salt is dissolved in the deionized water to form a first homogeneous solution and the metallic chloride salt is dissolved in the deionized water to form a second homogeneous solution. Further, the first homogeneous solution is gradually added to the and the second homogeneous solution while stirring continuously. The mixing initiates a chemical reaction between the metallic ions from the chloride salt and the sulphide ions from the sulphide salt. The reaction between the metallic sulphide present in the first homogeneous solution and metallic chloride salts present in the second homogeneous solution results in the formation of the metal sulphide nanoparticles. For example, if copper chloride and sodium sulphide are used, the reaction produces copper sulphide nanoparticles. The reaction between the metallic sulphide present in the first homogeneous solution and metallic chloride salts present in the second homogeneous solution is carried out under controlled conditions of temperature and pH to ensure the formation of uniform and well-defined metal sulphide nanoparticles. The conditions can vary depending on the specific salts used and the desired properties of the metal sulphide nanoparticles. The reaction is often performed at room temperature or slightly elevated temperatures to facilitate the reaction kinetics. The pH of the reaction mixture may be adjusted to optimize the formation and stability of the metal sulphide nanoparticles. In some implementations, metal sulphide nanoparticles comprise at least one of copper sulphide (CuS), tungsten disulphide (WS2), iron sulphide (FeS), nickel sulphide (NiS), and silver sulphide (Ag2S). In some examples, the hybrid nanoparticles may include the copper sulphide and the transition metal dichalcogenide nanoflowers. In some other examples, the hybrid nanoparticles may include the tungsten disulphide and the transition metal dichalcogenide nanoflowers. In yet another example, the hybrid nanoparticles may include the iron sulphide and the transition metal dichalcogenide nanoflowers. Further, in some other examples, the hybrid nanoparticles may include the iron sulphide and the transition metal dichalcogenide nanoflowers. In yet other example, the hybrid nanoparticles may include silver disulphide and the transition metal dichalcogenide nanoflowers.
At step 108, the method 100 further includes combining the alkalized nanoflower solution and the metal sulphide nanoparticles to obtain hybrid nanoparticles. Specifically in some implementations, combining of the alkalized nanoflower solution and the metal sulphide nanoparticles to obtain the hybrid nanoparticles includes mixing and heating the alkalized nanoflower solution and the metal sulphide nanoparticles for 56 to 64 minutes to obtain a synthesis solution The mixing the alkalized nanoflower solution with the prepared metal sulphide nanoparticles. This mixing process aims to bring together the two components in a homogeneous solution. The mixing is carried out in a suitable solvent, often deionized water or ethanol, which helps in dispersing both the nanoflowers and the nanoparticles uniformly. The choice of solvent depends on the compatibility with the nanoparticles and the stability of the nanoflower dispersion. Thorough mixing is essential to ensure that the alkalized nanoflowers and metal sulphide nanoparticles interact effectively. The homogenization facilitates the contact between the reactive sites on the transition metal dichalcogenide nanoflower surfaces (e.g., hydroxyl groups from alkalization) and the metal ions of the metal sulphide nanoparticles. Once mixed, the synthesis solution is heated for 56 to 64 minutes allow for the interaction between the alkalized nanoflowers and the metal sulphide nanoparticles. The heating is crucial for the formation of hybrid structures where the nanoparticles are anchored or deposited onto the nanoflower surfaces. During heating, chemical bonds may form between the functional groups on the nanoflower surfaces (such as hydroxyl or amino groups) and the metal ions or nanoparticles. The interactions contribute to the formation of hybrid nanoparticles with combined properties from both components. Combining the transition metal dichalcogenide nanoflowers with the metal sulphide nanoparticles creates hybrid structures that possess the unique properties. The synergy of combining the transition metal dichalcogenide nanoflowers with the metal sulphide nanoparticles may enhance the material’s overall performance of the hybrid nanoparticles. The hybrid nanoparticles have a high surface area due to the flower-like morphology of the transition metal dichalcogenide nanoflowers and the small size of the metal sulphide nanoparticles. The high surface area provides more active sites for chemical reactions, improving the efficiency of the hybrid nanoparticles.
In an implementation, combining of the alkalized nanoflower solution and the metal sulphide nanoparticles to obtain the hybrid nanoparticles further includes filtering the synthesis solution using a high-density polymer membrane and washing the filtrate with water and ethanol. Filtration is employed to separate the hybrid nanoparticles from the synthesis solution containing unreacted starting materials, by-products, and solvent. The high-density polymer membrane is selected for filtration. The high-density polymer membrane is a porous material composed of polymers like high-density polyethylene (HDPE), characterized by a dense molecular structure and a density typically ranging from 0.93 to 0.97 grams per cubic centimetre. The high-density polymer membranes are essential in applications needing strong mechanical strength, chemical resistance, and controlled porosity. The high-density polymer membrane play a role in filtration, separation processes, and membrane technologies by effectively filtering solutions and segregating substances based on size or molecular weight, owing to their durable construction and precise pore size distribution The high-density polymer membrane is preferred because it offers precise control over particle size separation and has good chemical compatibility with aqueous and organic solvents commonly used in nanoparticle synthesis. The membrane pore size is chosen based on the desired size range of the hybrid nanoparticles. Typically, high-density polymer membranes with pore sizes in the range of tens to hundreds of nanometres are suitable for filtering nanoparticles. The synthesis solution, containing the mixed alkalized nanoflower solution and metal sulphide nanoparticles, is poured or transferred onto the high-density polymer membrane. Further, vacuum is applied to facilitate the filtration process. This helps in driving the solution through the membrane pores while retaining the hybrid nanoparticles on the membrane surface. The hybrid nanoparticles are retained on the high-density polymer membrane surface due to their larger size compared to the pore size of the high-density polymer membrane. The high-density polymer membrane effectively separates the hybrid nanoparticles from smaller molecules, ions, and solvent molecules present in the filtrate. After filtration, the retained hybrid nanoparticles on the membrane need to be washed to remove residual impurities and traces of solvent. Washing ensures the purity of the hybrid nanoparticles and removes any loosely bound or unreacted components that may affect their properties and performance in subsequent applications. The hybrid nanoparticles on the membrane are first washed with deionized or distilled water. Water is effective in removing water-soluble impurities such as salts, excess reactants, and small organic molecules. The washing process may involve gently pouring or spraying water onto the membrane surface where the nanoparticles are retained. The water wash is repeated multiple times to ensure thorough removal of water-soluble contaminants. Following the water wash, the hybrid nanoparticles undergo a subsequent wash with ethanol. Ethanol helps to remove organic contaminants, residual solvent, and other hydrophobic impurities that may still be present after the water wash. Similar to the water wash, ethanol is gently applied to the membrane surface to wash the nanoparticles, ensuring comprehensive cleaning.
