Description:FIELD OF THE INVENTION:
The invention generally relates to the field of air cooling, and more particularly it relates to a nanofluid-polymer coating for quick thermal dissipation in electronic devices.

BACKGROUND OF THE INVENTION:
The following background information may present examples of specific aspects of the prior art (e.g., without limitation, approaches, facts, or common wisdom) that, while expected to be helpful to provide additional aspects of the prior art, is not to be construed as limiting the present invention, or any embodiments thereof, to anything stated or implied therein or inferred thereupon.
Global climate change poses the greatest challenge to human civilization in the twenty-first century. One example of abnormal energy consumption that needs to be curbed is high efficiency energy use, which must be minimized to reduce carbon emissions in essential businesses. It is consequently necessary to incorporate effective thermal management technologies into the processes for creating new goods, machinery, and industrial processes.
For every 100 square feet, one ton of air conditioning is needed; however, for data centers, this requirement is increased to five tons per unit of space. This excessive demand for air conditioning utilizes more electricity than necessary, and this should be reduced. Thus, by using this technology, the amount of extra electricity used for air conditioning systems can be decreased which ultimately shall reduce the consumption of electricity. We may also use the cooling mechanism in the room as an example. It should take less time and use less energy to bring the hotter area down to room temperature or ambient temperature.
Technological developments in electronics industries coupled with consumer aspirations for more energy-efficient products have led to the creation of electronic gadgets that are small in size, perform better, process information faster, and yet consume large amounts of power. The thermal management of these electronic devices is important since excessive heat can damage the devices' lifespan, performance, and dependability in addition to causing abrupt thermal failure and runaway. Despite the significant advancements in the previous ten years in cooling technologies, including heat exchangers, heat pipe, heat pump, micro channel, thermoelectric, PCM, and thermoelectric cooling, immersion cooling; there are still certain difficulties in controlling the thermal expansion of electronic equipment. Since electronic components are getting smaller and electronic chips are getting more powerful every day, efficient heat dissipation by a thermal interface material (TIM) is essential for the safe and dependable operation of the majority of electronic systems. To dissipate heat to a heat sink as efficiently as possible, a range of TIMs that are suitably adjustable for different kinds of heat sources are available. However, substrates and materials with good electrical insulation and thermal conductivity are needed for the electronic portions of today's designs.
Numerous attempts have been made and several prior art material and methods are known for heat dissipation coatings. Even though these innovations may be suitable for the specific purposes to which they address, however, they would not be as suitable for the purposes of the present invention.
For example, Chinese Patent application CN105645899A to Wang Qiuqin discloses a Graphene oxide silicon based far infrared heating coating and preparation method thereof.
For example, Chinese Patent application CN106747529A to Zhao Yongwu et al. discloses Graphene reinforced abrasion-resistant easy-to-solidify aluminum oxide ceramic coating and preparation method thereof.
It is apparent now that numerous innovations that are adapted to a variety of materials, devices and methods related to heat dissipation coatings and materials, which have been previously developed in the prior art that are adequate for various purposes. Furthermore, even though these innovations may be suitable for the specific purposes to which they address, accordingly, they would not be suitable for the purposes of the present invention. Thus, the present invention is needed to overcome the drawbacks of the present prior arts.

SUMMARY OF THE INVENTION:
The purpose of the present invention is to provide a nanofluid-polymer matrix and a dispersed filler with a high heat conductivity and diffusability by molecularly combining graphene oxides (GO) and aluminum (Al) composite powders to provide a solution that acts as a heat-dissipation materials in various industrial fields. However, for combining electrical insulation and higher thermal conductive application, the combination of GO and Al is modified in the desired ratio and in a desired process to overcome the deficiencies in the prior arts.
The composite matrix formed by the method of the present invention allows existing oxygen atoms due to reduction reaction at graphene oxide/alumina interfaces to get uniformly distributed and formed a strong interaction with the alumina matrix. In addition, the reduction of graphene oxide improved the composites' toughness and hardness at the same time it acts as a bridge to stop cracks in the alumina matrix. It is made clear that when the molecular-level mixing procedure is used, graphene can be used as potential reinforcements to improve the mechanical properties of coating materials. Hence, the graphene oxide in aluminum substance is added in one of the range of 1 to 10 % weight, wherein the DSC and thermal conductivity tests are conducted for ensuring specific heat and thermal diffusivity of the GO/Al samples.
