Description:FIELD OF INVENTION
[0001] The present invention relates to the field of fiber spinning technologies, and more particularly to systems and methods for fabricating nanofiber-coated polymer composite yarns. Specifically, the invention pertains to a wet-electrospinning technique that integrates wet spinning and electrospinning processes in a single apparatus, wherein the coating of nanofibers over the core fiber is facilitated at the liquid surface to produce composite yarns with enhanced interfacial interaction.

BACKGROUND
[0002] The technique of wet spinning has been established and utilized for several decades for the production of micro-scale fibers in various industrial applications. In contrast, electrospinning is a relatively recent and versatile fabrication technique that can produce nanofibers with diameters in the nanometer range. Nanofibers produced by electrospinning exhibit exceptionally high surface area-to-volume ratios, rendering them suitable for a wide array of applications, including filtration, biomedical scaffolds, sensors, and smart textiles.
[0003] Conventional electrospinning processes predominantly yield nonwoven nanofibrous mats or membranes. Although these mats can be subsequently processed and converted into yarns, their inherently poor mechanical strength and limited structural integrity restrict their direct applicability in load-bearing or flexible textile-based applications. Consequently, there exists a need to develop improved methods for fabricating nanofiber-coated composite yarns or composite structures with enhanced mechanical robustness and versatility, suitable for diverse end-use applications.
[0004] A combination of the two spinning technologies, wet and electrospinning (WeTro), can result in high-strength, high surface area yarns, wherein the wet-spun fiber is continuously coated with electrospun fibers to develop a nanofiber-coated composite yarn. The continuous coating in WeTro spinning technology will produce composite yarns with improved interaction between the micro and the nanofiber layer.
[0005] Various discontinuous methods of developing electrospun yarn and core-shell type nanofibrous yarns have been attempted previously. For instance, U.S. Pat. No. 10094051 B1 discloses a method for producing a core-shell yarn using pre-spun yarn as the core and an umbrella-shaped electrode collector for the electrospun shell. Further, CN Pat. No. 104278345A discloses a method to develop skin core structure filament using a wire sandwich layer and polymer electrospinning to develop skin over the core. The aforementioned discoveries used a predeveloped core and then spun a nanofibrous coating over it.
[0006] Therefore, the present invention discloses a comprehensive system/apparatus and method for wet-electro spinning to fabricate nanofiber-coated polymer composite yarns. The novelty of the current invention is that it utilizes two fiber spinning techniques, i.e., wet spinning and electrospinning, to continuously develop the core fiber and the nanofibrous coating over it to produce composite yarn, in a single machine with enhanced interaction between the core and the surface coating. The coating is conducted when the substrate and the nanofiber are present in the liquid medium, thereby ensuring better adhesion and uniformity of the coating. It is physically advantageous and cost-effective to produce composite yarns using the invented WeTro spinning technology.

OBJECTS OF THE INVENTION
[0007] It is an object of the present disclosure which provide a wet-electro spinning system and method to fabricate nanofibers coated polymer composite yarns.
[0008] A further objective of the invention is to integrate wet-spinning and electrospinning processes within a single system to enable the simultaneous formation of a polymer core filament and deposition of functional nanofibers onto its surface, thereby producing composite yarns with enhanced mechanical, functional, and surface properties.
[0009] It is an object of the present disclosure to develop a versatile apparatus capable of processing a wide range of synthetic and natural polymers for both the core and nanofiber sheath, facilitating the production of customized composite yarns for applications in medical textiles, filtration, membrane, wearable sensors, smart fabrics, and advanced structural materials.

[0010] It is an object of the present invention is to provide a system and method for fabricating nanofiber coated polymer composite yarns wherein the coating of nanofibers onto the substrate is carried out at the liquid surface. This ensures enhanced adhesion, uniform deposition, and improved interfacial bonding between the core fiber and the nanofibrous layer, thereby resulting in mechanically robust and functionally superior composite yarns.

SUMMARY
[0011] The present disclosure is directed towards a wet-electro (WeTro) spinning system and method to fabricate nanofibers coated polymer composite yarns. The WeTro spinning system to fabricate nanofiber-coated substrates, comprising of a polymer feeder as a feed solution supply source; a spinneret for extruding feed solution to form a substrate; a collector filled with liquid media comprising an organic or inorganic solvent to receive the substrate; and a dispensing system for generating nanofibers from polymer solution, wherein the nanofibers are deposited directly onto the substrate at the liquid media surface. The system further comprises a drying nanofiber-coated substrate using a means for heating system.