In an implementation, combining of the alkalized nanoflower solution and the metal sulphide nanoparticles to obtain the hybrid nanoparticles further includes drying and powdering the washed filtrate to obtain the hybrid nanoparticles. After washing with water and ethanol, the high-density polymer membrane with the washed hybrid nanoparticles is typically allowed to air dry under controlled conditions. Further, in order to avoid agglomeration or damage to the hybrid nanoparticles during drying, which could affect their dispersibility and performance. Once dried, the hybrid nanoparticles can be carefully collected from the membrane surface using appropriate techniques, such as scraping or dissolving the nanoparticles off the high-density polymer membrane. Filtration followed by washing with water and ethanol ensures the purity of the hybrid nanoparticles by removing impurities and excess reactants. The purification contributes to the consistency and reproducibility of the properties of the hybrid nanoparticles. The use of water and ethanol as washing solvents is environmentally friendly compared to other harsh chemicals, minimizing the environmental impact of the synthesis process. The filtration and washing process may be scaled up for industrial production, maintaining efficiency and cost-effectiveness in large-scale nanoparticle synthesis. In some implementations, the combining of the alkalized nanoflower solution and the metal sulphide nanoparticles to obtain the hybrid nanoparticles is carried out via a sol-gel method. The sol-gel method facilitates uniform mixing at nanoscale level, ensuring a consistent distribution of the metal sulphide nanoparticles within the nanoflower matrix. Improved interaction between the nanoflowers and the metal sulphide nanoparticles leads to more uniform hybrid nanoparticles.
The sol-gel method allows precise control over the reaction parameters (such as pH, temperature, and concentration), enabling the synthesis of nanoparticles with desired size, shape, and morphology. This control helps tailor the properties of the hybrid nanoparticles for specific applications, such as enhanced mechanical strength or improved catalytic activity. The controlled environment reduces the risk of contamination, ensuring the purity of the final product. The sol-gel method is compatible with a wide range of materials, allowing the incorporation of different metal sulphides and nanoflower types to create the hybrid nanoparticles. The resulting hybrid nanoparticles can be used in diverse applications, from coatings and sensors to catalysis and energy storage. The sol-gel method can be easily scaled up for industrial production, making it suitable for both laboratory-scale and commercial-scale synthesis. The combination of nanoflowers and metal sulphide nanoparticles can result in synergistic properties, such as increased surface area, enhanced photothermal effects, and superior electrical conductivity. The sol-gel method may be carried out under mild conditions and with environmentally benign solvents, reducing the overall environmental impact. The sol-gel method generally requires lower energy input compared to other high-temperature synthesis techniques, making it more sustainable. The sol-gel method allows for the control of pore size and distribution within the hybrid nanoparticles, which is beneficial for applications like catalysis and drug delivery where specific pore characteristics are required.
At step 110, the method 100 further includes applying a polymeric resin coating on a substrate and partially curing the polymeric resin coating. The polymeric resin may be interchangeably called as an epoxy. The polymeric resin refers to a combination of an epoxy resin and a hardener. In an example, the epoxy resin may be ether based and the hardener may be an amine based. The epoxy resin and the hardener are thoroughly mixed in a clean, dry container using a stirring tool (for e.g., mechanical stirrer). The stirring must ensure that the mixture of the epoxy resin and the hardener is homogenous and free of air bubbles. In an example, stirring may be performed for at least 2-3 minutes, scraping the sides and bottom of the container to ensure complete mixing.
In some implementations, the substrates may be a glass, FRP (Fiberglass Reinforced Plastic), aluminium, brass. In an example, the glass slide is used as substrate. A pipette or dropper may be used to drop epoxy onto the surface of the glass slide. The epoxy is uniformly spread across the surface of the glass slide. The coated glass slide is placed on a flat, level surface in a room-temperature environment approximately 20-25°C. The epoxy-coated slide is left undisturbed for 13-17 minutes. The time frame is important for the epoxy to reach a gel-like, semi-cured state. The exact timing may vary slightly based on ambient temperature and humidity. The coated slide is periodically checked to monitor the curing progress. The epoxy should transition from a liquid to a gel-like state during this period. The semi-cured state is achieved when the epoxy is no longer runny but still supple to the touch.