According to an aspect of the present invention, the presence of Alumina in the matrix provides excellent thermal conductivity with improved thermal transfer characteristics are produced, enabling effective heat dissipation while Alumina in the composite improves stability and longevity of the matrix.
According to another aspect of the present invention, the lightweight nature of graphene makes it a useful ingredient in the matrix for coatings based on alumina, which can assist lower the overall weight of the coating. This benefit is especially helpful in aircraft and automotive applications where low weight is crucial to overall performance and fuel efficiency.
According to another aspect of the present invention, the material Graphene when combined with Alumina, it improves the mechanical strength and hardness of the matrix, thereby enhancing resistance to wear, abrasion, and mechanical stress to improve durability of the composite coating.
According to another aspect of the present invention, the ability of alumina to resist corrosion is essential for applications of the composite matrix as a coating material in the corrosive or harsh environments.
According to another aspect of the present invention, the composite matrix material is applicable in several industries without limitation in Automotive industry, Electronics cooling, Data centers, Aerospace and aviation, Energy storage and conversion, Power generation, Building materials, medical devices or the like.
According to another aspect of the present invention, the composite matrix material is primarily used as heat dissipation coatings by without limitation in HVAC and refrigerant manufacturers, Heat Exchangers, Energy storage and battery manufacturers, Electronics and semiconductor industries, automotive industries, Construction and Building Materials or the like.
The present invention allows to overcome the above-mentioned conventional problems of the prior arts; therefore, it is an object of the present invention is to prepare nanofluid-polymer matrix that acts as a heat dissipating coating material that facilitate in improved heat dissipation in X-Y-Z direction.
Another objective of the present invention is to provide a nanofluid-polymer matrix coating material that uses functionalized graphene with alumina (Al2O3) to assist in quick heat dissipation in Z direction.
These and other objectives, advantages and aspects of the invention will become apparent from the following detailed description, taken in conjunction with the accompanying drawings, which illustrate, by way of example, the features in accordance with embodiments of the invention. The summary is not intended to limit the scope of the invention, which is defined solely by the claims attached hereto.

BRIEF DESCRIPTION OF THE DRAWINGS:
The invention will now be described, by way of example, with reference to the accompanying drawings, in which:
FIG. 1 illustrates the functionalized graphene with alumina in the composite matrix coating of the present invention on the aluminum alloy sheet showing mechanism of heat transfer in X-Y-Z direction, in accordance with an embodiment of the present invention.
Like reference numerals refer to like parts throughout the various views of the drawings.

DETAILED DESCRIPTION OF THE INVENTION:
The following detailed description is merely exemplary in nature and is not intended to limit the described embodiments or the application and uses of the described embodiments. All of the implementations described below are exemplary implementations provided to enable persons skilled in the art to make or use the embodiments of the disclosure and are not intended to limit the scope of the disclosure, which is defined by the claims. Furthermore, there is no intention to be bound by any expressed or implied theory presented in the preceding technical field, background, brief summary or the following detailed description. It is also to be understood that the specific system and processes described in the following specification, are simply exemplary embodiments of the inventive concepts defined in the appended claims. Throughout this specification the word “comprise” or variations such as “comprises or comprising”, will be understood to imply the inclusions of a stated element, integer or step, or group of elements, integers or steps, but not the exclusions of any other element, integer or step or group of elements, integers or steps. Specific dimensions and other physical characteristics relating to the embodiments disclosed herein are therefore not to be considered as limiting, unless the claims expressly state otherwise.
According to several embodiment of the present invention, a method of preparation of a hybrid graphene-alumina nanofluid-polymer matrix for quick thermal dissipation when applied as a coating material to accelerate the cooling process by moving heated electrons outward and cools the space more quickly in comparison to the existing heat dissipation coating materials. The graphene-alumina nanocomposites of the present invention allow significantly enhanced thermal management capabilities through phonon-mediated conduction in graphene sheets and electron transport in the alumina matrix, while interfacial thermal transport plays a crucial role at material boundaries, thereby the present invention allows in increasing the heat transmission capacity from two to five times in this direction to save time and energy while also enabling faster cooling. Graphene creates thermal networks within the alumina matrix, effectively bridging alumina grains and reducing thermal boundary resistance. This improvement manifests in better temperature distribution, reduced thermal resistance, and enhanced cooling capacity, making the coating material ideal for applications in compact heat exchangers, electronic cooling systems, and automotive radiators. The overall heat exchange effectiveness typically exceeds 85%, with thermal efficiency above 90% is achieved, while providing energy savings of 20-40% in practical applications. However, optimal performance requires careful consideration of factors such as graphene content, interface engineering, flow dynamics, and operational parameters to maintain long-term reliability. The present invention effectively utilizes graphene's exceptional thermal conductivity to create efficient heat dissipation systems for electronics equipments that can reduce cooling energy use by up to thirty percent when compared to traditional methods.
