Increasing customer demand for durable and functional apparel manufactured in a sustainable manner has created an opportunity for nanomaterials to be integrated into textile substrates. Nanomoieties can induce stain repellence, wrinkle-freeness, static elimination, and electrical conductivity to fibers without compromising their comfort and flexibility. Nanomaterials also offer a wider application potential to create connected garments that can sense and respond to external stimuli via electrical, color, or physiological signals. This review discusses electronic and photonic nanotechnologies that are integrated with textiles and shows their applications in displays, sensing, and drug release within the context of performance, durability, and connectivity. Risk factors including nanotoxicity, nanomaterial release during washing, and environmental impact of nanotextiles based on life cycle assessments have been evaluated. This review also provides an analysis of nanotechnology consolidation in the textiles market to evaluate global trends and patent coverage, supplemented by case studies of commercial products. Perceived limitations of nanotechnology in the textile industry and future directions are identified.

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The conformal deposition of metal nanoparticles (Au, Pd, and Pt) onto natural cellulose fibers using two chemical strategies is reported. The driven mechanism responsible for the high surface coverage of the substrates was identified as the electrostatic interactions between the positively charged cellulose and the either negatively charged nanoparticles or negative metal complex ions. The natural cellulose fibers were rendered cationic by grafting ammonium ions, using an epoxy substitution reaction, to the abundant hydroxyl groups present in cellulose molecules. The first method involved the electrostatic assembly of citrate-stabilized metal nanoparticles directly onto the cationic surfaces of cellulose. The second method involved the adsorption of negative metal complex ions onto the cationic cellulose followed by a reduction reaction. The attained metal nanoparticles bound with cellulose fibers were characterized by electron microscopy (TEM and SEM) and energy-dispersive X-ray spectroscopy (EDX). Both pathways generated metal nanoparticles with high packing densities on the cellulose substrates even when very dilute solutions of metal colloids or metal salts were used. Achieving high surface coverage with low-concentration precursor solutions may open an avenue for the production of flexible catalytic mantles or highly functionalized textile substrates.

Assembly of metal nanoparticles (Ag, Au, Pt) onto nylon 6 nanofibers by controlling the interfacial hydrogen-bonding interactions has been demonstrated. Metal nanoparticles were synthesized in aqueous media using sodium citrate as a stabilizer. Nylon 6 nanofiber mats, produced by electrospinning, were immersed into pH-adjusted solutions of metal nanoparticles. The key factor determining the assembly phenomena was identified as the hydrogen-bonding interactions between the amide groups in the nylon 6 backbone and the carboxylic acid groups capped on the surface of the metal nanoparticles. The assembly was strongly dependent on the pH of the media, which affected the protonation of the carboxylate ions on the metal nanoparticles, hence influencing the hydrogen-bonding interactions between nanofibers and nanoparticles. High surface coverage of the nanofibers by the Ag nanoparticles was found at pH intervals from 3 to 6, whereas only a few Ag nanoparticles were found on the surface of the fibers when the pH was greater than 7. The nylon 6 nanofiber mats decorated with Ag nanoparticles exhibited strong antibacterial activity against Escherichia coli.

Atomic-scale material deposition is utilized to achieve uniform coverage and modification of the surface properties of natural fiber and woven fabric materials, where irregular nanoscale features are embedded in a macroscale interpenetrating fiber network. The complex surface topology of the woven fabric results in significantly different film-growth thickness per ALD cycle as compared to planar surfaces coated using the same process conditions, likely due to reactant adsorption within the fiber starting material, as well as impeded reactant transport out of the fabric system during the purge cycle. Cotton textiles modified with conformal nanoscale Al2O3 are found to show extreme hydrophobic effects, distinctly different from planar surfaces that receive the same coatings. The results highlight key concerns for achieving controlled conformal coatings on complex surfaces and open the possibility for new textile finishing approaches to create novel fabric-based materials with specialized function and performance.

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Cellulose nanoparticles obtained by acid hydrolysis of cellulose paper were used to reinforce polystyrene composite films. The nonionic surfactant sorbitan monostearate was utilized to improve the dispersion properties of the hydrophilic cellulose in hydrophobic matrix and to prevent the formation of aggregates. Turbidity tests were used to measure dispersion stability of the cellulose crystallites in the hydrophobic solvent used in the composite manufacture. A correlation was found between the dispersion stability in solvent and the formation of aggregates in the polymeric composites. Nanocomposite films were processed using a casting/evaporation technique. Thermal and mechanical properties of processed composites were studied by differential scanning calorimetry (DSC) and dynamical mechanical analyses (DMA), respectively. The results showed that the optimum addition of surfactant produced better dispersion of the cellulose particles in the polystyrene matrix and improved the mechanical properties of the resulting composite due to an enhanced compatibility. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers

Cotton fabric is covalently functionalized with a porous β-cyclodextrin polymer by including the fabric in the polymerization mixture. The resulting functionalized fabric (CD-TFP@cotton) sequesters organic micropollutants, such as bisphenol A, from water with outstanding speed and a capacity 10-fold higher than that of untreated cotton. The functionalized fabric also readily captures volatile organic compounds (VOCs) from the vapor phase more quickly and with a capacity higher than that of untreated cotton as well as three commercially available fabric-based adsorbents. Volatile adsorbed pollutants were fully extracted from CD-TFP@cotton under reduced pressure at room temperature, permitting simple reuse. These properties make cotton functionalized with the cyclodextrin polymer of interest for water purification membranes, odor controlling fabrics, and respirators that control exposure to VOCs. This functionalization approach is scalable, likely to be amenable to other fibrous substrates, and compatible with existing fiber manufacturing techniques.