At step 112, the method 100 further includes dispersing the hybrid nanoparticles in a solvent and applying the dispersed hybrid nanoparticles onto the partially cured polymeric resin coating. The dispersion of hybrid nanoparticles may be prepared using any solvent compatible with the hybrid nanoparticles. In an example, the solvent may be acetone. The required amount of hybrid nanoparticles is weighed accurately based on the desired concentration in the final dispersion. This may done using a balance to ensure precision. The weighed hybrid nanoparticles are then added to a suitable volume of the acetone in a container. The ratio of nanoparticles to acetone is determined based on the desired concentration and the application method (e.g., spray coating, dip coating). To achieve uniform dispersion, the mixture of the hybrid nanoparticles and the acetone undergoes vigorous mixing. Once the dispersion is prepared, it is applied onto the partially cured epoxy resin coating. In an example, the techniques like spray coating may be used, the dispersion is loaded into a spray gun and applied at low pressure. The spray process ensures even coverage of the hybrid nanoparticles onto the substrate. The solvent (in this example, acetone) aids in the dispersion and application process by wetting the surface of the partially cured resin and enabling the hybrid nanoparticles to embed effectively before the epoxy fully cures. The solvent (in this example, acetone) evaporates quickly after application, leaving behind a homogeneous layer of the hybrid nanoparticles embedded within the epoxy resin matrix.
In an implementation, the method 100 further includes selecting a ratio by weight of the hybrid nanoparticles to the polymeric resin coating the amount of hybrid nanoparticles on the surface of the fluorine-free superhydrophobic and icephobic coating. The ratio determines the concentration of the hybrid nanoparticles dispersed within the resin matrix. The hybrid nanoparticles contribute to creating a rough surface structure at the micro and nano scales. The roughness is essential for achieving superhydrophobic properties by creating air pockets and reducing the contact area between water droplets and the surface of the substrate. By carefully adjusting the hybrid nanoparticle-to-polymeric resin ratio, the surface roughness can be optimized to maximize the Cassie-Baxter state, where water droplets sit atop air pockets on the surface rather than wetting it. This results in superior water repellency and self-cleaning properties, essential for applications requiring durable and low-maintenance surfaces. Incorporating the hybrid nanoparticles into the polymeric resin coating not only modifies surface roughness but also enhances mechanical properties such as hardness, scratch resistance, and durability. The hybrid nanoparticle concentration influences the surface energy of the polymeric coating. By adjusting the ratio, it is possible to tailor the surface energy to achieve specific functionalities, such as anti-fouling or anti-icing properties, in addition to super hydrophobicity. Utilizing a fluorine-free approach reduces environmental impact and health concerns associated with traditional hydrophobic coatings containing fluorinated compounds. The hybrid nanoparticle provides comparable or superior performance without the environmental drawbacks. The method allows for flexibility in coating formulation, making it adaptable to various substrates and application methods.
In an implementation, the fluorine-free superhydrophobic and icephobic coating comprises the hybrid nanoparticles and the polymeric resin coating applied on the substrate in the ratio by weight of 1:1. The polymeric resin ensures strong adhesion of the coating to the substrate, while the nanoparticles provide the desired surface properties. A 1:1 ratio optimizes both adhesion and surface functionality. The ratio facilitates an even and manageable application process, whether using spray coating or other methods, leading to reproducible and reliable coating performance. The combination of nanoparticles and resin at this ratio offers enhanced resistance to chemical, UV, and environmental degradation, extending the lifespan of the coating.
In an implementation, when the ratio by weight of the hybrid nanoparticles to the polymeric coating applied on the substrate is 1:1, the fluorine-free superhydrophobic and icephobic coating has the water contact angle of 156.68 degrees. A water contact angle of 156.68 degrees indicates a highly hydrophobic surface, where water droplets form almost spherical shapes and roll off easily. The superhydrophobicity is vital for applications where water repellency is essential. Further, the high contact angle is indicative of a lotus effect, where water droplets pick up dirt and debris as they roll off the surface, keeping the surface clean. The self-cleaning property reduces the need for frequent maintenance. Surfaces with such high contact angles are less likely to allow the formation of ice and biofilms. This makes the coating suitable for applications in cold environments and marine settings, where ice formation and fouling can be problematic. The high contact angle minimizes the interaction between the liquid and the surface, which is beneficial for applications requiring reduced wettability, such as in protective coatings for aircraft, electronics, textiles, and automotive parts.
At step 114, the method 100 further includes fully curing the polymeric resin coating, having the hybrid nanoparticles dispersed therein to obtain the fluorine-free superhydrophobic and icephobic coating. The dispersed hybrid nanoparticles have a micro-nano rough surface on the fluorine-free superhydrophobic and icephobic coating, having a water contact angle greater than 150 degrees and a water sliding angle less than 10 degrees. The polymeric resin coating is fully cured by subjecting it to elevated temperatures (for example, overnight at 80 °C). During the curing process, the polymeric resin coating undergoes cross-linking, forming a durable and solid matrix that encapsulates the hybrid nanoparticles. The incorporation of hybrid nanoparticles into the resin matrix improves the mechanical strength, hardness, and abrasion resistance of the coating. The hybrid nanoparticles enhance the adhesion of the coating to the substrate, reducing the risk of delamination or peeling. The hybrid nanoparticles modify the surface properties of the coating, such as hydrophobicity, surface roughness, or conductivity, depending on the type of nanoparticles used. The hybrid nanoparticles can impart chemical resistance to the coating, protecting the substrate from corrosion or chemical degradation. By controlling the type, size, and concentration of the hybrid nanoparticles dispersed in the polymeric resin, specific functional properties such as electrical conductivity, thermal stability, or optical properties can be tailored for various applications.