According to an aspect of the present invention, a method of preparation of nanofluid-polymer matrix coating material, wherein the method comprises a first part for preparation of the graphene-alumina powder and a second part of the method for preparation of the nanofluid-polymer matrix that acts as a heat dissipating coating material characterized in that the first part of the method comprises, mixing aluminum nitrate or aluminum isopropoxide in amounts ranging from 2 to 8 parts (w/w) and dissolving it in 200–600 parts (v/v) of an organic solvent, then, stirring the resulting mixture for 30–120 minutes to form a first solution, parallelly preparing a second solution using graphene oxide in concentration in 0.05 to 0.5 parts (w/w) with 100-1000 parts (v/v) of deionized (DI) water, thereafter, sonicating the second solution for 60–180 minutes to achieve uniform dispersion, then, mixing the second solution with the first solution under continuous stirring using the hydrothermal method at 100–300°C for 1–12 hours to obtain a precipitate, then the precipitate is washed with organic solvents and DI water to remove impurities, and then, it is dried at 50–150°C for 12–24 hours to obtain the graphene-alumina nano-composite powder; and the second part of the method comprises, mixing N-methyl pyrrolidone (NMP) or dimethyl esters or triethyl phosphate (TEP) or any combination thereof in amounts ranging from 500 to 1500 parts (v/v) with the graphene-alumina nano-composite powder, in concentrations between 0.05 and 0.5 parts (w/w), and sonicated for 15–25 minutes to achieve homogenous third solution, then, binding materials are mixed in amounts ranging from 1 to 10 parts (w/w) with the third solution to get dissolved completely while stirring the mixture continuously for 12–24 hours to result into the nanofluid-polymer matrix coating material having functionalized graphene with alumina (Al2O3) for improved heat dissipation in X-Y-Z direction.
According to another aspect of the present invention, the organic solvent is selected from a group consisting of ethanol, isopropyl alcohol, ketone.
According to another aspect of the present invention, the method uses a magnetic stirrer.
According to another aspect of the present invention, the binding materials is selected from a group consisting of polycarbonate (PC), Polytetrafluoroethylene (PTFE), Nylon, Regenerated Cellulose (RC), Mixed Cellulose Ester, or a combination thereof.
According to another aspect of the present invention, the functionalizing graphene with alumina (Al2O3) introduces structural defects and interfaces that increases phonon scattering, which impede the z-direction phonon transport for improved heat dissipation in X-Y-Z direction.
According to another aspect of the present invention, the thermal conductivity of the nanofluid-polymer matrix coating material over aluminum substrate of thickness 0.25mm is at least 157.86 W/m-K in the Z-direction.
According to an embodiment of the present invention, the presence of graphene in the nanofluid-polymer composite matrix (100) allows the surface of the substrate to significantly improve heat transfer due to its high thermal conductivity (3000 W/mk).
In addition to having greater mechanical strength. The greater pumping power of hot electrons (110) from the surface of the GO/Al hybrid nanofluid coating is apparent by its heat dissipation property as a result, the hybrid nanofluid coating's heat conductivity improves after the aluminum alloy surface is coated by the GO/Al hybrid nanofluid coating as shown in Fig:1. The material's ability to absorb heat improves with thermal conductivity, thereby contributes towards lower electricity costs and better efficiency of the device.
Chemical bonds between Al ions from aluminum substance and the hydroxyl radical functional groups like -COOH and -OH found on the graphene oxide surface form a chemical bond with the Al ion. Prior to the bonded Al-OH on the carbon atom of GO being converted into the Al2O3 phase by heating, the hydroxyl group (OH) bonded with the carbon atom of GO is first reacted with Al ions. This produces the reduction of H2O and Al-O-C bonds that are newly created and present in modest amounts at the reduced GO/alumina interface. These interactions assist in creating an electron (110) flow path that allows heat to be dissipated throughout the material.
