GB2596079A - Layered polymer nanocomposite and method of manufacture thereof - Google Patents

Abstract

The layered polymer nanocomposite 100 comprises graphene nanoplatelets 104 dispersed in and stabilized with a polymer matrix 102 and a third-party material 106 having a non-zero band gap value. The 3rd party material 106 is preferably molybdenum disulphide, diamond, silicon, silicon dioxide, silicon nitride, silicon carbide, gallium nitride, gallium phosphate, gallium arsenide, lead sulphide, copper oxide, magnesium oxide, zinc oxide, titanium oxide, aluminium nitride, aluminium gallium nitride, aluminium gallium oxide, cubic boron nitride, germanium or piezoelectric ink. The polymer is preferably polyvinyl butyral, styrenic or acrylic. The nanocomposite is used in semi-permanent, anti-microbial, anti-viral and anti-abrasive coatings for door handles or tables, medical devices, remoulded products or on an assay substrate. The nanocomposite 100 is formed by transferring a third-party material 106 onto a substrate comprising graphene 104 in a polymeric binder 102 to form a circuit-primed substrate and then adding a seal layer onto the other surface.

Description

LAYERED POLYMER NANOCOMPOSITE AND METHOD OF MANUFACTURE

THEREOF

TECHNICAL FIELD

The present disclosure relates generally to surface coatings, and more specifically, to layered polymer nanoconnposites comprising a polymer matrix, graphene nanoplatelets dispersed therein and a third-party material having a non-zero band gap value. Moreover, the present disclosure is concerned with methods of manufacturing aforementioned layered polymer nanocomposite.

BACKGROUND

The latest global pandemic COVID-19 and earlier epidemics have raised a major concern regarding the health management and sanitation conditions globally. The spread of infection caused by viruses, bacteria, protozoans and other microorganisms may be attributed to poor hygiene and sanitation conditions. Majority of such infections have proved to be fatal in a large proportion of the world population, such as for example COVID-19. Conventional measures for controlling further spread of infectious disease includes sanitation, social distancing and immunity boosting. However, said measures fail at different levels of interactions.

Conventional techniques for sanitation include hand sanitizers, surface sanitizers, disinfectants, soaps, and so forth. Routine sanitation practices comprise application or spray of multi-litres of sanitation solutions to a potential infected area. However, such routine sanitation works fail to disinfect frequently accessed everyday use articles, such as door handles, tables and the like. Such high impact touch points for humans help drive the epidemic at an uncontrolled pace. Moreover, production and supply of sanitizing solutions is limited and is highly dependent on the jurisdictional regulations. Furthermore, increasing demand of sanitizing solutions may eventually lead to an exponential increase in the price thereof.

With the advancement in polymer science, easy to clean surfaces have been developed for various applications. Various polymers have been used solely or mixed with suitable additives to produce articles that prevents dust, water or oil to accumulate thereon and are easy to clean, for example fans, air conditioners, chimneys, and so on. The labs, hospitals, offices and houses are equipped with furniture and appliances that are easy to clean. However, current methods of manufacturing such articles have many limitations in terms of cost, efficiency, quality, and environmental consequences (for example reduced degradation rate, incompatibility with current recycling scheme, toxicity, and so on). Moreover, easy cleaning fails to guarantee complete disinfection of the surfaces, especially from microbes and/or viruses. Furthermore, it is not convenient to clean the surfaces of the everyday use articles every time before reusing or accessing them.

Recent advances in nanotechnology and polymer sciences have introduced nano-to microscale additives, such as graphene oxide, to impart mechanical strength to the plastics and enhance other properties such as thermal and electrical conductivity, etc. Moreover, graphene oxide has been chemically modified to increase the stability (with polymers), solubility (in water and gases), and conductivity (creating a suitable band gap) thereof. However, conventional methods of modifying graphene sheets have many limitations in terms of efficiency, cost, quality, and structural and functional defects, thereby defeating the purpose of graphene in plastics.

Therefore, in light of the foregoing discussion, there exists a need to overcome the aforementioned drawbacks associated with conventional polymer nanocomposites and methods of manufacture thereof.

SUMMARY

The present disclosure seeks to provide a layered polymer nanocomposite. The present disclosure also seeks to provide a method of manufacturing the aforementioned layered polymer nanocomposite. The present disclosure seeks to provide a solution to the existing problem of stabilizing graphene with a polymer and developing and transferring nanocircuits within the layers of graphene-polymer nanocomposite. The present disclosure further seeks to provide an easy to peel off protective surface coating layer for everyday use surfaces like handles and the like. Moreover, the layered polymer matrix enables efficient identification, disinfection and repeated access of surfaces infected with microorganisms, such as bacteria, viruses including COVID-19, and so on.

In one aspect, an embodiment of the present disclosure provides a layered polymer nanocomposite comprising: a polymer matrix; - graphene nanoplatelets dispersed in the polymer matrix, wherein the graphene nanoplatelets are stabilized with the polymer matrix; and - a third-party material having a non-zero band gap value.