The water contact angle is defined as the angle formed at the junction where a water droplet meets the substrate coated with the fluorine-free superhydrophobic and icephobic coating. The angle is measured between the tangent to the water droplet at the point of contact and the plane of the coated surface. The sliding angle is the angle at which a water droplet placed on the superhydrophobic surface starts to move or slide due to the force of gravity. It is typically measured by tilting the surface until the droplet begins to move. A lower sliding angle indicates that the surface has excellent water-repellent properties, as the droplet slides off more easily. The water contact greater than 150 degrees indicates that water droplets on the surface bead up tightly, minimizing contact area with the coating and thus exhibiting high repellence, and the sliding angle less than 10 degrees means that water droplets slide off the surface very easily under the influence of gravity, demonstrating excellent self-cleaning and anti-wetting characteristics. The combination of the micro-nano rough surface structure provided by the hybrid nanoparticles and the fully cured polymeric resin results in a robust fluorine-free superhydrophobic and icephobic coating. This coating is effective in repelling water, resisting wetting, and maintaining cleanliness due to its low sliding angle and high water contact angle.
The fluorine-free superhydrophobic and icephobic coating prevents both water and ice from adhering to surfaces. Water droplets bead up and roll off due to the superhydrophobic nature, while ice formation is minimized or prevented by the icephobic properties. The superhydrophobic surface ensures that dirt and other particles are easily removed by water droplets. This self-cleaning effect extends to ice, where the icephobic nature ensures that ice does not bond strongly to the surface, allowing it to be easily removed. Surfaces coated with the combined superhydrophobic and icephobic material require less frequent cleaning and de-icing. This leads to lower operational costs and reduced downtime for maintenance, making it highly efficient for various applications. By preventing ice formation and enabling easy ice removal, the coating reduces the need for energy-intensive de-icing procedures. This is particularly beneficial for applications such as aircraft, wind turbines, and other equipment exposed to cold environments. In dynamic systems like wind turbines and aircraft, maintaining an ice-free surface ensures optimal performance. This leads to increased efficiency, reliability, and safety. The reduction in ice formation and water accumulation helps in minimizing physical stress and potential damage to the equipment. This prolongs the lifespan of materials and surfaces, reducing the need for frequent replacements. The fluorine-free superhydrophobic and icephobic coating reduces the need for chemical de-icers, which are often harmful to the environment. This decreases the environmental impact of de-icing operations and contributes to more sustainable practices. The fluorine-free superhydrophobic and icephobic coating is suitable for a wide range of applications without the environmental and health concerns associated with fluorinated compounds. Its effectiveness in various environments makes it a versatile solution for both industrial and consumer applications.
FIG. 2 depict a flowchart for preparing transition metal dichalcogenide nanoflowers, in accordance with an embodiment of the present disclosure. FIG. 2 is described in conjunction with FIG. 1. With reference to FIG. 2, there is shown a flowchart 200 that includes a series of operations from 202 to 206.
At operation 202, the transition metal salt and the organic sulphur reagent are mixed to obtain a mixture. In an example, the transition metal salt and the organic sulphur reagent are sodium molybdate dihydrate and thiourea respectively. The sodium molybdate dihydrate and thiourea are dissolved in a solution of the deionized water and ethanol to obtain a solution. The solution so obtained is underwent sonication for about 28 to 32 minutes. This time frame is optimized to ensure thorough mixing and dispersion of the sodium molybdate dihydrate and the thiourea within the solvent. It allows sufficient time for the ultrasonic waves to break down any agglomerates, promote uniform distribution of reactants, and initiate the nucleation of the transition metal dichalcogenide nanoflowers.
At operation 204, the solution obtained at operation 202 is heated for a certain temperature range. In an example, the solution is transferred to Teflon-lined autoclave and heated at 180-220°C for 22-26 hours. The solution obtained from operation 202 is carefully transferred into the Teflon-lined autoclave. The transfer of the solution is done under controlled conditions to prevent contamination and ensure safety, as the substances involved may be reactive. The solution is heated at a temperature range of 180-220°C. The temperature range is chosen based on the specific chemical reactions and processes that need to occur within the solution. The heating process is maintained for 22-26 hours, and a heated mixture is obtained.
At operation 206, the heated solution is treated. The extended duration heating at operation 204 allows for complete reaction and transformation of the components within the heated solution. Heating at 180-220°C promotes the nucleation and growth of the transition metal dichalcogenide nanoflowers, within the heated solution. The specific temperature range ensures that the crystallization process is controlled and consistent. The Teflon-lined autoclave, when heated, also increases the internal pressure. The pressure, combined with the high temperature, creates unique conditions that can enhance reaction rates and yield high-purity products with well-defined crystal structures within the heated solution. The heated solution is further underwent centrifugation. The centrifuge tubes containing the heated solution are placed in the centrifuge machine. In an example, the centrifuge machine is set to spin at a high speed, at around 10,000 to 15,000 RPM (revolutions per minute), for 10-30 minutes. It is to be noted the exact speed and duration depend on the specific density and size of the transition metal dichalcogenide nanoflowers being separated. During centrifugation, the centrifugal force causes the heavier transition metal dichalcogenide nanoflowers to sediment at the bottom of the centrifuge tubes, while the lighter supernatant (i.e., liquid portion of the heated solution) remains on top. After centrifugation, the supernatant is carefully decanted or removed using a pipette, leaving behind the sedimented transition metal dichalcogenide nanoflowers at the bottom of the centrifuge tubes. To ensure purity, the transition metal dichalcogenide nanoflowers are washed with deionized water or ethanol. The washing helps remove any remaining impurities or unreacted substances. The washed transition metal dichalcogenide nanoflowers are then dried (for example, in an oven or under vacuum) to remove any residual solvent, resulting in dry, pure transition metal dichalcogenide nanoflowers.