According to an exemplary embodiment of the present invention, it solves the problems of the prior arts for not able to properly dissipate heat even the existing material use graphene, as in graphene, which is a single layer of carbon atoms arranged in a hexagonal lattice, the dominant mechanism for thermal conduction is through phonons - quantized vibrations of the crystal lattice. Unlike in 3D materials where phonons can propagate in all three spatial dimensions, the 2D nature of graphene results in some unique behavior when it comes to phonon transport. The z-direction refers to the axis perpendicular to the graphene plane. In this direction, graphene has very weak van-der-Waals interactions between the individual layers. This leads to a high thermal resistance to heat flow across the z-axis, as phonons have difficulty propagating perpendicularly through the layers. Conversely, within the x-y plane of the graphene sheet, the strong covalent bonds between the carbon atoms allow phonons to travel very efficiently, resulting in exceptionally high in-plane thermal conductivity. This anisotropy, with much higher thermal conduction parallel to the graphene plane compared to the perpendicular direction, is a defining characteristic of heat transfer in this 2D configuration of the existing materials. In contrast to it, the composite matrix of the present invention uses concept of z-direction phonon coupling and transport when using graphene in applications that require efficient heat dissipation, as the weak interlayer interactions can impede vertical heat flow. To enhance the z-direction phonon transfer, various methods such as introducing structural defects or functionalizing the graphene surface is used, thereby the functionalizing graphene with alumina (Al2O3) has a significant impact on the z-direction heat transfer in this composite material of the present invention. The addition of the alumina layer (106) can create stronger bonding and interactions between the graphene layers (108), improving the interlayer phonon coupling and allowing heat (104) to more efficiently transfer in the z-direction, perpendicular to the graphene plane. Further, the alumina functionalization also introduces structural defects and interfaces that can increase phonon scattering, which could impede the z-direction phonon transport to some degree to balance between the enhanced phonon coupling and the increased scattering for better heat dissipation in comparison to the existing arts. The improved coupling dominates, the z-direction thermal conductivity could increase, potentially reducing the stark anisotropy in thermal properties between the in-plane and out-of-plane directions, making the material's thermal behavior more isotropic. This is significant because improving the z-direction heat transport in the graphene-alumina composite. The composite matrix (100) of the present invention is much efficient than bare aluminum as bare aluminum (102) typically has poor thermal conductivity in the thickness (z) direction due to its isotropic 3D structure. By engineering the graphene-alumina interface to enhance z-direction heat flow, this composite material of the present invention outperforms aluminum in applications that require efficient thermal transport perpendicular to the plane, such as heat sinks or thermal interface materials or heat exchangers. Thus, functionalizing graphene with alumina (Al2O3) of the present composite matrix plays a significant impact on the z-direction controlling the directional dependence of phonon transport is the key aspect of leveraging graphene's remarkable thermal properties for practical applications. Fig. 1 suggests the mechanism of heat transfer via the composite matrix coating of the present invention on the aluminum alloy sheet (hot electrons (110) travel from hot region to cold region in closer visualization).
According to an exemplary embodiment of the present invention, the method of preparing the graphene-alumina (Al2O3) nanofluid-polymer composite matrix coatings (100) in two parts, the first part results into preparation of the graphene-alumina powder and then the second part of the method is preparation of the nanofluid-polymer matrix that acts as a heat dissipating coating material. The first part of the method of preparation begins by mixing aluminum nitrate or aluminum isopropoxide in amounts ranging from 2 to 8 parts (w/w) and dissolving it in 200–600 parts (v/v) of an organic solvent, such as ethanol, isopropyl alcohol, or ketone. Then stirring the resulting mixture for 30–120 minutes to ensure proper dissolution using without limitation a magnetic stirrer. In parallel, graphene oxide solution is prepared by dispersing graphene oxide in deionized (DI) water, with concentrations ranging from 0.05 to 0.5 parts (w/w). Thereafter, sonicating the graphene oxide solution for 60–180 minutes to achieve uniform dispersion. Then mixing the sonicated graphene oxide solution with the dissolved aluminum compound under continuous stirring. After thorough mixing, the mixture is processed using the hydrothermal method at 100–300°C for 1–12 hours. Following this, the sample is washed with organic solvents and DI water to remove impurities. Finally, the sample is dried at 50–150°C for 12–24 hours to obtain the graphene-alumina nano-composite powder. According to another exemplary embodiment of the present invention the second part of the method of preparation begins by mixing N-methyl pyrrolidone (NMP), dimethyl esters, and triethyl phosphate (TEP) in amounts ranging from 500 to 1500 parts (v/v). Then, adding the graphene-alumina nano-composite powder, in concentrations between 0.05 and 0.5 parts (w/w), to this solution and sonicate it for 15–25 minutes to achieve homogeneity. Then using binding materials, such as polycarbonate (PC), polytetrafluoroethylene (PTFE), nylon, regenerated cellulose (RC), or mixed cellulose ester, in amounts ranging from 1 to 10 parts (w/w). Thereafter, allowing the binding materials to get dissolved completely while stirring the mixture continuously for 12–24 hours. The prepared solution is the nanofluid-polymer matrix coating material that is ready for coating onto an aluminum sheet for efficient heat dissipation.
