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We report the extraction of keratin nanofibers from the medulla of a parent yarn after denaturing the cuticle and cortex microstructures of a merino wool yarn. Controlled alkaline hydrolysis, followed by high-speed blending in acetic acid, allowed for the extraction of keratin protein nanofibers with an average diameter of 25 nm and a length of less than 3 μm. SEM and AFM analyses showed the removal of cuticle cells from the yarn. FT-IR and DSC analyses confirmed the hydrolysis and denaturation of the sheet protein matrix of cuticle cells. XPS analysis provided strong evidence for the gradual removal of the epicuticle, cuticle cells, and cortex of the hierarchical wool structure with an increase in alkaline hydrolysis conditions. It was confirmed that the merino wool yarn subjected to hydrolysis under alkaline conditions exposed its internal fibrillar surface. In an acetic acid medium, these fibrillar surfaces obtained a surface charge, which further supported the defibrillation of the structure into its individual nanofibrils during high-speed blending. The extracted nanostructures constitute mainly α-helical proteins. The morphology of the nanofibers is composed of a uniform circular cross-section based on the images obtained using AFM, TEM, and SEM. The extracted nanofibers were successfully fabricated into transparent sheets that can be used in several applications., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

A new approach was used to produce electrically conductive polyamide yarns, employing an electroless plating technique, which involved stabilizing silver nanoparticles on the surface of the yarn using Sn 2+ . First, the [Ag(NH 3 ) 2 ] + complex was reduced using Sn 2+ to produce silver nanoparticle seed layers on the fiber surface, followed by a formaldehyde reduction. The nucleation and growth of silver nanoparticles on the fiber surface were observed through SEM images, demonstrating varying degrees of silver deposition depending on the silver concentration. This deposition variation was confirmed through XRD patterns, TGA data and UV-vis spectra. Additionally, XPS characterization showed the evolution of the chemical state of silver and tin during the silver reduction process. Electrical resistance revealed that the resistance per unit length of the yarn ranged from 3 ± 0.3 Ω cm -1 to 70 ± 6 Ω cm -1 , depending on the silver concentration. The resulting silver-plated yarn was incorporated into a stretchable device, demonstrating stable resistance over multiple cycles. This method of fabricating conductive yarn has the potential to open up new possibilities in the design and manufacture of stretchable conductive devices for flexible electronics., Competing Interests: The authors declare no conflict of interest., (This journal is © The Royal Society of Chemistry.)

Propensity of a textile material to evaporate moisture from its surface, commonly referred to as the 'moisture management' ability, is an important characteristic that dictates the applicability of a given textile material in the activewear garment industry. Here, an infrared absorbing nanoparticle impregnated self-heating (IRANISH) fabric is developed by impregnating tin-doped indium oxide (ITO) nanoparticles into a polyester fabric through a facile high-pressure dyeing approach. It is observed that under simulated solar radiation, the impregnated ITO nanoparticles can absorb IR radiation, which is effectively transferred as thermal energy to any moisture present on the fabric. This transfer of thermal energy facilitates the enhanced evaporation of moisture from the IRANISH fabric surface and as per experimental findings, a 54 ± 9% increase in the intrinsic drying rate is observed for IRANISH fabrics compared with control polyester fabrics that are treated under identical conditions, but in the absence of nanoparticles. Approach developed here for improved moisture management via the incorporation of IR absorbing nanomaterials into a textile material is novel, facile, efficient and applicable at any stage of garment manufacture. Hence, it allows us to effectively overcome the limitations faced by existing yarn-level and structural strategies for improved moisture management., (© 2021 The Authors.)

Electrically conductive and biodegradable materials are desired for a range of applications in wearable electronics to address the growing ecological problem of e-waste. Herein, we report on the design and fabrication of all-organic, conductive and biodegradable nanofibrous core-shell yarn produced by in situ polymerization of aniline on the surface of electrospun poly(ε-caprolactone) nanofibers. The effect of concentration of aniline monomer on the morphology and resistivity of deposited polyaniline layer was investigated. The electrical resistance changed almost instantaneously with the strain for multiple stretch and recovery cycles. This rapid and sensitive response to mechanical loading and unloading is promising to validate the possibility of using the conductive yarns as strain sensors for monitoring human motion. Increasing the number of plies of yarn to three resulted in a three-fold reduction of the resistance. The twisted plied yarns were incorporated into fabric by stitching to demonstrate their use as a wearable electrode for capacitive sensors. This approach presents an early step in realizing all-organic conductive biodegradable nanofibrous yarns for biodegradable smart textiles., Competing Interests: The authors declare no conflict of interest., (This journal is © The Royal Society of Chemistry.)

