Nanofabrics

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Nanofabrics are textiles engineered with small particles that give ordinary materials advantageous properties such as superhydrophobicity (extreme water resistance, also see "Lotus effect"), [1] odor and moisture elimination, [2] increased elasticity and strength, [3] and bacterial resistance. [4] Depending on the desired property, a nanofabric is either constructed from nanoscopic fibers called nanofibers, or is formed by applying a solution containing nanoparticles to a regular fabric. Nanofabrics research is an interdisciplinary effort involving bioengineering, [5] molecular chemistry, physics, electrical engineering, computer science, and systems engineering. [3] Applications of nanofabrics have the potential to revolutionize textile manufacturing [6] and areas of medicine such as drug delivery and tissue engineering. [7]

Contents

Electron microscope image of cotton fibers coated with gold (left) and palladium (right) nanoparticles. The nanoparticles make up just the outline of the fibers in these two images. Cotton fibers coated with nanoparticles, from Cornell University's Textiles Nanotechnology Laboratory.jpeg
Electron microscope image of cotton fibers coated with gold (left) and palladium (right) nanoparticles. The nanoparticles make up just the outline of the fibers in these two images.

Nanoscale

A fiber that has a width of less than 1000 nanometers (1000 nm or 1 μm) is generally defined as a nanofiber. [9] A nanoparticle is defined as a small group of atoms or molecules with a radius of less than 100 nanometers (100 nm). [10] Particles on the nanoscale have a very high surface area to volume ratio, whereas this ratio is much lower for objects on the macroscopic scale. A high relative surface area means that a large proportion of a particle's mass exists on its surface, so nanofibers and nanoparticles show a greater level of interaction with other materials. The high surface area to volume ratio observed in very small particles is what makes it possible to create many special properties exhibited by nanofabrics. [11]

Manufacture

The use of nanoparticles and nanofibers to produce specialized nanofabrics became a subject of interest after the sol-gel [12] and electrospinning [13] techniques were fully developed in the 1980s. [14] Since 2000, dramatic increases in global funding have accelerated research efforts in nanotechnology, including nanofabrics research. [15]

Sol-gel

The sol-gel process is used to create gel-like solutions which can be applied to textiles as a liquid finish to create nanofabrics with novel properties. [16] The process begins with dissolving nanoparticles in a liquid solvent (often an alcohol). Once dissolved, several chemical reactions take place that cause the nanoparticles to grow and establish a network throughout the liquid. [17] The network transforms the solution into a colloid (a suspension of solid particles in a liquid) with a gelatinous texture. Finally, the colloid must go through a drying process to remove excess solvent from the mixture before it can be used to treat fabrics. [18] The sol-gel process is used in a similar fashion to make polymer nanofibers, which are long, ultra-thin chains of proteins bonded together.

Electrospinning

Electrospinning extracts nanofibers from polymer solutions (synthesized by the sol-gel process) and collects them to form nonwoven nanofabrics. [19] A strong electric field is applied to the solution to charge the polymer strands. The solution is put into a syringe and aimed at an oppositely charged collector plate. When the force of attraction between the polymer nanofibers and the collector plate exceed the surface tension of the solution, the nanofibers are released from the solution and deposit onto the collector plate. The deposited fibers form a porous nanofabric that can aid in drug delivery and tissue engineering depending on the type of polymer used. [20]

Applications

Textile Manufacturing

When nanoengineered coatings are applied to fabrics, the nanoparticles readily form bonds with the fibers of the material. The high surface area relative to the volume of particles increases their chemical reactivity, allowing them to stick to materials more permanently. Fabrics treated with nanoparticle coatings during manufacturing produce materials that kill bacteria, eliminate moisture and odor, and prevent static electricity. Polymer nanofiber coatings applied to textiles bond to the material at one end of the polymer, forming a surface of tiny, hair-like structures. [16] The polymer "hairs" create a thin layer that prevents liquids from making contact with the actual fabric. Nanofabrics with dirt-proof, stain-proof, and superhydrophobic properties are possible as a result of the layer formed by polymer nanofibers. [6]

Development of nanofabrics for use in the clothing and textiles industry is still in its early stages. Some applications such as bacteria-resistant clothing are not yet practical from an economic standpoint. For example, a Cornell University student's prototype for a bactericidal jacket cost $10,000 alone, [4] so it may be a long time before nanofabric clothing is on the market.