[0012] The method of WeTro spinning for fabricating nanofiber-coated substrates, comprising of generating nanofibers by electrospinning through a dispensing system or melt; depositing the nanofibers directly onto a substrate at a liquid surface comprising an organic or inorganic solvent; and allowing the deposited nanofibers to form a nanofiber mat or coating on said substrate, wherein the nanofiber structure is obtained as a sheet, membrane, or tubular coating for imparting enhanced mechanical, electrical, or chemical functionality.
[0013] In an aspect of the present disclosure, the method is performed at ambient temperature, whereby dispensing system maintaining a flow rate ranging between 0.1–1 mL/h, with a nozzle diameter ranging between 0.2–1.5 mm, at a line speed ranging between 0.5–5 m/min, and at an applied voltage ranging between 5–30 kV.
[0014] In an aspect of the present disclosure, the substrate is a material with micro- to millimeter-level dimensions, thread, filament, or yarn, woven or non-woven fabric or a combination thereof, having an architecture selected from solid, hollow, flat ribbon, or a geometry determined by the spinneret configuration, and wherein the spinneret is configured in a custom shape, such as triangular, circular, or square.
[0015] In an aspect of the present disclosure, the polymer solution including atleast one polymer and atleast one solvent, wherein the atleast one polymer is selected from a natural or a synthetic polymer including, but not limited to, collagen, gelatin, chitosan, Poly-ε-caprolactone (PCL), Polyethylene glycol (PEG), silk, Cellulose acetate, Polyvinyl alcohol (PVA), Polyacrylonitrile (PAN), Polyvinyl diene fluoride (PVDF), Polyvinyl chloride (PVC) or a combination thereof, and wherein the atleast one solvent including, but not limited to, distilled water, Ethanol/water mixtures, Methanol, Dimethylformamide (DMF), Dimethyl sulfoxide (DMSO), Chloroform, Dichloromethane (DCM), Dimethylacetamide (DMAc), Tetrahydrofuran (THF), Acetone, Acetic acid, Formic acid, Trifluoroacetic acid (TFA), Hexafluoro isopropanol (HFIP) or a combination thereof.
[0016] In an aspect of the present disclosure, the polymer is a composite with fillers including, but not limited to, glass, carbon, mineral, fibers, drug, and metal oxide nano powder.
[0017] In an aspect of the present disclosure, the liquid media is selected from a non-corrosive/corrosive and non-hazardous media such as water, Ethanol, Isopropanol (IPA), DMF, Ethanol–water mixtures, Glycerol–water mixtures, PEG Solution, Mineral oil, Silicone oil, and mild salt solution in water or a combination thereof.
[0018] In an aspect of the present disclosure, the dispensing system having atleast one dispenser selected from a syringe pump with needle, needleless dispenser or pressure-controlled dispenser.
[0019] In an aspect of the present disclosure, the dispensing system is configured as a two-nozzle unit or as a multi nozzle array configured to deposit the nanofibers directly onto the substrate at the liquid-air interface.
[0020] In an aspect of the present disclosure, the dispensing system having a nozzle diameter ranging from 0.2 mm to 1.5 mm.
[0021] In an aspect of the present disclosure, the spinneret and the collector are separated by a predefined spacing with an adjustable air gap between the spinneret hole and the surface of the liquid media.
[0022] In an aspect of the present disclosure, the system further comprising a metering pump connected to the polymer feeder for controlling feeding rate, a roller setup inside the collector to receive the substrate, a non-conductive sheet to cover the collector, a voltage supply unit connected to the dispensing system, a take-up mechanism adapted to receive nanofiber-coated substrate from the collector, a heating chamber for drying the nanofiber-coated substrate, and a winding unit to form a polymer yarn spool from the nanofiber-coated substrate.

BRIEF DESCRIPTION OF THE DRAWINGS
[0023] The accompanying drawings are included to provide a further understanding of the present disclosure and are incorporated in and constitute a part of this specification. The drawings illustrate exemplary embodiments of the present disclosure and, together with the description, serve to explain the principles of the present disclosure.