FIG. 3 is a flowchart for synthesis hybrid nanoparticles, in accordance with an embodiment of the present disclosure. FIG. 3 is described in conjunction with FIG. 1 and 2. With reference to FIG. 3, there is shown a flowchart 300 that includes a series of operations from 302 to 310.
At operation 302, the transition metal dichalcogenide nanoflowers are dispersed in the secondary alcohol to obtain a dispersion of metal dichalcogenide nanoflowers. In an example, the transition metal dichalcogenide nanoflowers are molybdenum disulfide particles, and the secondary alcohol is isopropyl alcohol (IPA). In the given example, before dispersion, the required amount of the molybdenum disulfide particles are accurately measured. The required amount of the molybdenum disulfide particles depends on the desired concentration of the dispersion of the molybdenum disulfide particles. Further, the weighed molybdenum disulfide particles are transferred into the measured IPA in a clean glass beaker. An initial combination the molybdenum disulfide particles and the IPA allows the molybdenum disulfide particles to start wetting and dispersing in the solvent. A glass stirring rod to gently mix the molybdenum disulfide particles with the IPA. The stirring helps to begin the dispersion process and ensures that the molybdenum disulfide particles are evenly distributed in the solvent. The probe sonication is performed for 13 to 17 minutes on the combination of the molybdenum disulfide particles and the IPA. The ultrasonic waves generated by the sonicator create cavitation bubbles in the IPA, which collapse and produce intense local energy. The intense local energy helps to break apart agglomerates of the molybdenum disulfide particles and achieve a uniform dispersion. During sonication, the temperature of the dispersion is monitored. The IPA is flammable, and excessive heating should be avoided. The mixture during sonication to ensure that the molybdenum disulfide particles are being effectively dispersed. As a result, the dispersion of metal dichalcogenide nanoflowers is obtained.
At operation 304, the ammonia is added to the dispersion of metal dichalcogenide nanoflowers to obtain the alkalized nanoflower solution. In operation, under continuous magnetic stirring, the ammonia solution is added dropwise to the dispersion of metal dichalcogenide nanoflower. The dropwise addition is slow and controlled to prevent localized pH spikes and ensure uniform distribution of the ammonia throughout the dispersion of metal dichalcogenide nanoflower. The pH of the dispersion of metal dichalcogenide nanoflower is continuously monitored using a pH meter. The addition of ammonia is continued until the pH meter indicates that the pH has reached the desired level. The process might take several minutes, depending on the volume of the dispersion of metal dichalcogenide nanoflower and the initial pH. The magnetic stirring throughout the process ensures that the ammonia is evenly distributed within the dispersion of metal dichalcogenide nanoflower. Once the desired pH is reached, stirring for an additional 10-15 minutes is done to ensure complete reaction and stabilization of the dispersion of metal dichalcogenide nanoflower and as the pH is increased to desired level the alkalized nanoflower solution is obtained.
At operation 306, the metallic sulphide salt solution is prepared and added to the alkalized nanoflower solution. Initially, the metallic sulphide salt is dispersed in the deionized water. The solution of the metallic sulphide salt and the deionized water is stirred (for example, using a magnetic stirrer or any other suitable agitation method). The stirring ensures thorough mixing and dissolution or dispersion of the metallic sulphide salt in the deionized water, and as a result, the metallic sulphide salt solution is obtained. Further, the obtained the metallic sulphide salt solution is obtained to the alkalized nanoflower solution dropwise under magnetic stirring for 8 to 12 minutes. The addition of the metallic sulphide salt solution to the alkalized nanoflower solution results in the formation of a pre-hybrid solution.
At operation 308, the metallic chloride salt solution is prepared and added to the pre-hybrid solution. Initially, the metallic chloride salt is dispersed in the deionized water. The mixture of the metallic chloride salt and the deionized water is stirred with a suitable agitation method. The stirring ensures thorough mixing and dissolution or dispersion of the metallic chloride salt solution. Further, the metallic chloride salt solution is added drop wise to the pre-hybrid solution to produce a hybrid solution. Adding the metallic chloride salt solution dropwise allows for precise control over the rate at which the metallic chloride salt reacts with other components in the pre-hybrid solution. By adding the metallic chloride salt solution dropwise, the contact area between reactants (i.e. the metallic chloride salt solution and the pre-hybrid solution) is controlled, reducing the likelihood of side reactions or the formation of undesired compounds. This enhances the purity and yield of the desired product. Further, the dropwise addition prevents sudden spikes in temperature, which could affect reaction kinetics and product quality.
At operation 310, the hybrid solution obtained at operation 308 is utilized to produce the hybrid nanoparticles. The hybrid solution is stirred for about 1-3 hours, and after stirring, the hybrid solution is filtered using the high-density polymer membrane (for example, polyvinylidene difluoride membrane). In an example, a filtration apparatus is set up, which may include a filtration funnel or holder designed to fit the PVDF membrane. The PVDF membrane in the filtration apparatus. The stirred hybrid solution is poured into the filtration apparatus containing the PVDF membrane. Depending on the filtration apparatus setup, gentle vacuum suction is applied to the filtration system. The vacuum suction helps to accelerate the filtration process by drawing the liquid phase (i.e., solvent) through the PVDF membrane pores while leaving behind the solid particles (i.e., hybrid nanoparticles) on the PVDF membrane surface. In some implementations, gravity filtration may be employed for the filtration of the hybrid solution In gravity filtration, the solution naturally flows through the membrane under its own weight, albeit at a slower rate compared to vacuum filtration.