An aim of the present disclosure is to provide a solution that overcomes at least partially the problems encountered in prior art, and to provide a novel, inexpensive and highly efficient surface coating layers that are antimicrobial, anti-abrasive, durable, sustainable, light-weight, thin, flexible, water repellent, transparent, extremely robust, reusable; moreover allows energy and information to be transferred. Furthermore, the layered polymer nanocomposite (namely tri-layer semi-permanent coating) comprising stabilized graphene nanoplatelets improves the longevity, robustness and usability of the surfaces coated with the layered polymer nanocomposite.

Optionally, the polymer matrix comprises vinylic, styrenic or acrylic polymer, and wherein the vinylic polymer is a polyvinyl butyral.

Optionally, the third-party material is selected from a group comprising: molybdenum disulfide, carbon (diamond), silicon, silicon dioxide, silicon nitride, silicon carbide, gallium nitride, gallium phosphide, gallium arsenide, lead sulfide, copper oxide, magnesium oxide, zinc oxide, titanium oxide, aluminium nitride, aluminium gallium nitride, aluminium gallium oxide, cubic-boron nitride, germanium, piezoelectric ink.

Optionally, the layered polymer nanocomposite is used in any of: semipermanent coatings, anti-microbial coatings, anti-viral coatings, medical devices, anti-abrasive coatings, remolded products, surfaces, wherein the semi-permanent coating is removable.

Optionally, the layered polymer nanocomposite further comprises an assay substrate, wherein a change in the assay substrate is correlated with the presence of a microorganism.

In another aspect, an embodiment of the present disclosure provides a method of manufacturing a layered polymer nanocomposite, the layered polymer nanocomposite comprising: - a polymer matrix; - graphene nanoplatelets dispersed in the polymer matrix, wherein the graphene nanoplatelets are stabilized with the polymer matrix; and - a third party material having non-zero band gap value, wherein the method comprises: a) dispersing the graphene nanoplatelets in the polymer matrix to form a substrate layer having a first side and a second side; b) transferring a third-party material on the first side of the substrate layer to form a circuit-primed substrate layer having an open side; and c) adding a seal layer on the open side of the circuit-primed substrate layer to form the layered polymer nanoconnposite.

Embodiments of the present disclosure substantially eliminate or at least partially address the aforementioned problems in the prior art, and provides a tri-layer polymer nanocomposite with improved mechanical performance (both toughness and flexibility) combined with superior antimicrobial, anti-viral and bacteriostatic properties, thermal and electrical conductivity, resistance to thermal degradation, optical, and biosensing properties.

Additional aspects, advantages, features and objects of the present disclosure would be made apparent from the drawings and the detailed description of the illustrative embodiments construed in conjunction with the appended claims that follow.

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.

BRIEF DESCRIPTION OF DRAWINGS

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 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: FIG. 1 shows a schematic illustration of a layered polymer nanocomposite, in accordance with an embodiment of the present disclosure; and FIG. 2 is an illustration of steps of a method of manufacturing a layered polymer nanocomposite, in accordance with an embodiment of the present disclosure.

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

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 practising the present disclosure are also possible.

The present disclosure provides the aforementioned layered polymer nanocomposite with improved mechanical performance (both flexibility and toughness). Graphene is a good conductor of heat and electricity, therefore, the layered polymer nanocomposite allows energy and information to be transferred therein. The disclosed layered polymer nanocomposite is highly efficient as a surface coating agent with a high sustainable product lifecycle combined with superior electrical conductivity and biosensing properties. The anti-microbial and anti-viral properties, attributed to graphene, enables immediate detection and analysis of the microorganisms, such as the current COVID-19 on high impact touch points, such as door handles, that help drive the epidemic in human population. Furthermore, the layered polymer nanocomposite is used as an anti-abrasive coating, layers of which are held intact even at conditions of extreme mechanical stress. Beneficially, the layered polymer nanocomposite is applied on surfaces as a semi-permanent coating and is easy to apply and easy to peel off, thus proving for a surface easy to remove and protection from being infected with COVID19, other viruses, or bacteria. Moreover, said coating is flexible and can be applied on articles with uneven shapes and surfaces. Additionally, beneficially, the layered polymer nanocomposite provides an environment-friendly alternative to conventional plastics, and may be exploited in niche applications employing recyclable or biodegradable materials.

Referring to FIG. 1, shown is a schematic illustration of a layered polymer nanocomposite 100, according to an embodiment of the present disclosure. The layered polymer nanocomposite 100 comprises a polymer matrix 102; graphene nanoplatelets 104 dispersed in the polymer matrix, wherein the graphene nanoplatelets 104 are stabilized with the polymer matrix 102; and a third-party material 106 having a non-zero band gap value.

Throughout the present disclosure, the term "layered polymer nanocomposite" as used herein refers to an artificially-made material having coating or covering properties. Notably, the layered polymer nanocomposite 100 can be employed for a variety of applications such as the decorative, functional or both. Specifically, the layered polymer nanocomposite 100 is applied as a coating on (or covering over) a surface of an article. More specifically, the layered polymer nanocomposite 100 may be an all-over coating (i.e. completely covering the article) or a partial coating (i.e. partly covering the article). The layered polymer nanocomposite 100 may be coated by various processes known in the art.