[0024] FIG. 1 is a schematic representation of the WeTro spinning system.
[0025] FIG. 2 is a representation of nanofibers coated composite yarn developed by WeTro spinning.
[0026] FIG. 3 illustrates another embodiment of the WeTro spinning system.

DETAILED DESCRIPTION
[0027] Aspects of the present disclosure relate to a method and system for Wet-Electro (WeTro) spinning to fabricate nanofibers coated polymer composite yarns.
[0028] The following is a detailed description of embodiments of the disclosure. The embodiments are in such detail as to communicate the disclosure. However, the amount of detail offered is not intended to limit the anticipated variations of embodiments; on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the present disclosure as defined by the appended claims.
[0029] The present disclosure is directed towards a Wet-Electro spinning system and method to fabricate nanofibers coated polymer composite yarns. In an embodiment of the present disclosure, Figure 1 discloses a schematic representation of the WeTro spinning system. The system comprising of a polymer feeder (101) as a feed solution supply source; a spinneret (104) for extruding feed solution to form a substrate (110); a collector (106) filled with liquid media (108) comprising an organic or inorganic solvent to receive the substrate (110); and a dispensing system (111, 112, 120) for generating nanofibers (118) from polymer solution, wherein the nanofibers (118) are deposited directly onto the substrate (110) at the liquid media (108) surface.
[0030] In an embodiment of the present disclosure, method of wet-electro (WeTro) spinning for fabricating nanofiber-coated substrates, comprising of generating nanofibers (118) by electrospinning through a dispensing system (111, 112, 120) or melt; depositing the nanofibers (118) directly onto a substrate (110) at a liquid surface comprising an organic or inorganic solvent; and allowing the deposited nanofibers to form a nanofiber mat or coating on said substrate (110), wherein the nanofiber structure is obtained as a sheet, membrane, or tubular coating for imparting enhanced mechanical, electrical, or chemical functionality.
[0031] As shown in Figure 1, a polymer feeder (101) is connected to a metering pump (102), and a flow-controlling valve (103) is attached to a spinneret (104). The substrate/spun fiber/processed polymer (105) enters the collector/grounded coagulation tank (106) containing liquid media or coagulating liquid (108), and is collected by the roller setup (109). The coagulation bath (106) consists of a set of rollers/roller setup (109) with adjustable speeds, arranged at certain angles to receive the substrate/spun/extruded fiber (105). The coagulation tank (106) is covered with a non-conducting sheet (107), except at the fiber entry and exit points.
[0032] One or two other polymer solution feeding sources are attached to the tank, comprising a controlled polymer solution dispensing system (111 and 112) and a voltage supply unit/high-voltage supply (113). The wet spun fiber (110), before leaving the coagulation tank (106), gets coated by the nanofibers being developed on the surface of the coagulating liquid (108), through the polymer solution dispensing systems (111 and 112), attached to the high voltage supply (113). The deposition of the polymer solution results in the generation of nanofibers (118) on the substrate surface at the liquid-solid interface. The electrospun nanofibers solidify in air, and then interact with the liquid bath, and therefore are formed at the liquid-solid interface.
[0033] The nanofiber-coated substrate or the nanofibers-coated composite yarn (114) is then passed on to the heating chamber (115) and then finally to the winding unit (116). The system is enclosed in a safety cabinet. A take-up roller assembly is followed by a means for heating, such as a temperature-controlled heating chamber (115) attached to the winding unit (116) to produce the coated fiber spool.
[0034] In an embodiment of the present disclosure, a method of wet-electro spinning to fabricate nanofibers coated polymer composite yarns is disclosed. The method of producing a nanofibrous coating over the freshly wet spun fiber, comprising, polymer solution loading into the polymer feeder (101), controlling the solution flow by metering pump (102) with a flow-controlling valve (103), and extrusion into the coagulation bath (106) through spinneret (104) of specific extrusion diameter. The rollers (109) in the coagulation bath (106), rotating at specific speeds, receive the fiber, stretch it, and subject it to the other polymer solution sources while exiting the coagulation bath tank (106). The polymer dispenser/jet emerging from the controlled dispensing systems (111, 112) attached to the high voltage supply (113) forms a nanofibrous layer over the coagulation solvent that is subsequently coated over the fiber surface at the liquid-solid interface. The nanofibers settle loosely in the liquid, forming a thick 3D sponge-like network. The so-formed polymer yarn is received by the take-up rollers that pass it through the heated chamber (115) for drying and finally gets wound on a spool by the winding unit (116).
