Directional water transport fabrics with durable ultra-high one-way transport capacity

Fabrics with automatic one-way water transport ability are highly desirable for applications in daily life, industry, health, and defense. However, most of the studies on one-way water transport fabrics only report the qualitative water transport results. The lack of quantitative measure makes it hard to assess the directional transport quality. Here, it is proved that a hydrophilic fabric after being electrosprayed with a thin layer of hydrophobic coating on one side shows one-way water transport ability. By using moisture management tester, the water transport property is qualitatively characterized and the effect of hydrophobic fabric layer thickness on one-way water transport feature is examined. The hydrophobic fabric layer thickness is found to play a key role in deciding the one-way transport ability. When a plain woven fabric with an overall thickness of 420 μm and average pore size of 33 μm is used as fabric substrate, a hydrophobic fabric layer thickness between 22 and 62 μm allows the treated fabric to show a one-way droplet transport feature. A one-way transport index as high as 861 can be attained. The one-way water transport is durable enough to withstand repeated washing. This novel fabric may be useful for development of “smart” textiles for various applications.

Sunlight-induced coloration of silk

Silk fabrics were colored by gold nanoparticles (NPs) that were in situ synthesized through the induction of sunlight. Owing to the localized surface plasmon resonance (LSPR) of gold NPs, the treated silk fabrics presented vivid colors. The photo-induced synthesis of gold NPs was also realized on wet silk through adsorbing gold ions out of solution, which provides a water-saving coloration method for textiles. Besides, the patterning of silk was feasible using this simple sunlight-induced coloration approach. The key factors of coloration including gold ion concentration, pH value, and irradiation time were investigated. Moreover, it was demonstrated that either ultraviolet (UV) light or visible light could induce the generation of gold NPs on silk fabrics. The silk fabrics with gold NPs exhibited high light resistance including great UV-blocking property and excellent fastness to sunlight.

Conductive polymer coatings

Conducting polymer-coated textiles possess a wide range of electrical properties. The surface resistivity is influenced by concentrations of the reactants, the thickness of the coating, the nature of the substrate surface, the extent of penetration of the polymer into the textile structure, and the strength of the binding of the coating to the textile surface. Low resistivity in fabric results from highly doped thicker coatings that penetrate well into the textile structure, thus enabling good electrical contact between fibers. Microwave studies showed that conductive textiles are not highly effective as electromagnetic shielding materials owing to their medium-level conductivity and therefore large skin depth. Combined with the fact that coatings are around 1. ?m thick, they cannot act as effective reflective barriers to electromagnetic radiation. However, because they are highly absorptive in the microwave region, absorbing materials can be designed in conjunction with conductive textiles. Study of Fourier transform-infrared spectra of aged polypyrrole films has shown an increase in intensity of an ?,?-unsaturated conjugated carbonyl peak that may be linked to the increase in resistance but cannot be the only factor, because the rate of electrical decay was influenced by several factors such as temperature, the type and concentration of the dopant, and the aging time, all of which signify a complex mechanism of degradation of conductivity. Degradation is a major concern for conductive textile systems that needs to be characterized before considering these materials for potential applications.

Evolution of 3D printed soft actuators

Developing soft actuators and sensors by means of 3D printing has become an exciting research area. Compared to conventional methods, 3D printing enables rapid prototyping, custom design, and single-step fabrication of actuators and sensors that have complex structure and high resolution. While 3D printed sensors have been widely reviewed in the literature, 3D printed actuators, on the other hand, have not been adequately reviewed thus far. This paper presents a comprehensive review of the existing 3D printed actuators. First, the common processes used in 3D printing of actuators are reviewed. Next, the existing mechanisms used for stimulating the printed actuators are described. In addition, the materials used to print the actuators are compared. Then, the applications of the printed actuators including soft-manipulation of tissues and organs in biomedicine and fragile agricultural products, regenerative design, smart valves, microfluidic systems, electromechanical switches, smart textiles, and minimally invasive surgical instruments are explained. After that, the reviewed 3D printed actuators are discussed in terms of their advantages and disadvantages considering power density, elasticity, strain, stress, operation voltage, weight, size, response time, controllability, and biocompatibility. Finally, the future directions of 3D printed actuators are discussed.

Facile fabrication of polyester filament fabric with highly and durable hydrophilic surface by microwave-assisted glycolysis

Poly(ethylene terephthalate) (PET) fabric with highly and durable hydrophilic surface was fabricated using microwave-assisted glycolysis. Sodium hydroxide (NaOH) as a catalyst was proven to be suitable for PET glycolysis under assistance of microwave. The modified PET fabric (0.5% NaOH, irradiation 120 s) showed high surface hydrophilicity with a contact angle of 17.4 ° and a wicking length of 19.36 mm. The exposure of the carboxyl- and hydroxyl-end groups on the surface of PET and the introduction of etches were confirmed by Methylene Blue staining and field emission scanning electron microscopy (FESEM), receptively. Although the strength of PET fabric decreased after modification, it was still high enough for textile applications. The thermal properties of the modified PET fabrics were well maintained. The high hydrophilicity and its original properties of PET could be controlled by changing the irradiation time from 60 s to 120 s and adjusting the content of sodium hydroxide from 0.2% to 0.5%. These results suggest microwave-assisted glycolysis with sodium hydroxide is an effective method for PET hydrophilic finishing.

Separation and development of polymer blends: an environmentally friendly approach

This work has demonstrated a facile route to separate polyester/cotton blend textile waste by a chemical dissolution method. The recovered cellulose from textile waste were used to regenerate a novel composite fibre with improved properties which could potentially be used in textile applications.

Heat and moisture transfer through silkworm cocoon walls.

A silkworm cocoon is a biological porous structure which provides multiple protective functions. The knowledge from this natural protective system could contribute to develop advanced materials and structures with superior performances and meet the human demanding of novel breathable materials for enhanced thermal protection and comfort.

Bifacial fabric structures and properties.

Novel bifacial fabrics, with a woven structure on one face and a knitted structure on the other, were developed and produced on a purpose-built machine using conventional fibres. Bifacial fabrics have two breakages in warp and weft directions, and better thermal comfort properties than traditional woven and knitted fabrics.

Photocatalytic TiO2/porous BNNSs composites for textile dyeing wastewater treatment

This project develops a novel photocatalyst for the cleaning of textile dyeing wastewater. The newly-developed photocatalyst was prepared by combing porous boron nitride nanosheets with titanium dioxide particles and these composites show potentials for the practical treatment of the textile dyeing wastewater in a large scale.