According to best mode of the present invention the method of preparation of the nanofluid-polymer matrix coating material (100) is processed using the steps of adding Aluminum nitrate or Aluminum isopropoxide in one of the amounts of 4 parts (w/w) in a 300 parts (v/v) organic samples like ethanol, isopropyl alcohol, ketone, or the like, then mixing the mixture using a magnetic stirrer for 90 minutes to form a first solution. Thereafter, the precipitate is washed Graphene Oxide of the amount of 0.2 parts (w/w) in 500 parts (v/v) of DI water and sonicate it for 120 minutes to form a second solution. Then the first solution and the second solution is mixed using a magnetic stirrer. following hydrothermal method for 6 hours at 200?C, thereafter the precipitate produced is washed with organic solvents and DI water and is allowed to get dried for 18 hours at 100?C to form graphene-alumina nano-composite powder. Thereafter, N-methyl pyrrolidone (NMP), Dimethyl esters, and Triethyl phosphate (TEP) in the amount of 1000 parts (v/v) is mixed with the prepared graphene-alumina nano-composite powder in the range of 0.2 parts (w/w), and sonicated for 20 mins to form a third solution. Thereafter, binding materials selected from a group consisting of polycarbonate (PC), Polytetrafluoroethylene (PTFE), Nylon, Regenerated Cellulose (RC), Mixed Cellulose Ester, or any combination thereof or the like in the range of 5 parts (w/w) is mixed with the third solution with constant stirring for 18 hours till complete dissolution to form the nanofluid-polymer matrix coating material that is ready to coat on an aluminum sheet/substrate.

TEST METHODS
According to another exemplary embodiment of the present invention, the nanofluid-polymer matrix coating material is tested in CMC laboratory, USA and the testing reports cover detailed materials characterization testing performed by CMC Laboratories on an aluminum sheet material coated with the Alumina Graphene composite. The primary focus was on measuring the thermal conductivity of this aluminum coated sheet using the Laser Flash Analysis (LFA) technique. LFA is a well-established method for determining the thermal transport properties of solid materials. It involves rapidly heating one side of a thin sample with a laser pulse and then measuring the resulting temperature rise on the opposite side using an infrared detector. By analyzing this temperature response curve, the thermal diffusivity of the material can be calculated.
To supplement the LFA testing, we have also conducted Differential Scanning Calorimetry (DSC) analysis to directly measure the heat capacity (Cp) of the coated aluminum. However, we have also measured the specific heat from K. R. Mangalam University located in New Delhi , India, and observed the approximated values as CMC laboratories have calculated. Knowing the heat capacity, along with the measured thermal diffusivity and the material density, allows the overall thermal conductivity to be computed. The DSC testing followed a standard temperature program, using a nitrogen atmosphere and an aluminum sample pan. The resulting heat capacity data was then used as an input for the LFA thermal conductivity calculations. For the LFA measurements, the researchers adhered to the ASTM E1461 standard test method. This involves carefully controlling parameters like the laser pulse duration, sample thickness, and temperature rise on the back surface. The data was then fit to a one-dimensional heat flow model to extract the thermal diffusivity value.