Drug Delivery

Nanofabrics used in medicine can deliver antibiotics, anticancer drugs, proteins, and DNA in precise quantities. Electrospinning creates porous nanofabrics that can be loaded with the desired drug which are then applied to the tissue of the targeted area. The drug passes through the tissue by diffusion, a process in which substances move through a membrane from high to low concentration. The rate at which the drug is administered can be changed by altering the composition of the nanofabric. [21]

Tissue Engineering

Nonwoven fabrics made by electrospinning have the potential to assist in the growth of organ tissue, bone, neurons, tendons, and ligaments. Polymer nanofabrics can act either as a scaffold to support damaged tissue or as a synthetic substitute for actual tissue. Depending on the function, the nanofabric can be made of natural or synthetic polymers, or a combination of both. [20]

Environmental Implications

As nanotechnology advances, many studies have been conducted to determine the effects nanoengineered materials can have on the environment. [22] Most textiles can lose up to 20% of their mass during their lifetime, so nanoparticles used in production of nanofabrics are at risk of being released into the air and waterways. [23]

Nano-silver is expected to have as much as 49.5% of its global production taken by the nanotextiles industry due to its antibacterial properties. It is predicted that 20% of the nano-silver used in the nanofabrics industry will be released into waterways which could cause harm to microorganisms. However, more than 90% of nano-silver is removed during treatment at wastewater facilities, so it is likely that the environmental impact will be minimal. [24] A study on aluminum oxide nanoparticles showed that inhalation caused inflammation in rat lungs. [25] Aluminum oxide nanoparticles are not used in large quantity, so its health risks are negligible. Other studies conducted for nanoparticles suggest that their environmental impact should be low as the nanotextiles industry continues to grow.

Related Research Articles

<span class="mw-page-title-main">Nanoparticle</span> Particle with size less than 100 nm

A nanoparticle or ultrafine particle is usually defined as a particle of matter that is between 1 and 100 nanometres (nm) in diameter. The term is sometimes used for larger particles, up to 500 nm, or fibers and tubes that are less than 100 nm in only two directions. At the lowest range, metal particles smaller than 1 nm are usually called atom clusters instead.

<span class="mw-page-title-main">Electrospinning</span>

Electrospinning is a fiber production method that uses electric force to draw charged threads of polymer solutions or polymer melts up to fiber diameters in the order of some hundred nanometers. Electrospinning shares characteristics of both electrospraying and conventional solution dry spinning of fibers. The process does not require the use of coagulation chemistry or high temperatures to produce solid threads from solution. This makes the process particularly suited to the production of fibers using large and complex molecules. Electrospinning from molten precursors is also practiced; this method ensures that no solvent can be carried over into the final product.

In materials science, the sol–gel process is a method for producing solid materials from small molecules. The method is used for the fabrication of metal oxides, especially the oxides of silicon (Si) and titanium (Ti). The process involves conversion of monomers into a colloidal solution (sol) that acts as the precursor for an integrated network of either discrete particles or network polymers. Typical precursors are metal alkoxides. Sol-gel process is used to produce ceramic nanoparticles.

<span class="mw-page-title-main">Carbon nanofiber</span>

Carbon nanofibers (CNFs), vapor grown carbon fibers (VGCFs), or vapor grown carbon nanofibers (VGCNFs) are cylindrical nanostructures with graphene layers arranged as stacked cones, cups or plates. Carbon nanofibers with graphene layers wrapped into perfect cylinders are called carbon nanotubes.