The layered polymer nanoconnposite 100 comprises a polymer matrix 102. Throughout the present disclosure, the term "polymer matrix" as used herein refers to a synthetic, polymeric, viscous compound (composition or substance) that provides the continuous (bulk) phase of dispersion. Optionally, the polymer matrix 102 comprises vinylic, styrenic or acrylic polymer, and wherein the vinylic polymer is a polyvinyl butyral. In other words, the polymer matrix 102 comprises chemicals having structural elements based respectively on a vinyl moiety, styrene or an acrylic moiety. Optionally, the styrenic monomer is styrene, the acrylic monomer is methyl acrylate, methyl methacrylate, ethylene glycol, ethylene oxide, and so on, and the vinylic monomer is ethylene, propylene or substituted ethylene or propylene.

Optionally, the polymer matrix 102 includes, but is not limited to, polyacrylates, polynnethylmethacrylates, polylactic acid (PLA) polymers, polyhydroxyalkanoate (PHA) polymers (e.g., polyhydroxybutyrate (PHB)), polycaprolactone (PCL) polymers, polyglycolic acid polymers, acrylonitrile-butadiene-styrene polymers (ABS), vinyl polymers (such as polyvinyl alcohol (PVA, polyvinyl butyral (PVB), polyvinyl chloride (PVC), polyethylene, polypropylene, and the like), polyurethane polymers, polyester polymers, and polyamide polymers. In an example, the polymer matrix 102 is polyvinyl butyral (PVB). Beneficially, polyvinyl butyral (PVB) provides toughness, flexibility, strong binding, optical clarity and enhanced adhesion to various surfaces.

Moreover, the layered polymer nanoconnposite 100 comprises the graphene nanoplatelets 104 dispersed in the polymer matrix 102. Throughout the present disclosure, the term "graphene" refers to a honeycomb planar film formed by sp2 hybridization of carbon atoms, also called graphite. Optionally, graphene may be synthesised by one of the synthesis techniques: mechanical cleaving, chemical exfoliation, chemical synthesis or chemical vapour deposition. In mechanical cleaving technique, graphite or graphene oxide is mechanically exfoliated to obtain graphene sheets. Furthermore, the properties and structure of graphene may depend on the technique employed for synthesis. Beneficially, the chemical vapour deposition technique may be employed to obtain graphene sheets with the least amount of impurities.

Typically, the graphene nanoplatelets 104 are short stacks of polygonal platelet-shaped graphene sheets in a planar (2D) structure. Due to its unique size and morphology (honeycomb pattern), graphene is the world's thinnest, strongest and stiffest material. Furthermore, graphene nanoplatelets 104 possess enhanced barrier properties, excellent mechanical properties such as toughness, strength, and surface hardness, antimicrobial and antiviral properties, and excellent conductivity (both electrical and thermal).

Optionally, each of the graphene nanoplatelets 104 has a thickness in a range of 1-10 nanonnetres and a diameter in a range of 0.5-50 nnicrometres. In an example, the thickness may be from 1, 2, 3, 4, 5, 6, 7, 8 or 9 nanonnetres (nnn) up to 2, 3, 4, 5, 6, 7, 3, 9 or 10 nnn and the diameter may be from 0.5, 0.6, 0.7, 0.8, 0.9, 1, 5, 10, 15, 20, 25, 30, 35, 40 or 45 micronnetres (pm) up to 0.6, 0.7, 0.8, 0.9, 1, 5, 10, 15, 20, 25, 30, 35, 40, 45 or 50 pm. Beneficially, the smaller graphene nanoplatelets 104 move or turn more easily (laterally) in a dispersion media, such as the polymer matrix 102 (ranging from an average viscosity to a slightly higher viscosity). Consequently, such smaller graphene nanoplatelets 104 form continuous (or approximately continuous) sheet in the polymer matrix 102.

Optionally, the layered polymer nanocomposite 100 has a graphene nanoplatelets 104 content in a range between 0.10/0 and 100/0 by weight.

In an example, the graphene nanoplatelets 104 content in the layered polymer nanocomposite 100 is typically from 0.1, 0.5, 1 or 5% up to 0.5, 1, 5 or 10°A) by weight. Beneficially, the presence of the graphene nanoplatelets 104 in the polymer matrix 102 helps the layered polymer nanocomposite 100 achieve excellent mechanical strength as well as significantly improved thermal and electrical conductivity.

Moreover, the graphene nanoplatelets 104 are dispersed in the polymer matrix 102 using the various processes of dispersion known in the art. Specifically, the process of dispersion results in dispersing graphene nanoplatelets 104 in a stabilizing polymer matrix 102, such as PVB, to produce a polymer-stabilized graphene nanoplatelet dispersion. The term "stabilized" as used herein refers to a higher concentration of graphene nanoplatelets 104 dispersed in the polymer matrix 102. In this regard, the polymer matrix 102, preferably in a liquid form, is spread over a platform, for example, a glass substrate (such as polytetrafluoroethylene (PTFE) film on top of a glass, silicone-coated glass substrate, a PTFE glass mesh, a PEEK-coated glass substrate, and the like). The graphene nanoplatelets 104, are dispersed by continuous stirring in said polymer matrix 102. The dispersed graphene nanoplatelets 104 interact with the polymer matrix 102 for a predefined period of time (for example, ranging from 5 minutes to a few hours) at predefined temperature (for example room temperature). The dispersion of graphene nanoplatelets 104 in the polymer matrix 102 produces a uniform and fine distribution of graphene nanoplatelets 104 inside and on the surface of the polymer matrix 102. Consequently, the resultant layered polymer nanocomposite 100 achieves enhanced stability, mechanical strength and optical, thermal and electrical properties attributed to the individual components thereof. Optionally, the resultant layered polymer nanocomposite 100 is then filtered and washed.