Once the filtration is done, the liquid phase that passes through the PVDF membrane is collected in a clean container placed under the filtration apparatus. The filtrate may contain dissolved ions, unreacted chemicals, or solvents that were part of the hybrid solution. The solid nanoparticles (the hybrid nanoparticles in this case) remain on the surface of the PVDF membrane. The hybrid nanoparticles particles form a thin layer or cake as the liquid passes through, gradually building up on the PVDF membrane.
After filtration and washing with water and ethanol to remove impurities, the PVDF membrane containing the hybrid nanoparticles as a thin layer is transferred to a suitable drying equipment. In some implementations, vacuum oven is used for drying the hybrid nanoparticles. The vacuum oven is preferred for precise control over temperature and pressure. It allows for gentle drying under reduced pressure to evaporate solvents effectively. In operation, the PVDF membrane with the hybrid nanoparticles is placed inside the vacuum oven. The vacuum is applied to remove air and moisture from the vacuum oven chamber. The temperature is gradually increased to facilitate evaporation of residual water and ethanol The temperature setting depends on the thermal stability of the hybrid nanoparticles. To prevent overheating during the drying process, close monitoring is done to avoid potential agglomeration or decomposition of the hybrid nanoparticles. In another implementation, a desiccator or a rotary evaporator may be used for drying. The drying process is complete when no further weight loss is observed, indicating that all solvents have been removed from the hybrid nanoparticles. Once dried, the PVDF membrane is removed from the drying equipment to prevent contamination.
Advantageously, proper drying prevents agglomeration of the hybrid nanoparticles by removing residual solvents that can act as binding agents. Dry hybrid nanoparticles are more stable and less prone to chemical reactions or degradation during storage or subsequent processing steps. Dried nanoparticles exhibit improved dispersibility and surface area, which are crucial for their effectiveness in various applications, including coatings, composites, and biomedical fields.
FIGs. 4A and 4B are diagrams illustrating scanning electron microscope (SEM) micrographs of the hybrid nanoparticles, in accordance with an embodiment of the present disclosure. Specifically, FIG. 4A is a diagram illustrating a SEM micrograph of the hybrid nanoparticles, in accordance with an embodiment of the present disclosure, and FIG. 4B is another diagram illustrating a magnified SEM micrograph of the hybrid nanoparticles, in accordance with an embodiment of the present disclosure. FIGs. 4A and 4B are described in conjunction with FIGs. 1, 2, and 3. With reference to FIG. 4A, there is shown a diagram illustrating a scanning electron microscope (SEM) micrograph 400A of the hybrid nanoparticles 402 having petal like patterns. With reference to FIG. 4B, there is shown a diagram illustrating a magnified scanning electron microscope (SEM) micrograph 400B of the hybrid nanoparticles 402 having petal like patterns.
A SEM is a technique that uses a focused beam of electrons to scan the surface of a sample and generate high-resolution images. The secondary electrons emitted from the sample are detected, and the resulting signal is used to create a detailed, three-dimensional-like image of surface topography of the sample.
In the illustrated embodiment of FIGs. 4A and 4B, the hybrid nanoparticles 402 includes the copper sulphide and the molybdenum disulphide. The petal like patterns is formed as result of growing the metal sulphide nanoparticles (for example, copper sulphide) on the transition metal dichalcogenide nanoflowers (for example, molybdenum disulphide). The layering or organization creates a hierarchy of structures, from the individual, the porosity and roughness create a large surface area. The petal like patterns trap air pockets, leading to superhydrophobic behaviour, where water droplets bead up and roll off the surface. This is desirable for self-cleaning coatings. The hierarchical structure may influence how light interacts with the material or how electrons flow through it. The SEM micrographs 400A and 400B reveals a highly porous, rough surface consisting of agglomerated nanoparticles or nanostructures with a flower-like or coral-like morphology. The hybrid nanoparticles appear to be composed of smaller nanoscale building blocks that have assembled into these intricate, hierarchical structures.
FIG. 5 is a graphical representation illustrating an energy dispersive spectroscopy (EDS) analysis of the hybrid nanoparticles, in accordance with an embodiment of present disclosure. FIG. 5 is described in conjunction with FIGs. 1, 2, 3, and 4A and 4B. With reference to FIG. 5, there is shown a graphical representation 500 depicting an energy dispersive spectroscopy (EDS) analysis of hybrid particles (for example, the hybrid nanoparticles 402). Specifically, the graphical representation 500 depicts the absorption of high energy electron beam by the hybrid nanoparticles 402 and the intensity (also called x-ray counts) corresponding to an element present in the hybrid nanoparticles 402. The high energy electron beam is measured in kilo electron volt (keV) in an abscissa axis (X-axis). The intensity is expressed in arbitrary units in an ordinate axis (Y-axis).
The graphical representation 500 includes a first peak 502, a second peak 504, a third peak 506, a fourth peak 508, and a fifth peak 510. Each peak corresponds to the characteristic X-ray energy emitted by a particular element present in the hybrid nanoparticles 402, and the height of each peak reflects the relative abundance of that element in the hybrid nanoparticles 402. For example, the first peak 502 depicts the presence of copper (Cu) element in the hybrid nanoparticles 402, and the height of the first peak 502 reflects the high abundance of the copper in the hybrid nanoparticles 402. Similarly, the second peak 504 indicates the presence of both molybdenum (Mo) and sulphur (S). The third peak 506 indicates the presence of only molybdenum (Mo). The fourth peak 508 and the fifth peak 510 depict a presence of copper (Cu). The presence and relative intensities of the S, Cu, and Mo peaks confirm the successful synthesis of the hybrid nanoparticles 402, where for example, copper sulphide have been grown on the surface of transition metal molybdenum disulphide nanoflowers.