[0035] In an embodiment of the present disclosure, the spinneret (104) is submerged in the ground coagulation bath/tank (106). In another aspect of the system, the spinneret (104) is at a certain height from the grounded coagulation bath/tank (106) with an adjustable air gap between the spinneret hole and the surface of the fluid in the coagulation bath (106).
[0036] In an embodiment of the present disclosure, the core is a wet-spun core fiber (117) and the surface is covered with nanofibers or electrospun nanofibers (118), forming composite yarn as depicted in Figure 2.
[0037] In an embodiment of the present disclosure, as shown in Figure 3, the system/apparatus includes a grounded wire electrode (119) and the two polymers dispensing systems (120), which are directly coat the nanofibers on the freshly wet spun fiber (121) after it leaves the coagulation tank (106).
[0038] In an embodiment of the present disclosure, the substrate (110) is a material with micro- to millimeter-level dimensions, thread, filament, or yarn, woven or non-woven fabric or a combination thereof, having an architecture selected from solid, hollow, flat ribbon, or a geometry determined by the spinneret (104) configuration, and wherein the spinneret (104) is configured in a custom shape, such as triangular, circular, or square. Commonly used substrates include Polypropylene (PP) yarn or nonwoven fabric. In an embodiment of the present disclosure, the yarn diameter can be 0.3-1 mm, the fabric width can be 20–250 mm, the length can be 10–1000 meters (continuous roll-to-roll coating), and the weight can be 10–100 g/m².
[0039] In an embodiment of the present disclosure, the polymer solution includes atleast one polymer and atleast one solvent. The polymer can be any synthetic or natural polymer, including, but not limited to, collagen, gelatin, chitosan, poly-ε-caprolactone (PCL), polyethylene glycol (PEG), silk, Cellulose acetate, polyvinyl alcohol (PVA), polyacrylonitrile (PAN), Polyvinyl diene fluoride (PVDF), polyvinyl chloride (PVC), etc. The polymer can be a composite with fillers including, but not limited to, glass, carbon, mineral, fibers, drug, metal oxide nanopowder, etc. The fiber architecture is a solid, hollow, flat ribbon, or any other shape determined by the spinneret geometry.
[0040] In an embodiment of the present disclosure, the solvent includes, but not limited to, distilled water, Ethanol/water mixtures, Methanol, Dimethylformamide (DMF), Dimethyl sulfoxide (DMSO), Chloroform, Dichloromethane (DCM), Dimethylacetamide (DMAc), Tetrahydrofuran (THF), Acetone, Acetic acid, Formic acid, Trifluoroacetic acid (TFA), Hexafluoro isopropanol (HFIP) or a combination thereof etc.
[0041] In an embodiment of the present disclosure, the liquid media (108) is coagulating solvent/non-solvent for the liquid collector (106) which includes an organic or inorganic solvent or non-corrosive/corrosive and non-hazardous solvents like Water (Distilled/Deionized), Ethanol (absolute or 70%), Isopropanol (IPA), DMF, Ethanol–Water Mixtures, Glycerol–Water Mixtures, Polyethylene glycol (PEG) Solution, Mineral Oil / Silicone Oil, and mild salt solution in water.
[0042] In an embodiment of the present disclosure, the spinneret (104) contains a nozzle in which the nozzle diameter is variable for all architectures, solid and hollow. The spinneret geometry can be altered to any shape according to the requirements, i.e., triangular, circular, square, etc.
[0043] In an embodiment of the present disclosure, the temperature of the system is controllable according to the process condition requirements. The number of rollers in the roller setup (109) inside the coagulation bath (106) is variable, containing at least 1 roller. The speed of the rollers is adjustable.
[0044] In an embodiment of the present disclosure, the number of dispensers can be dual or multiple in the controlled dispensing systems (111, 112). The dispenser can be of different types, e.g., syringe pump with needle or needleless or pressure controlled, etc., in the controlled dispensing system (111, 112). The dispenser can coat nanofibres either via deposition on the surface of the fluid (108) in the tank (106) or directly onto the wet-spun fiber (110). The number of syringes in the dispenser with the syringe pump can be single or multiple.