Optionally, a suitable dispersion media is incorporated in the polymer matrix 102 to facilitate dispersion of the graphene nanoplatelets 104 in the polymer matrix 102. The suitable dispersion media may be a liquid at room or elevated temperatures (for example polyethylene glycol ether, castor oil, vegetable wax and water) or a solid (for polymers, glasses, metals, metal oxides and so forth.

Optionally, the graphene nanoplatelets 104 are suitably treated, for example with an activating agent, to facilitate dispersion of the graphene nanoplatelets 104 in the polymer matrix 102. Suitable activating agents may be selected from a group comprising alkyl amine, aromatic amines, functionalized amines, alkyl alcohols or other nucleophilic entities, thionyl chloride, Benzotriazol-1-yloxytris[dimethylamino]phosphoniunn hexafluorophosphate (BOP), 3-diethyoxyphosphoryloxy-1,2,3-benzotriazin-4(3H)-one (DEPBT), N,N'-Dicyclohexylcarbodiimide, N,N'-Diisopropylcarbodiimide, 4-(4,6-dinnethoxy-1,3,5-triazin-2-y1)-4-nnethylmorpholinium chloride (DMTMM), 1-[bis(dimethylamino)methylene]-1H-1,2,3-triazolo[4,5-b]pyridinium -3-oxide (HATU), 2-(1H-benzotriazol-1-y1)-1,1,3,3-tetramethyluronium hexafluorophosphate (HBTU), 1H-(6-chlorobenzotriazol-1-y1)-1,1,3,3-tetramethyluroniunn hexafluorophosphate (HCTU), 1-Hydroxy-7-azabenzotriazole, Hydroxybenzotriazole, (7-azabenzotriazol-1-yloxy)tripyrrolidinophosphoniunn hexafluorophosphate (PyA0P) reagent, (benzotriazol-1-yloxy)tripyrrolidinophosphonium hexafluorophosphate (PyBOP) and Thiocarbonyldiimidazole, and the like.

Furthermore, the layered polymer nanoconnposite 100 comprises the third-party material 106 having a non-zero band gap value. The term "band gap" as used herein refers to energy difference between different energy states of a solid material (for example conductor, semiconductor and insulator). The different energy states range between the top of the valence band and the bottom of the conduction band in insulators and semiconductors. Typically, the band gap is the energy required to promote an atom-bound valence electron to become a freely-movable conduction electron that serves as a charge carrier to conduct electric current. Therefore, electrical conductivity of a solid is based on its band gap value. A solid material, i.e. insulators, semiconductors and conductors, may possess larger band gaps, smaller band gaps and no or very small band gaps due to overlapping bands, respectively. Notably, the semiconductors behave as an insulator at absolute zero but allow thermal excitation of electrons at temperatures below the melting point thereof.

Optionally, the third-party material 106 is a semiconductor possessing a non-zero small band gap value. Optionally, the third-party material 106 is selected from a group comprising: molybdenum disulfide, carbon (diamond), silicon, silicon dioxide, silicon nitride, silicon carbide, gallium nitride, gallium phosphide, gallium arsenide, lead sulfide, copper oxide, magnesium oxide, zinc oxide, titanium oxide, aluminium nitride, aluminium gallium nitride, aluminium gallium oxide, cubic-boron nitride, germanium, piezoelectric ink. In an example, the third-party material 106 is molybdenum disulphide (Mo52). The crystal structure of Mo52 is a two-dimensional sheet comprising hexagonal plane of sulfur (5) atoms on either side of hexagonal plane of Molybdenum (Mo) atoms. Triple layers of two-dimensional Mo52 sheet may be stacked on top of each other with strong covalent bonds between the Mo and S atoms but weak van der Waals forces between the layers. However, individual layers of Mo52 results in formation of direct band gaps with an increased energy of approximately 1.8 to 1.9 electron volt (eV). Beneficially, due to its structure and direct band gap, MoS2 possesses excellent mechanical strength, electrical conductivity and can emit light and therefore is employed in several applications including, but not limited to, photodetectors, optical sensors, field-effect transistors (FET), biosensors and potential device applications (such as microelectronics and photoelectrochemical devices).

Typically, Mo52 has a layered structure same or similar to graphene.