FIG. 6 is a diagram illustrating X ray diffraction (XRD) analysis of the hybrid nanoparticles and its constituents, in accordance with an embodiment of present disclosure. FIG. 6 is described in conjunction with FIGs. 1 to 5. With reference to FIG. 6, there is shown a XRD analysis diagram 600 of the hybrid nanoparticles. The XRD analysis diagram 600 includes a first XRD pattern 602 of the metal sulphide nanoparticles (for example, copper sulphide), a second XRD pattern 604 of the transition metal dichalcogenide nanoflowers (for example, molybdenum disulphide) and a third XRD pattern 606 of the hybrid nanoparticles 402. The XRD analysis diagram 600 further includes specific a first dotted box 608 which corresponds to crystallographic plane “(002)”, a second dotted box 610 which corresponds to crystallographic planes “(100)” and “(101)”, a third dotted box 612 which corresponds to crystallographic plane “(102)”, a fourth dotted box 614 which corresponds to crystallographic plane “(110)”, a fifth dotted box 616 which corresponds to crystallographic plane “(114)” and a sixth dotted box 618 which corresponds to crystallographic plane “(203)”.
XRD is used to identify the crystallographic structure, composition, and physical properties of materials. Peaks in the XRD pattern correspond to atomic planes in a crystal lattice and their intensities relate to the number of such atomic planes and the orientation of the crystals. The diffraction angle denoted by 2? is measured in degrees in an abscissa axis (X-axis). The intensity is expressed in arbitrary units in an ordinate axis (Y-axis). Peaks at specific 2? degrees values indicate the presence of specific crystallographic planes. Higher peaks indicate more atoms arranged in the corresponding crystal plane. The first XRD pattern 602 of the metal sulphide nanoparticles (for example, copper sulphide) includes peaks at 2? values corresponding to specific crystallographic planes of the metal sulphide nanoparticles (e.g., “(100)”, “(101)”, “(102)”, “(110)”, “(114)”, and “(203)”). These peaks confirm the crystalline structure of the metal sulphide nanoparticles. The prominent peaks around 30-50 degrees indicate the presence of specific the metal sulphide nanoparticles crystallographic planes.
The second XRD pattern 604 of the transition metal dichalcogenide nanoflowers includes peak at crystallographic plane “(002)”. The characteristic peak for the transition metal dichalcogenide nanoflowers indicating its layered structure. The transition metal dichalcogenide nanoflowers has fewer and less intense peaks compared to the metal sulphide nanoparticles, which is typical for layered materials like transition metal dichalcogenide nanoflowers.
The third XRD pattern 606 pattern of the hybrid nanoparticles shows peaks from both the metal sulphide nanoparticles and the transition metal dichalcogenide nanoflowers. The presence of peaks from both the metal sulphide nanoparticles and the transition metal dichalcogenide nanoflowers indicates successful deposition of the metal sulphide nanoparticles on the transition metal dichalcogenide nanoflowers. The third XRD pattern 606 confirms formation of the hybrid nanoparticles. Peaks at 2? values corresponding to the crystallographic planes (e.g., “(100)”, “(101)”, “(102)”, “(110)”, “(114)”, and “(203)”) are seen for the metal sulphide nanoparticles.
Example 1
An example illustrating the synthesis of the fluorine-free superhydrophobic and icephobic coating through a series of steps:
Step 1: Synthesis of molybdenum sulphide (MoS2): Stoichiometric (1:1 molar ratio) amounts of sodium molybdate dihydrate and thiourea were added to an equal mixture of deionized water and ethanol, and sonication was carried out for 30 min. The solution was then transferred to a Teflon-lined autoclave and heated to 200 °C for 24 h. The obtained mixture was centrifuged, washed with water and ethanol, dried, and powdered to obtain MoS2 particles.
Step 2: Preparation of the hybrid nanoparticles consisting of MoS2 and copper sulphide: A 7.5 g/L dispersion of MoS2 particles in isopropyl alcohol (IPA) was prepared, and probe sonication was done for 15 minutes. A 25% solution of ammonia was added dropwise to the dispersion of MoS2 particles and the IPA under magnetic stirring until the pH reached ten. As a result, alkalized nanoflower solution is obtained A 1.25 M aqueous sodium sulphide (Na2S) solution was added dropwise to the alkalized nanoflower solution under magnetic stirring over a period of 10 min to obtain pre hybrid solution. After 2 h of magnetic stirring, a 2.5 M aqueous copper chloride (CuCl2) solution was added dropwise to the pre hybrid solution under stirring over a period of 10 min. As a result, hybrid solution is obtained. After 1 h of magnetic stirring, the hybrid solution was filtered using a PVDF membrane, washed with water and ethanol, dried, and powdered to obtain the hybrid nanoparticles consisting of MoS2 and copper sulphide.
Step 3: Fabrication of the fluorine-free superhydrophobic and icephobic coating: Glass slides were used as the substrates for the coatings. DGEBA epoxy resin and an amine-based hardener were mixed thoroughly in a 100:24 weight ratio and then dropped and spread on the glass slides. The coated glass slides were left at room temperature for 15 mins to achieve a gel-like semi-cured state of epoxy. Following this, the particles were taken in varying weight ratios of 1:1 against the epoxy present on the slides and dispersed in acetone via probe sonication for 30 seconds. The dispersion was poured into a spray gun and sprayed onto the epoxy-covered glass slide at low pressure (approximately 2 bar) such that all the particles were used in the coating. Finally, the coated glass slides were fully cured overnight at 80 degrees Celsius.