<span class="mw-page-title-main">Nanofiber</span>

Nanofibers are fibers with diameters in the nanometer range. Nanofibers can be generated from different polymers and hence have different physical properties and application potentials. Examples of natural polymers include collagen, cellulose, silk fibroin, keratin, gelatin and polysaccharides such as chitosan and alginate. Examples of synthetic polymers include poly(lactic acid) (PLA), polycaprolactone (PCL), polyurethane (PU), poly(lactic-co-glycolic acid) (PLGA), poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV), and poly(ethylene-co-vinylacetate) (PEVA). Polymer chains are connected via covalent bonds. The diameters of nanofibers depend on the type of polymer used and the method of production. All polymer nanofibers are unique for their large surface area-to-volume ratio, high porosity, appreciable mechanical strength, and flexibility in functionalization compared to their microfiber counterparts.

<span class="mw-page-title-main">Dip-coating</span> Industrial coating process

Dip coating is an industrial coating process which is used, for example, to manufacture bulk products such as coated fabrics and condoms and specialised coatings for example in the biomedical field. Dip coating is also commonly used in academic research, where many chemical and nano material engineering research projects use the dip coating technique to create thin-film coatings.

<span class="mw-page-title-main">Nanochemistry</span> Combination of chemistry and nanoscience

Nanochemistry is an emerging sub-discipline of the chemical and material sciences that deals with the development of new methods for creating nanoscale materials. The term "nanochemistry" was first used by Ozin in 1992 as 'the uses of chemical synthesis to reproducibly afford nanomaterials from the atom "up", contrary to the nanoengineering and nanophysics approach that operates from the bulk "down"'. Nanochemistry focuses on solid-state chemistry that emphasizes synthesis of building blocks that are dependent on size, surface, shape, and defect properties, rather than the actual production of matter. Atomic and molecular properties mainly deal with the degrees of freedom of atoms in the periodic table. However, nanochemistry introduced other degrees of freedom that controls material's behaviors by transformation into solutions. Nanoscale objects exhibit novel material properties, largely as a consequence of their finite small size. Several chemical modifications on nanometer-scaled structures approve size dependent effects.

Nanomanufacturing is both the production of nanoscaled materials, which can be powders or fluids, and the manufacturing of parts "bottom up" from nanoscaled materials or "top down" in smallest steps for high precision, used in several technologies such as laser ablation, etching and others. Nanomanufacturing differs from molecular manufacturing, which is the manufacture of complex, nanoscale structures by means of nonbiological mechanosynthesis.

Nanotechnology is impacting the field of consumer goods, several products that incorporate nanomaterials are already in a variety of items; many of which people do not even realize contain nanoparticles, products with novel functions ranging from easy-to-clean to scratch-resistant. Examples of that car bumpers are made lighter, clothing is more stain repellant, sunscreen is more radiation resistant, synthetic bones are stronger, cell phone screens are lighter weight, glass packaging for drinks leads to a longer shelf-life, and balls for various sports are made more durable. Using nanotech, in the mid-term modern textiles will become "smart", through embedded "wearable electronics", such novel products have also a promising potential especially in the field of cosmetics, and has numerous potential applications in heavy industry. Nanotechnology is predicted to be a main driver of technology and business in this century and holds the promise of higher performance materials, intelligent systems and new production methods with significant impact for all aspects of society.

Polymer nanocomposites (PNC) consist of a polymer or copolymer having nanoparticles or nanofillers dispersed in the polymer matrix. These may be of different shape, but at least one dimension must be in the range of 1–50 nm. These PNC's belong to the category of multi-phase systems that consume nearly 95% of plastics production. These systems require controlled mixing/compounding, stabilization of the achieved dispersion, orientation of the dispersed phase, and the compounding strategies for all MPS, including PNC, are similar. Alternatively, polymer can be infiltrated into 1D, 2D, 3D preform creating high content polymer nanocomposites.

<span class="mw-page-title-main">Janus particles</span> Type of nanoparticle or microparticle

Janus particles are special types of nanoparticles or microparticles whose surfaces have two or more distinct physical properties. This unique surface of Janus particles allows two different types of chemistry to occur on the same particle. The simplest case of a Janus particle is achieved by dividing the particle into two distinct parts, each of them either made of a different material, or bearing different functional groups. For example, a Janus particle may have one-half of its surface composed of hydrophilic groups and the other half hydrophobic groups, the particles might have two surfaces of different color, fluorescence, or magnetic properties. This gives these particles unique properties related to their asymmetric structure and/or functionalization.