Other graphene-like material is selected from a group comprising functionalized graphene, doped graphene, graphene oxide, partially reduced graphene oxide, graphite flakes, molybdenum diselenide (MoSe2), molybdenum ditelluride (MoTe2), tungsten disulfide (WS2), tungsten diselenide (WSe2), hexagonal boron nitride (h-BN), gallium sulfide (Gas), gallium selenide (GaSe), lanthanum cuprate (La2Cu04), bismuth tritelluride (Bi2Te3), bismuth triselenide (Bi2Se3), antimony triselenide (Sb25e3), zinc oxide (Zn0), niobium disulfide (NbS2), niobium diselenide (NbSe2), tantalum disulfide (TaS2), vanadium disulfide (VS2), rhenium disulfide (ReS2), rhenium diselenide (ReSe2), titanium disulfide (TS2), titanium diselenide (T5e2), indium trisulfide (InS), zirconium disulfide (Zr52), cadmium selenide (CdSe). Additionally or alternatively, the third-party material 106 is a piezoelectric ink or a carbon nanotubes.

Optionally, a tri-layer semi-permanent coating is manufactured using the layered polymer nanoconnposite 100 or obtained by performing the method of manufacturing the layered polymer nanocomposite 100 (as described in detail hereinbelow). Optionally, the tri-layer semi-permanent coating is manufactured from the layered polymer nanoconnposite 100 using an electrically-assisted three-dimensional (3D) printing process. Typically, the printing process takes place in a tank, such as a glass tank. The polymer matrix 102 in a fluid form is spread over the glass tank. The graphene nanoplatelets 104 are dispersed in the polymer matrix 102. The polymer-stabilized graphene nanoplatelet dispersion results in a substrate layer 108. The substrate layer 108 comprises a first side 108A and a second side 108B. Similar, to the substrate layer 108, a seal layer 110, comprising a polymer-stabilized graphene nanoplatelet dispersion, is produced. The seal layer 110 also comprises a first side 110A and a second side 110B. Optionally, the graphene nanoplatelets 104 dispersed in the polymer matrix 102 may be subjected to an electric current, for example, a direct-current voltage of 1300 V, to generate the electric field of 433 V/cnn to polarically align the graphene nanoplatelets 104 in the polymer matrix 102. Optionally, the graphene nanoplatelets 104 are vertically aligned, like pyramids stacking up, thus inducing hydrophobicity in the substrate layer 108 and the seal layer 110. Optionally, the graphene nanoplatelets 104 polarically aligned in the polymer matrix 102 is photocured by exposure to light, such as ultraviolet light. Optionally, the photocured graphene nanoplatelets 104 is processed to remove non-conductive binders and welded together to enhance conductivity of the obtained tri-layer semi-permanent coating. Optionally, the post-printing process involves, heat, chemical, electrical or rapid-pulse laser treatment that processes graphene nanoplatelets 104 without damaging the printing surface, such as a paper, or glass substrate. Subsequently, the third-party material 106 having a non-zero band gap value is inserted between the substrate layer 108 and the seal layer 110. Optionally, the third-party material 106 is transferred to the substrate layer 108 to form a circuit-primed substrate layer, and the seal layer 110 is added (or attached) on to the circuit-primed substrate layer to for the tri-layer semi-permanent coating. Optionally, the third-party material 106 is etched on a graphene nanoplatelet directly before insertion between the substrate layer 108 and the seal layer 110. Alternatively, optionally, the third-party material 106 is printed on a paper using techniques known in the art (such as laser techniques and nano processing techniques) and subsequently transferred to gra phene nanoplatelet via heat process before insertion as discussed above. It will be appreciated that the excess paper may be removed and the circuit primed.

Optionally, the tri-layer semi-permanent coating is manufactured from the layered polymer nanocornposite 100 using a graphene printing technology. The graphene printing technology uses a customized inkjet printer to print with graphene nanoplatelet 104 flakes, instead of ink, and laid down as an electronic circuit on a polymer matrix 102. Beneficially, the inkjet printer is a low-cost technology for producing printed graphene that is post-printing processed with a laser to make functional materials therewith. Beneficially, use of laser induces hydrophobicity in the inkjet-printed graphene by aligning the graphene nanoplatelets 104 in a vertical orientation (as discussed above). Optionally, other post-printing processing may be performed on the printed graphene as discussed hereinabove.

In an example, under optimized conditions, using water-soluble single-layered graphene oxide (GO) and few-layered graphene oxide (EGO), various high image quality patterns may be printed on diverse flexible substrates, including paper, poly(ethylene terephthalate) (PET) and polyimide (PI), with a simple and low-cost inkjet printing technique. The graphene-based patterns printed on plastic substrates demonstrate a high electrical conductivity after thermal reduction, and more importantly, retention of the same conductivity over severe bending cycles. Accordingly, flexible electric circuits and a hydrogen peroxide chemical sensor may be fabricated demonstrating that graphene materials can be easily produced on a large scale and possess outstanding electronic properties. Moreover, simple inkjet printing techniques have great potential for the convenient fabrication of flexible and low-cost graphene-based electronic devices.

Alternatively, optionally, a Salt Impregnated Inkjet Maskless Lithography (SIIML) is used to print graphene. The SIIML uses an inkjet printer to create inexpensive graphene circuits with high electrical conductivity. Specifically, salt is added to the ink, which is later washed away to leave microsized divots or craters in the surface. In an example, the textured printed graphene surface is able to bind with pesticide-sensing enzymes to increase sensitivity during pesticide biosensing. The graphene pesticide test strip detects selected compounds through electrochemical sensing. These sensors can detect contaminants as small as 0.6 nanometers (nM) in length. Similar to pesticides, inkjet-printed graphene can be adapted for field use to detect a wide range of samples, including pathogens in food and fertilizer in soil and water. Beneficially, the inkjetprinting technology is so inexpensive, that the sensors could be used across an entire farm field to monitor pesticides and fertilizers so that farmers could limit their use and apply only what is truly needed. Moreover, the sensors, based on inject printed graphene, can be designed to detect pathogens in food processing facilities to prevent food contamination, monitor cattle diseases, for example, before physical symptoms are present, and for a variety of in-field sensing applications that require low-cost but highly sensitive biosensors.