By following these steps, the fluorine-free superhydrophobic and icephobic coating was synthesized.
Modifications to embodiments of the present disclosure described in the foregoing are possible without departing from the scope of the present disclosure as defined by the accompanying claims. Expressions such as "including", "comprising", "incorporating", "have", "is" used to describe and claim the present disclosure are intended to be construed in a non-exclusive manner, namely allowing for items, components or elements not explicitly described also to be present. Reference to the singular is also to be construed to relate to the plural. The word "exemplary" is used herein to mean "serving as an example, instance or illustration". Any embodiment described as “exemplary” is not necessarily to be construed as preferred or advantageous over other embodiments and/or to exclude the incorporation of features from other embodiments. The word "optionally" is used herein to mean "is provided in some embodiments and not provided in other embodiments". It is appreciated that certain features of the present disclosure, which are, for clarity, described in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features of the present disclosure, which are, for brevity, described in the context of a single embodiment, may also be provided separately or in any suitable combination or as suitable in any other described embodiment of the disclosure.

, Claims:CLAIMS
We claim:
1. A method (100) for synthesizing a fluorine-free superhydrophobic and icephobic coating, the method comprising:
reacting a transition metal salt and an organic sulphur reagent to form transition metal dichalcogenide nanoflowers;
treating the transition metal dichalcogenide nanoflowers with ammonia to obtain an alkalized nanoflower solution;
reacting a metallic sulphide salt and a metallic chloride salt to produce metal sulphide nanoparticles;
combining the alkalized nanoflower solution and the metal sulphide nanoparticles to obtain hybrid nanoparticles (402);
applying a polymeric resin coating on a substrate and partially curing the polymeric resin coating;
dispersing the hybrid nanoparticles (402) in a solvent and applying the dispersed hybrid nanoparticles onto the partially cured polymeric resin coating; and
fully curing the polymeric resin coating having the hybrid nanoparticles (402) dispersed therein to obtain the fluorine-free superhydrophobic and icephobic coating, wherein the dispersed hybrid nanoparticles have a micro-nano rough surface on the fluorine-free superhydrophobic and icephobic coating having a water contact angle greater than 150 degrees and a water sliding angle less than 10 degrees.
2. The method (100) as claimed in claim 1, wherein the reaction of the transition metal salt and the organic sulphur reagent to form the transition metal dichalcogenide nanoflowers comprises:
mixing the transition metal salt and the organic sulphur reagent in a ratio of unity to obtain a first mixture;
adding the first mixture to a solution of deionised water and ethanol to obtain a first solution and performing sonication on the first solution to obtain a second solution;
placing the second solution in a Teflon lined autoclave and heating the second solution for 22 to 26 hours at a temperature ranging from 180 to 220 degrees Celsius to obtain a heated solution; and
centrifuging, washing and drying the heated solution to obtain the transition metal dichalcogenide nanoflowers.
3. The method (100) as claimed in claim 2, wherein the sonication on the first solution is performed for 28 min to 32 minutes.
4. The method (100) as claimed in claim 1, wherein the transition metal salt is sodium molybdate dihydrate and the organic sulphur reagent is thiourea.
5. The method (100) as claimed in claim 1, wherein the metal sulphide nanoparticles comprise at least one of: copper suphide (CuS), tungsten disulfide (WS2), iron sulfide (FeS), nickel sulfide (NiS), and silver sulfide (Ag2S).
6. The method (100) as claimed in claim 1, wherein the combining of the alkalized nanoflower solution and the metal sulphide nanoparticles to obtain the hybrid nanoparticles (402) comprises:
mixing and heating the alkalized nanoflower solution and the metal sulphide nanoparticles for 56 to 64 minutes to obtain a synthesis solution;
filtering the synthesis solution using a high-density polymer membrane and washing the filtrate with water and ethanol; and
drying and powdering the washed filtrate to obtain the hybrid nanoparticles (402).
7. The method (100) as claimed in claim 1, wherein the combining of the alkalized nanoflower solution and the metal sulphide nanoparticles to obtain the hybrid nanoparticles (402) is carried out via a sol-gel method.
8. The method (100) as claimed in claim 1, further comprising selecting a ratio by weight of the hybrid nanoparticles (402) to the polymeric resin coating to control the amount of hybrid nanoparticles on the surface the fluorine-free superhydrophobic and icephobic coating.
9. The method (100) as claimed in claim 8, wherein the fluorine-free superhydrophobic and icephobic coating comprises the hybrid nanoparticles (402) and the polymeric resin coating applied on the substrate in the ratio by weight of 1:1.
10. The method (100) as claimed in claim 9, wherein when the ratio by weight of the hybrid nanoparticles (402) to the polymeric coating applied on the substrate is 1:1, the fluorine-free superhydrophobic and icephobic coating has the water contact angle of 156.68 degrees.
11. A fluorine-free superhydrophobic and icephobic coating comprising:
one part by weight of a polymeric resin coating applied on a substrate; and
one part by weight of hybrid nanoparticles (402) applied on the polymeric resin coating after partial curing, wherein the hybrid nanoparticles (402) comprise metal sulphide nanoparticles deposited on transition metal dichalcogenide nanoflowers, wherein the polymeric resin coating with the hybrid nanoparticles (402) is fully cured to obtain the fluorine-free superhydrophobic and icephobic coating, and wherein the fluorine-free superhydrophobic and icephobic coating has a water contact angle greater than 150 degrees and a sliding angle less than 10 degrees.