Polyethylene glycol (PEG) based shape-stabilized phase change materials (PCMs) were successfully prepared using chitin nanofibers (CNFs). CNFs were isolated from crab shells and, resulted CNFs were several tenth of nanometers in diameter and had lengths ranging from several hundreds of nanometers to few micrometers. Introduction of CNFs in to PEG resulted shape-stabilized composites. Various PEG-CNF composites were fabricated and the resulted materials were encapsulated in to an optical device to obtain temperature dependent transparency. In the optimized formulation, the device remained opaque (∼3.5 %) below the melting point of the PEG-CNF composite and became gradually transparent as the temperature of the device increased ultimately stabilizing at a transmittance value of ∼88 %. CNF phase was seen to have an effect on the thermal properties of the PEG-CNF material. The work introduces a novel strategy for the shape stabilization of liquid-solid phase change materials unlocking potential for new PCM based devices., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Chitin nanofibers are emerging as a very attractive bio-compatible material in number of advanced materials applications. In this work, the colloidal stability of the chitin nanofibers was investigated against pH, ionic strength, temperature and concentration. Aqueous solutions of chitin nanofibers were found to be stabilized due to the carboxylic acid moieties available in the fibril surface as evidenced by both 13 C NMR and potentiometric titration methods. Amongst others, pH and ionic strength were the most influential factors which determine both hydrodynamic diameter and zeta potential. The chitin nanofiber dispersions were stabilized at pH values higher than 7, with an average zeta potential value of -22.5 mV. A monotonic increase of zeta potential was observed with respect to increase in ionic strength. Zeta potential got stabilized at -14.0 mV for ionic strengths over 20 mM of NaCl. Hydrodynamic particle size was also found to be a function of temperature and concentration., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Electrically conductive cotton fabric was fabricated by in situ one pot oxidative polymerization of aniline. Using a simple heterogeneous polymerization method, polyaniline (PANI) nano fibers with an average fiber diameter of 40-75 nm were grafted in situ onto cotton fabric. The electrical conductivity of the PANI nanofiber grafted fabric was improved 10 fold compared to fabric grafted with PANI nanoclusters having an average cluster size of 145-315 nm. The surface morphology of the cotton fibers was characterized using SEM and AFM. Electrical conductivity of PANI nanofibers on the cotton textile was further improved from 76 kΏ/cm to 1 kΏ/cm by increasing the HCl concentration from 1 M to 3 M in the polymerization medium. PANI grafted cotton fabrics were analyzed using FTIR, and the data showed the presence of polyaniline functional groups on the treated fabric. Further evidence was present for the chemical interaction of PANI with cellulose. Dopant level and morphology dependent electron transition behavior of PANI nanostructures grafted on cotton fabric was further characterized using UV-vis spectroscopy. The electrical conductivity of the PANI nano fiber grafted cotton fabric can be tuned by immersing the fabric in pH 2 and pH 6 solutions for multiple cycles., (Copyright © 2018. Published by Elsevier Ltd.)

Chitin and chitin derivatives have gained significant research interest over the years due to a number of beneficial properties that can be exploited in various application fields. Particularly, interactions between their nanostructures and other nanomaterials are of great interest. In situ photo-reduction of AgCl in chitin nanofiber aqueous dispersions resulted in significant loss of colloidal stability of both chitin nanofibers (CNF) and silver nanoparticles. UV-vis spectroscopy was used to characterize the extinction profiles of in-situ prepared CNF and several silver nanoparticle mixtures over the reaction steps. High resolution TEM characterization of the resulting structures indicated the presence of the aggregated form of nanofiber and nanoparticles. Energy filtered TEM analysis confirmed the existence of both CNF and silver nano particles in the aggregate, with silver in its chemically reduced state (Ag(0)). FT-IR, and 13 C solid state NMR revealed the presence of strong interactions between Ag and CNF through hydroxyl and carbonyl moieties of the CNF structure. It was concluded that these interactions led to the formation of a supramolecular aggregate in the in-situ mixture as a result of wrapping of CNF around photo-reduced silver nanoparticles which resulted in the colloidal instability., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

Acoustic cavitation formed due to propagation of ultrasound wave inside a dye bath was successfully used to dye cotton fabric with a reactive dye at lower temperatures. The energy input to the system during sonication was 0.7 W/cm(2). This was within the energy range that contributes towards forming cavitation during ultra-sonication. The influence of ultrasound treatment on dye particle size and fiber morphology is discussed. Particle size analysis of the dye bath revealed ultra-sonication energy was capable of de-agglomeration of hydrolyzed dye molecules during dyeing. SEM micrograph and AFM topographical image of the fiber surface revealed fiber morphology remains unchanged after the sonication. The study was extended in understanding the contribution of ultrasound method of dyeing towards achieving good color strength on the fabric, compared to the normal heating method of dyeing. Study showed color strength obtained using ultra sound method of dyeing is higher compared to normal heating dyeing. Ultrasound energy was able to achieve the good color strength on cotton fabric at very low temperature such as 30 °C, which was approximately 230% more than the color strength achieved in normal heating method of dyeing. This indicates that energy input to the system using ultrasound was capable of acting as an effective alternative method of dyeing knitted cotton fabrics with reactive dye., (Copyright © 2015 Elsevier B.V. All rights reserved.)

A method of coloration of cotton fabrics with nano chitosan is proposed. Nano chitosan were prepared using crab shell chitin nanofibers through alkaline deacetylation process. Average nano fiber diameters of nano chitosan were 18 nm to 35 nm and the lengths were in the range of 0.2-1.3 μm according to the atomic force microscope study. The degree of deacetylation of the material was found to be 97.3%. The prepared nano chitosan dyed using acid blue 25 (2-anthraquinonesulfonic acid) and used as the coloration agent for cotton fibers. Simple wet immersion method was used to color the cotton fabrics by nano chitosan dispersion followed by acid vapor treatment. Scanning electron microscope and atomic force microscope study of the treated cotton fiber revealed that the nano chitosan were consistently deposited on the cotton fiber surface and transformed in to a thin polymer layer upon the acid vapor treatment. The color strength of the dyed fabrics could be changed by changing the concentration of dyed nano chitosan dispersion., (Copyright © 2015 Elsevier Ltd. All rights reserved.)