Optionally, the layered polymer nanocomposite 100 is used in any of: semi-permanent coatings, anti-microbial coatings, anti-viral coatings, medical devices, anti-abrasive coatings, remolded products, surfaces, wherein the semi-permanent coating is removable. The layered polymer nanocomposite 100 is a tri-layer semi-permanent coating. The term "semi-permanent coating" refers to a non-permanent coating that is easy and fats to apply and easy to remove, such as by peeling off. Moreover, graphene is known to possess anti-microbial and anti-viral properties and therefore the layered polymer nanocomposite 100 coating is sensitive to microbes and viruses, such as COVID-19 or other viruses, and is suitable for detecting and analysing said microbes and viruses. Beneficially, the layered polymer nanocomposite 100 coatings are suitable for detecting contaminants of size in a range between 0.2-100 nanonnetre (nnn).

Moreover, the layered polymer nanocomposite 100 is an anti-biofouling material. Beneficially, the layered polymer nanocomposite 100 prevents growing of biological materials, such as microorganism, on the surfaces of devices (for example chemical or biological sensors) that would inhibit the optimal performance of such devices. Additionally or alternatively, the layered polymer nanocomposite 100 can also have applications in flexible electronics, washable sensors in textiles, microfluidic technologies, drag reduction, de-icing, electrochemical sensors and other technologies employing graphene nanoplatelets 104 and electrical stimulation. Beneficially, the self-cleaning wearable/washable electronics are resistant to stains, or ice and biofilm formation.

Furthermore, the structure of graphene and MoS2 enables the application of layered polymer nanocomposite 100 as anti-abrasive coatings for use in devices or surfaces subjected to extreme mechanical stress. Furthermore, the enhanced mechanical strength (toughness and flexibility) makes the use of the layered polymer nanocomposite 100 for manufacturing medical devices such as swabs, strips, and so on, food-grade remolded products, such as packaging material, wrapping sheets, and so on, as well as surfaces for use in public places. Beneficially, the graphene nanoplatelets are non-toxic and bacteriostatic, thus find application in the production of various medical devices to ensure better prevention properties for the spread of the infection from the microbe or the virus.

Optionally, the layered polymer nanocomposite 100 further comprises an assay substrate, wherein a change in the assay substrate is correlated with the presence of a microorganism. Notably, the M0S2 possesses electrochemical platform for detection and analysis of biological material, such as microorganisms, viruses, nucleic acids, proteins, antibiotics, neurotransmitters and the like, as well as hazardous chemicals (such as metal ions, pesticides or organophosphates). Organophosphates are certain classes of insecticides used on crops throughout the world to kill insects. Beneficially, the layered polymer nanocomposite 100 is configured to detect organophosphates at levels 40 times smaller than the U.S. Environmental Protection Agency (EPA) recommendations. Additionally, beneficially, quantifying insecticide runoff and drift enables characterizing its long-term effects and identifying ways to minimize said effects.

Besides, the assay substrate, such as a biolunninogenic substrate or a dye, may be incorporated in the layered polymer nanocomposite 100 to enable detection of the biological material. Moreover, suitable assay substrates may be incorporated for disease identification. Typically, the M0S2 and assay substrate provide a larger surface area and high conductivity for receiving electrons from a microbe or a virus, and thereby reporting by means of chemical (such as generation of reactive oxygen species (ROS)) or fluorescent (bioluminescent) signals the presence of infection on the surface coated with the layered polymer nanocomposite 100. In an example, when a suitable assay substrate combines with a molecule (such as ATP) secreted or given away by a microbe or a virus, the assay substrate and the molecule undergo a chemical reaction often catalysed by a catalyst (such as an enzyme) associated with the assay substrate to generate a chemical energy. The chemical energy excites specific molecules associated with the assay substrate or the microbe or a virus. The excitation of specific molecules is manifested as photon emission, light production or colour change and recorded by the sensor.