Green nanotechnology refers to the use of nanotechnology to enhance the environmental sustainability of processes producing negative externalities. It also refers to the use of the products of nanotechnology to enhance sustainability. It includes making green nano-products and using nano-products in support of sustainability.

Spinning is a manufacturing process for creating polymer fibers. It is a specialized form of extrusion that uses a spinneret to form multiple continuous filaments.

Nano-scaffolding or nanoscaffolding is a medical process used to regrow tissue and bone, including limbs and organs. The nano-scaffold is a three-dimensional structure composed of polymer fibers very small that are scaled from a Nanometer scale. Developed by the American military, the medical technology uses a microscopic apparatus made of fine polymer fibers called a scaffold. Damaged cells grip to the scaffold and begin to rebuild missing bone and tissue through tiny holes in the scaffold. As tissue grows, the scaffold is absorbed into the body and disappears completely.

<span class="mw-page-title-main">Melt electrospinning</span>

Melt electrospinning is a processing technique to produce fibrous structures from polymer melts for applications that include tissue engineering, textiles and filtration. In general, electrospinning can be performed using either polymer melts or polymer solutions. However, melt electrospinning is distinct in that the collection of the fiber can very focused; combined with moving collectors, melt electrospinning writing is a way to perform 3D printing. Since volatile solvents are not used, there are benefits for some applications where solvent toxicity and accumulation during manufacturing are a concern.

Green textiles are fabrics or fibres produced to replace environmentally harmful textiles and minimise the ecological impact. Green textiles are part of the sustainable fashion and eco-friendly trends, providing alternatives to the otherwise pollution-heavy products of conventional textile industry, which is deemed the most ecologically damaging industry.

<span class="mw-page-title-main">Melt blowing</span> Micro- and nanofiber fabrication method

Melt blowing is a conventional fabrication method of micro- and nanofibers where a polymer melt is extruded through small nozzles surrounded by high speed blowing gas. The randomly deposited fibers form a nonwoven sheet product applicable for filtration, sorbents, apparels and drug delivery systems. The substantial benefits of melt blowing are simplicity, high specific productivity and solvent-free operation. Choosing an appropriate combination of polymers with optimized rheological and surface properties, scientists have been able to produce melt-blown fibers with an average diameter as small as 36 nm.

<span class="mw-page-title-main">Aluminium oxide nanoparticle</span>

Nanosized aluminium oxide occurs in the form of spherical or nearly spherical nanoparticles, and in the form of oriented or undirected fibers.

<span class="mw-page-title-main">Coated fabrics</span> Fabrics that go through a process of coating

Coated fabrics are those that have undergone a coating procedure to become more functional and hold the added properties, such as cotton fabrics becoming impermeable or waterproof. Coated textiles are used in a variety of applications, including blackout curtains and the development of waterproof fabrics for raincoats.

<span class="mw-page-title-main">Medical textiles</span> Textiles for medical and healthcare use

Medical textiles are various fiber-based materials intended for medical purposes. Medical textile is a sector of technical textiles that focuses on fiber-based products used in health care applications such as prevention, care, and hygiene. The spectrum of applications of medical textiles ranges from simple cotton bandages to advanced tissue engineering. Common examples of products made from medical textiles include dressings, implants, surgical sutures, certain medical devices, healthcare textiles, diapers, menstrual pads, wipes, and barrier fabrics.