[0045] The dispensing system (111, 112, 120) is configured as a two-nozzle unit or as a multi-nozzle array (2–100) for large-scale production. The dispensing system (111, 112, 120) is configured to deliver the polymer solution onto the substrate (105) positioned in contact with the liquid media (108). The deposition of the polymer solution results in the generation of nanofibers (118) on the substrate surface at the liquid-solid interface. The temperature of the grounded coagulation bath/tank (106) is controlled. The solvent in the grounded coagulation bath/tank (106) can be any fluid as per the polymers used in spinning. The temperature in the heating chamber (115) is variable as per the requirements.
[0046] In a preferred embodiment, the WeTro spinning is conducted under ambient temperature conditions. The voltage range is between 5-30 kV, preferably 12 kV. The process line speed varies from 0.5 to 5 m/min. The flow rate is usually low i.e. 0.1–1 mL/h, preferably 0.5 ml/h to maintain stable jet formation. The nozzle-to-collector (106) distance is often 10–20 cm to allow solvent evaporation before hitting the bath (106). The polymer solution feeding is done by a syringe pump. The nozzle diameter ranges between 0.2 mm to 1.5 mm. The fabricated yarn diameter is preferably 0.3-1 mm.
EXEMPLARY EMBODIMENT
[0047] A polymer solution comprising 8% w/v Polyacrylonitrile (PAN, Mw ~100,000 g/mol) was prepared by dissolving the polymer in Dimethylformamide (DMF). The mixture was stirred using a magnetic stirrer on a hot plate at 40 °C and 400 RPM for at least 6 hours to ensure complete dissolution. The resulting homogeneous solution was loaded into a 5 mL disposable syringe fitted with a 23-gauge needle. Electrospinning was carried out using a syringe pump set at a flow rate of 0.5 mL/h to maintain a stable jet. A high voltage of 12.5 kV was applied across a 12 cm distance between the needle tip and the collector. The collector consisted of a water bath, allowing partial solvent evaporation before fiber deposition. A rotating yarn submerged in the bath served as the collection substrate, enabling uniform coating of electrospun nanofibers onto its surface. The nanofiber-coated yarn was subsequently drawn by a take-up roller and wound onto a spool. The final coated yarn exhibited a uniform diameter of approximately 0.5 mm.

APPLICATIONS
[0048] Applications of WeTro technology includes:
• Filtration & Separation: 3D porous nanofiber mats suitable for air, oil–water, and liquid filtration.
• Drug Delivery: High surface area matrices for controlled release systems
• Wound Care: Absorbent, breathable, biocompatible dressings.
• Smart Textiles: Functionalized, breathable fabric systems with integrated nanostructures.

[0049] The present invention provides a novel spinning system/apparatus and method (WeTro spinning) that enables the continuous production of fiber composite yarn by integrating wet-spinning and electrospinning. This process allows uniform nanofiber coating over micro-sized wet-spun fibers, resulting in enhanced composite yarns with potential applications across advanced technical textiles, biomedical, and functional/smart material industries. The nanofibers-coated composite yarns developed through WeTro spinning technology can be used for a variety of applications in the fields of technical textiles, biomedical, filtration, energy harvesting, defense, packaging, etc.

[0050] While the foregoing describes various embodiments of the invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof. The scope of the invention is determined by the claims that follow. The invention is not limited to the described embodiments, versions, or examples, which are included to enable a person having ordinary skill in the art to make and use the invention when combined with information and knowledge available to the person having ordinary skill in the art.
, C , Claims:We Claim:
1. A method of wet-electro (WeTro) spinning for fabricating nanofiber-coated substrates, comprising of:
(a) generating nanofibers (118) by electrospinning of polymer solution through a dispensing system (111, 112, 120) or polymer melt;
(b) depositing the nanofibers (118) directly onto a substrate (110) at a liquid surface comprising an organic or inorganic solvent; and
(c) allowing the deposited nanofibers to form a nanofiber mat or coating on said substrate (110),
wherein the nanofiber structure is obtained as a sheet, membrane, or tubular coating for imparting enhanced mechanical, electrical, or chemical functionality.
2. The method of WeTro spinning as claimed in claim 1, wherein the depositing the nanofibers (118) directly onto the substrate (110), which is a material with micro- to millimeter-level dimensions, thread, filament, or yarn, woven or non-woven fabric, or a combination thereof.