Optionally, the layered polymer nanocomposite 100 further comprises a plasticizer, a stabilizer, a filler, an impact modifier. Optionally, the plasticizer imparts flexibility, malleability, pliability, durability, and plasticity to the layered polymer nanocomposite 100. Suitable plasticizers include, but are not limited to, tributyl citrate, acetyl tributyl citrate, diethyl phthalate, glycerol triacetate, glycerol tripropionate, triethyl citrate, acetyl triethyl citrate, phosphate esters (for example, triphenyl phosphate), long-chain fatty acid esters, aromatic sulfonamides, hydrocarbon processing oil, propylene glycol, epoxyfunctionalized propylene glycol, polyethylene glycol, polypropylene glycol, epoxidized soybean oil, acetylated coconut oil, linseed oil, and epoxidized linseed oil. The filler alters any of: mechanical, physical and/or chemical properties of the layered polymer nanocomposite 100. Examples of filler include, but are not limited to, magnesium oxide, hydrous magnesium silicate, aluminium oxides, silicon oxides, titanium oxides, calcium carbonate, clay, chalk, boron nitride, limestone, diatomaceous earth, mica, glass quartz, ceramic and/or glass microbeads, metal or metal oxide fibres and particles, Magnetite®, Magnetic Iron(III) oxide, carbon nanotubes and fibres. The stabilizer may be a thermal stabilizer that improves resistance to heat, an oxidative stabilizer that improves resistance to oxidative damages due to oxidation by atmospheric air, corrosive or other reactive chemicals, or a light stabilizer that improves resistance to damage from exposure to natural or artificial light. Examples of the stabilizer include, but are not limited to, hydrogen chloride scavenger (such as epoxidized soybean oil), alkoxy substituted hindered amine light stabilizers (HALS) (for example, N-O-R HALS), N-(1,3-dimethylbuty1)-1W-phenyl-p-phenylenediamine (6PPP), Nisopropyl-N-phenyl-phenylenediamine (IPPD), 6-ethoxy-2,2,4-trimethyl1, 2-dihydroquinoline (ETMQ), ethylene diurea (EDU), paraffin wax, ultraviolet (UV) light stabilizers and hindered amine light stabilizers (HALS or HAS). The impact modifier increases resistance of the layered polymer nanoconnposite 100 against breaking, under impact conditions. Examples of impact modifier include, but are not limited to, olefinic polymers or copolymers (for example, ethylene, propylene, or a combination thereof with various (meth)acrylate monomers and/or various maleic-based monomers), alkyl(methyl)acrylates (for example, butyl acrylate, hexyl acrylate, propyl acrylate, or a combination thereof), alkyl(meth)acrylate monomer with acrylic acid (for example, maleic anhydride, glycidyl methacrylate, or a combination thereof), monomers providing additional moieties (for example, carboxylic acid, anhydride, epoxy), block copolymers (for example, A-B diblock copolymers, A-B-A triblock copolymers, and rubber block, B, derived from isoprene, butadiene or isoprene and butadiene).

Moreover, in an embodiment, the disclosed layered polymer nanocomposite comprises nano-electronics embedded into a flexible coating, for example sensors for detecting bacterial and/or viral strains or detecting a chemical, electrical, mechanical, or photoelectric change.

In an example implementation, the layered polymer nanoconnposite may find application in electronic devices, such as organic light emitting diodes (OLED), liquid crystal display (LCD), color-changing clothes, and so on. Typically, OLEDs (traditional OLEDs, light emitting polymers (LEPs) or polymer LEDs (PLEDs)) work in a similar way to conventional diodes and LEDs, but instead of using layers of n-type and p-type semiconductors, they use organic molecules to produce their electrons and holes. A simple OLED is made up of six different layers. On the top and bottom there are layers of protective glass or plastic referred to as the seal layer and the substrate layer, respectively. In between the seal and substrate layers, OLED comprises a negative terminal (namely, cathode) and a positive terminal (namely, anode). Moreover, in between the anode and the cathode, are two layers made from organic molecules called the emissive layer (where the light is produced, which is next to the cathode) and the conductive layer (next to the anode). Upon applying a potential difference (i.e. voltage) across the anode and the cathode, electricity starts to flow therebetween when the anode loses electrons (or gains holes) and the cathode receives electrons from the power source. As a result, the emissive layer becomes negatively charged and the conductive layer becomes positively charged, and release bursts of energy in the form of particles of light (namely, photons) upon recombination of the electrons and the holes. It will be appreciated that the process of recombination occurs many times a second, therefore, OLED produces continuous light for as long as the current keeps flowing. Moreover, OLED may be configured to produce colored light by adding a colored filter just beneath the seal or substrate layers. Notably, arranging thousands of red, green, and blue OLEDs next to one another (or on top of one another) and switching them on and off independently, produces complex, hi-resolution colored pictures similar to the pixels in a conventional LCD screen. In OLEDs, layers of polymer turn electricity into light and vice versa.

Furthermore, the teachings of the present disclosure may be implemented in fabrication of graphene-based devices, such as OLEDs, LEDs, touchscreens and solar cells, as an alternative to the conventional indium tin oxide (ITO) devices. It will be appreciated that the demand for alternative transparent conductors (TCs) to fabricate next-generation devices is increasing due to the ever-increasing price and limited geographical availability of indium as well as the market trend towards flexible devices. Graphene exhibits high optical transparency and electronic mobility, making it a potential material for opto-electronic applications such as touch screens, LEDs, and solar cells. Additionally, graphene-based devices deliver superior performance compared to advanced indium tin oxide (ITO) devices. Moreover, graphene is flexible, clear, exceptional conductor of both heat and electrical current, and extremely robust, and therefore a potential application of the layered polymer nanocomposite based on graphene is in producing OLED electrodes from graphene. Optionally, the electrodes attached to the OLEDs have an area of around 2 cm by 1 cm (1/2 inch by 1/4 inch), and are created using a process of chemical vapor deposition (CVD), where methane and hydrogen are pumped into a vacuum chamber where a copper plate has been heated to 800° C (1,472° F). A chemical reaction occurs between the two gases and, as the methane dissolves into the copper, it forms graphene atoms on the surface. Once the layer is sufficiently formed, the whole set up is allowed to cool, a protective polymer sheet is applied, and the copper is then chemically etched away to reveal a single-atom layer of pure graphene. It will be appreciated that though this is not the first flexible display to use graphene in its construction, it is the first to incorporate OLED technology, which is a large step toward full-color screens and fast response times.