References

  1. ↑ Evans, Jon. "Nanotech clothing fabric 'never gets wet'". New Scientist.
  2. ↑ "Small Particles Show Big Promise in Beating Unpleasant Odors". American Chemical Society.
  3. 1 2 "Application of Nanotechnology in Textile". Jayaram & Co.
  4. 1 2 Stover, Dawn. "Potent new 'nanofabrics' repel germs". CNN. Retrieved 25 October 2012.
  5. ↑ "Bioengineers at Harvard's Wyss Institute Successfully Replicate Nature's Design Principles to Create Customized Nanofabrics". Wyss Institute.
  6. 1 2 Eufinger, Karin; Isbel De Schrijver (2009-09-23). "Incorporation of Nanotechnology in Textile Applications". Azonano.
  7. ↑ Shi, Jinjun; Votruba, Alexander R; Farokhzad, Omid C; Langer, Robert (August 2010). "Nanotechnology in Drug Delivery and Tissue Engineering: From Discovery to Applications". Nano Letters. 10 (9): 3223–3230. doi:10.1021/nl102184c. PMC   2935937 . PMID   20726522.
  8. ↑ Juan, Hinestroza. "Textiles Nanotechnology Laboratory". Hinestroza Research Group. Textiles Nanotechnology Laboratory at Cornell University.
  9. ↑ "What are Nanofibers?". SNS Nanofiber Technology LLC. Archived from the original on 2013-02-02.
  10. ↑ Charles P. Poole Jr.; Frank J. Owens (2003). Introduction to Nanotechnology. Hoboken, New Jersey: John Wiley & Sons, Inc. ISBN   9780471079354.
  11. ↑ Harkirat (June 2010). "Preparation and Characterization of Nanofluids and Some Investigation In Biological Applications".
  12. ↑ Brinker, C.J.; G.W. Scherer (1990). The Physics and Chemistry of Sol-Gel Processing. Academic Press. ISBN   978-0-12-134970-7.
  13. ↑ Doshi, J.; D.H. Reneker (1995). "Electrospinning Process and Applications of Electrospun Fibers". Journal of Electrostatics. 35 (2–3): 151–160. doi:10.1016/0304-3886(95)00041-8.
  14. ↑ Klein, L.C.; G.J. Garvey (1980). "Kinetics of the Sol-Gel Transition". Journal of Non-Crystalline Solids. 38: 45–50. doi:10.1016/0022-3093(80)90392-0.
  15. ↑ "Global Funding of Nanotechnologies & Its Impact" (PDF). Cientifica. July 2011.
  16. 1 2 Sniderman, Debbie. "Using Liquid Finishes to Create Nanofabrics". ASME.
  17. ↑ Phalippou, Jean (May 2000). "Sol-gel: A Low Temperature Process for the Materials of the New Millennium".
  18. ↑ Wright, J.D.; N.A.J.M. Sommerdijk. Sol-Gel Materials: Chemistry and Applications.
  19. ↑ "Electrospinning Creates Ultra-fine Fibres for Many Applications". CSIRO. January 2009. Archived from the original on 2012-10-21.
  20. 1 2 Sill, Travis J.; Horst A. von Recum (2008). "Electrospinning: Applications in Drug Delivery and Tissue Engineering". Biomaterials. 29 (13): 1989–2006. doi:10.1016/j.biomaterials.2008.01.011. PMID   18281090.
  21. ↑ Seema Agarwal; Joachim H. Wendorff; Andreas Greiner (December 2008). "Use of Electrospinning Technique for Biomedical Applications". Polymer. 49 (26): 5603–5621. doi: 10.1016/j.polymer.2008.09.014 .
  22. ↑ Claudia Som; Peter Wick; Harald Krug; Bernd Nowack (2011). "Environmental and health effects of nanomaterials in nanotextiles and façade coatings". Environment International. 37 (6): 1131–1142. doi:10.1016/j.envint.2011.02.013. PMID   21397331.
  23. ↑ "Nanotechnology Textiles". December 2010.
  24. ↑ K. Tiede; A.B.A. Boxall; X.M. Wang; D. Gore; D. Tiede; M. Baxter; et al. (2010). Application of hydrodynamic chromatography–ICP-MS to investigate the fate of silver nanoparticles in activated sludge.
  25. ↑ S. Lu; R. Duffin; C. Poland; P. Daly; F. Murphy; E. Drost; et al. (2009). "Efficacy of simple short-term in vitro assays for predicting the potential of metal oxide nanoparticles to cause pulmonary inflammation". Environmental Health Perspectives. 117 (2): 241–7. doi:10.1289/ehp.11811. PMC   2649226 . PMID   19270794.
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