3. The method of WeTro spinning as claimed in claim 1, wherein the depositing the nanofibers (118) directly onto the substrate (110) at the liquid surface or a liquid media (108) selected from a non-corrosive/corrosive and non-hazardous media such as water, Ethanol, Isopropanol (IPA), DMF, Ethanol–water mixtures, Glycerol–water mixtures, PEG Solution, Mineral oil, Silicone oil, and mild salt solution in water or a combination thereof.
4. The method of WeTro spinning as claimed in claim 1, wherein the method further comprises drying a nanofiber-coated substrate (114) using a means for heating system (115).
5. The method of WeTro spinning as claimed in claim 1, wherein the method is performed at ambient temperature, whereby dispensing system (111, 112, 120) maintaining a flow rate ranging between 0.1–1 mL/h, with nozzle diameter ranging between 0.2–1.5 mm, at a line speed ranging between 0.5–5 m/min, and at an applied voltage ranging between 5–30 kV.
6. A wet-electro (WeTro) spinning system to fabricate nanofiber-coated substrates, comprising of:
a polymer feeder (101) as a feed solution supply source;
a spinneret (104) for extruding feed solution to form a substrate (110);
a collector (106) filled with liquid media (108) comprising an organic or inorganic solvent to receive the substrate (110); and
a dispensing system (111, 112, 120) for generating nanofibers (118) from polymer solution or polymer melt, wherein the nanofibers (118) are deposited directly onto the substrate (110) at the liquid media (108) surface.
7. The WeTro spinning system as claimed in claim 6, wherein the substrate (110) is a material with micro- to millimeter-level dimensions, thread, filament, or yarn, woven or non-woven fabric or a combination thereof, having an architecture selected from solid, hollow, flat ribbon, or a geometry determined by the spinneret (104) configuration, and wherein the spinneret (104) is configured in a custom shape, such as triangular, circular, or square.
8. The WeTro spinning system as claimed in claim 6, wherein the polymer solution including atleast one polymer and atleast one solvent, wherein the atleast one polymer is selected from a natural or a synthetic polymer including, but not limited to, collagen, gelatin, chitosan, Poly-ε-caprolactone (PCL), Polyethylene glycol (PEG), silk, Cellulose acetate, Polyvinyl alcohol (PVA), Polyacrylonitrile (PAN), Polyvinyl diene fluoride (PVDF), Polyvinyl chloride (PVC) or a combination thereof, and wherein the atleast one solvent including, but not limited to, distilled water, Ethanol/water mixtures, Methanol, Dimethylformamide (DMF), Dimethyl sulfoxide (DMSO), Chloroform, Dichloromethane (DCM), Dimethylacetamide (DMAc), Tetrahydrofuran (THF), Acetone, Acetic acid, Formic acid, Trifluoroacetic acid (TFA), Hexafluoro isopropanol (HFIP) or a combination thereof.
9. The WeTro spinning system as claimed in claim 8, wherein the polymer is a composite yarn with fillers including, but not limited to, glass, carbon, mineral, fibers, drug, and metal oxide nano powder.
10. The WeTro spinning system as claimed in claim 6, wherein the liquid media (108) is selected from a non-corrosive/corrosive and non-hazardous media such as water, Ethanol, Isopropanol (IPA), DMF, Ethanol–water mixtures, Glycerol–water mixtures, PEG Solution, Mineral oil, Silicone oil, and mild salt solution in water or a combination thereof.
11. The WeTro spinning system as claimed in claim 6, wherein the dispensing system (111, 112, 120) having at least one dispenser selected from syringe pump with needle, needleless dispenser or pressure-controlled dispenser.
12. The WeTro spinning system, as claimed in claim 6, wherein the dispensing system (111, 112, 120) is configured as a two-nozzle unit or as a multi-nozzle array configured to deposit the nanofibers (118) directly onto the substrate (110) at a liquid-air interface.
13. The WeTro spinning system, as claimed in claim 6, wherein the dispensing system (111, 112, 120) having a nozzle diameter ranging from 0.2 mm to 1.5 mm.

14. The WeTro spinning system, as claimed in claim 6, wherein the system further comprises a controlled heating chamber (115) for drying the nanofiber-coated substrate (114).