Beneficially, electrons pass through graphene with almost no resistance and generate very little heat. Graphene itself is a good thermal conductor that dissipates heat quickly. Due to their superior performance, electronics made from graphene run much faster. Therefore, the graphene-based FET work better than silicon transistors that are used in today's computers, especially in terms of microprocessors that, built using silicon transistors, have processing speeds mostly in a range of 3 to 4 gigahertz, thereby limiting the rate of signals and power transfers, mostly due to silicon's resistance. In this regard, a logic gate series provides that the graphene-based FET uses less power but could work 1,000 times faster than ones with silicon.

With graphene used in everything from conductors, through to supercapacitors, solar cells and a raft of other electronic devices, displays made from this material are a logical choice for improving the longevity, robustness, and usability of photovoltaic cells, wearable, flexible textiles and medical devices. This research may lead to developments in these areas in the very near future. Moreover, graphene has higher charge carrier mobility, but typically lower carrier concentrations. Therefore, the overall performance of graphene as an electrode needs to be improved, such as by doping, to increase the number of available charge carriers. However, care must be taken to avoid damaging the high optical transparency of graphene during the doping process, as this is an important quality for a transparent electrode. Furthermore, efficient exchange of charge carriers between the active layer and the electrode is equally important in order to perform the desired opto-electronic function. The electronic bands of the active materials and the electrode bend and modulate with one another, thereby fine-tuning the optoelectronic performance of the final device. Hence, it is essential to investigate the charge carriers exchanged between the active layer and the electrode.

Referring to FIG. 2, shown is a flow chart 200 of steps of a method of manufacturing a layered polymer nanoconnposite, according to an embodiment of the present disclosure. The layered polymer nanocomposite comprises a polymer matrix; graphene nanoplatelets dispersed in the polymer matrix, wherein the graphene nanoplatelets are stabilized with the polymer matrix; and a third-party material having nonzero band gap value. The method comprises, at step 202, dispersing the graphene nanoplatelets in the polymer matrix to form a substrate layer having a first side and a second side; at step 204, transferring a third-party material on the first side of the substrate layer to form a circuit-primed substrate layer having an open side; and at step 206, adding a seal layer on the open side of the circuit-primed substrate layer to form the layered polymer nanoconnposite.

The steps 202, 204 and 206 are only illustrative and other alternatives can also be provided where one or more steps are added, one or more steps are removed, or one or more steps are provided in a different sequence without departing from the scope of the claims herein.

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.

Claims (6)

1. CLAIMS1. A layered polymer nanocomposite (100) comprising: a polymer matrix (102); graphene nanoplatelets (104) dispersed in the polymer matrix (102), wherein the graphene nanoplatelets are stabilized with the polymer matrix; and a third-party material (106) having a non-zero band gap value.
2. 2. A layered polymer nanocomposite (100) of claim 1, wherein the polymer matrix (102) comprises vinylic, styrenic or acrylic polymer, and wherein the vinylic polymer is a polyvinyl butyral.
3. 3. A layered polymer nanocomposite (100) of any of claim 1, wherein the third-party material (106) is selected from a group comprising: molybdenum disulfide, carbon (diamond), silicon, silicon dioxide, silicon nitride, silicon carbide, gallium nitride, gallium phosphide, gallium arsenide, lead sulfide, copper oxide, magnesium oxide, zinc oxide, titanium oxide, aluminium nitride, aluminium gallium nitride, aluminium gallium oxide, cubic-boron nitride, germanium, piezoelectric ink.
4. 4. A layered polymer nanocomposite (100) of any of the preceding claims, wherein the layered polymer nanocomposite is used in any of: semi-permanent coatings, anti-microbial coatings, anti-viral coatings, medical devices, anti-abrasive coatings, remolded products, surfaces, wherein the semi-permanent coating is removable.
5. 5. A layered polymer nanocomposite (100) of any of the preceding claims, wherein the layered polymer nanocomposite further comprises an assay substrate, wherein a change in the assay substrate is correlated with the presence of a microorganism.
6. 6. A method of manufacturing a layered polymer nanocomposite, the layered polymer nanocomposite (100) comprising: - a polymer matrix (102); - graphene nanoplatelets (104) dispersed in the polymer matrix (102), wherein the graphene nanoplatelets are stabilized with the polymer matrix; and - a third party material (106) having non-zero band gap value, wherein the method comprises: a) dispersing the graphene nanoplatelets in the polymer matrix to form a substrate layer having a first side and a second side; b) transferring a third-party material on the first side of the substrate layer to form a circuit-primed substrate layer having an open side; and c) adding a seal layer on the open side of the circuit-primed substrate layer to form the layered polymer nanocomposite.