As shown in Figure 1, the thermal conductivity of the present nanofluid-polymer matrix coating material (100) over aluminum substrate (102) is shown, where the coating (100) of the present invention allows quick heat dissipation in the Z-direction in addition to the X-Y direction. According to an exemplary embodiment, the nanofluid-polymer matrix coating material (100) of the present invention is applied over aluminum substrate (102) of thickness 0.25mm that is tested for thermal conductivity in Z-direction at CMC Lab, USA using Laser Flash Analysis (LFA), wherein it is found that the thermal conductivity is 157.86 W/m-K in the Z-direction, which is far beyond the thermal conductivity of aluminum substrate (thermal conductivity of 0.97 W/m-K for 3mm RS Pro Bare Aluminium Sheet). This high thermal conductivity value of the coating material of the present invention is makes it suitable for applications requiring excellent thermal transport properties. The close agreement between the measured and expected values for the reference material builds confidence in the reliability of the coated aluminum results. In comparison with other composites like Panasonic Graphite TIM compressible type material featuring anisotropic thermal conductivity in-plane (X-Y direction) conductivity of 200 to 400 W/m·K and through-thickness (Z direction) conductivity of 13 W/m·K, when compressed at 600 kPa. However, the coating material of the present invention is showing much more thermal conductivity in the Z direction indicating its vast application in the industry for efficient and quick heat dissipation.
Overall, this comprehensive materials characterization provides valuable data on the thermal performance of the coated aluminum sheet. The combination of DSC and LFA testing generates a thorough understanding of the material's thermal properties, which could inform its selection and use in thermally-critical applications.
Because many modifications, variations, and changes in detail can be made to the described preferred embodiments of the invention, it is intended that all matters in the foregoing description and shown in the accompanying drawings be interpreted as illustrative and not in a limiting sense. Thus, the scope of the invention should be determined by the appended claims and their legal equivalence.
, Claims:We Claim:
1. A method of preparation of nanofluid-polymer matrix coating material (100), wherein the method comprises a first part for preparation of the graphene-alumina powder and a second part of the method for preparation of the nanofluid-polymer matrix that acts as a heat dissipating coating material characterized in that:
a) the first part of the method comprises, mixing aluminum nitrate or aluminum isopropoxide in amounts ranging from 2 to 8 parts (w/w) and dissolving it in 200–600 parts (v/v) of an organic solvent then, stirring the resulting mixture for 30–120 minutes to form a first solution, parallelly preparing a second solution using graphene oxide in concentration in 0.05 to 0.5 parts (w/w) with 100-1000 parts (v/v)of deionized (DI) water, thereafter, sonicating the second solution for 60–180 minutes to achieve uniform dispersion, then, mixing the second solution with the first solution under continuous stirring using the hydrothermal method at 100–300°C for 1–12 hours to obtain a precipitate, then the precipitate is washed with organic solvents and DI water to remove impurities and then, it is dried at 50–150°C for 12–24 hours to obtain the graphene-alumina nano-composite powder; and
b) the second part of the method comprises, mixing N-methyl pyrrolidone (NMP) or dimethyl esters or triethyl phosphate (TEP) or any combination thereof in amounts ranging from 500 to 1500 parts (v/v) with the graphene-alumina nano-composite powder, in concentrations between 0.05 and 0.5 parts (w/w), and sonicated for 15–25 minutes to achieve homogenous third solution, then, binding materials are mixed in amounts ranging from 1 to 10 parts (w/w) with the third solution to get dissolved completely while stirring the mixture continuously for 12–24 hours to result into the nanofluid-polymer matrix coating material having functionalized graphene with alumina (Al2O3) for improved heat dissipation in X-Y-Z direction.
2. The method as claimed in claim 1, wherein the organic solvent is selected from a group consisting of ethanol, isopropyl alcohol, ketone.
3. The method as claimed in claim 1, wherein the method uses a magnetic stirrer.
4. The method as claimed in claim 1, wherein the binding materials is selected from a group consisting of polycarbonate (PC), Polytetrafluoroethylene (PTFE), Nylon, Regenerated Cellulose (RC), Mixed Cellulose Ester, or a combination thereof.
5. The method as claimed in claim 1, wherein the functionalizing graphene with alumina (Al2O3) introduces structural defects and interfaces that increases phonon scattering, which impede the z-direction phonon transport for improved heat dissipation in X-Y-Z direction.
6. The method as claimed in claim 1, wherein the thermal conductivity of the nanofluid-polymer matrix coating material over aluminum substrate of thickness 0.25mm is at least 157.86 W/m-K in the Z-direction.