Public health events caused by viruses pose a significant risk to humans worldwide. From December 2019 till now, the rampant novel 2019 coronavirus (SAR-CoV-2) has hugely impacted China and over world. Regarding a commendable means of protection, mask technology is relatively mature, though most of the masks cannot effectively resist the viral infections. The key material of the mask is a non-woven material, which makes the barrier of virus through filtration. Due to the lack of the ability to kill the viruses, masks are prone to cross-infection and become an additional source of infection after being discarded. If the filteration and antiviral effects can be simultaneously integrated into the mask, it will be more effcient, work for a longer time and create less difficulty in post-treatment. This mini-review presents the advances in antiviral materials, different mechanisms of their activity, and their potential applications in personal protective fabrics. Furthermore, the article addresses the future challenges and directions of mask technology.
Disposable medical protective clothing for 2019-nCoV mainly consists of stacked layers with nanopore films, polymer coated nonwoven fabrics and melt-blown nonwoven fabrics against anti-microbial and anti-liquid penetration. However, such structures lack moisture permeability and breathability leading to an uncomfortable, stuffy wearing experience. Here, we propose a novel medical protective clothing material with a superabsorbent layer to enhance moisture absorption. Poly(acrylic acid-co-acrylamide)/polyvinyl alcohol superabsorbent fibers (PAAAM/PVA fibers) were prepared via wet spinning. And the superabsorbent composite layer was stacked from PAAAM/PVA fibers, bamboo pulp fibers (BPF) and ethylene-propylene side by side fibers (ESF). The novel disposable medical protective composite fabric was obtained through gluing the superabsorbent layer to the inner surface of strong antistatic polypropylene nonwoven fabric. The resultant composite fabric possesses excellent absorption and retention capacity for sweat, up to 12.3 g/g and 63.8%, and a maximum hygroscopic rate of 1.04 g/h, higher than that of the conventional material (only 0.53 g/h). The moisture permeability of the novel material reached 12,638.5 g/(m2 d), which was 307.6% of the conventional material. The novel material can effectively reduce the humidity inside the protective clothing and significantly improve the comfort of medical staff.
Rapid NIR light detection and/or writing has drawn much attention, but their practical applications have been limited by obtaining such NIR photodetectors. To address this problem, we have developed a simple and versatile strategy to prepare a non-woven fabric photodetector. The blue non-woven fabric photodetector has been prepared by coating photo-thermochromic ink (including crystal violet lactone (CVL) as the thermo-sensitive dye, polypyrrole (PPy) nanospheres as the photothermal component and hydroxyethyl cellulose (HEC) as the polymer matrix) on white non-woven fabric. When the blue fabric photodetector is irradiated by NIR (808-nm as model, 0.75 W cm−2) laser, the discoloration occurs in 35 s, and higher laser intensity confers more rapid discoloration. This discoloration results from the photothermal effect of PPy which confers the elevation of temperature (> 50 °C) and then converts CVL to its leuco form (colorless). When the laser is turned off, the temperature drops to below the transition temperature (< 43 °C), and then CVL reverts to its initial blue color. Moreover, different figures and images can be easily printed on the fabric photodetector by 808 nm laser, and then they can be erased automatically under ambient conditions, with excellent cycling stability. Therefore, this fabric photodetector may act as a new platform for rapid NIR light detection and writing.
Textiles have proved to be very important materials to human beings since the time immemorial. And, fibers are the basic building units of these materials. In this perspective we substantiate the uniqueness and capability of nanofibers as active layers in face masks, to protect people against the novel coronavirus disease (COVID-19). This time-sensitive letter introduces the mechanisms based on which their active filters function, the uniqueness of electrospun nanofibers in face masks and do-it-yourself (DIY) steps to realize a fully functional face mask at home.
In this work, shape-stabilized solid-solid phase change materials (PCMs) were fabricated by simply electrospinning polyethylene glycol (PEG) and polyvinyl alcohol (PVA). Owing to the strong hydrogen bonds and entanglement between those molecular chains of PEG and PVA, PEG was packaged by PVA. The morphological structures, thermal stability and thermal energy storage properties of those fibers were investigated. SEM results showed that those electrospun PVA/PEG composite membranes hold a three-dimensional nonwoven web structure even the content of PEG as high as 70%. The thermal energy storage ability of those composite fibers increased with the increase of the content of PEG. The heat enthalpies of PEG/PVA = 7/3 were as high as 78.806 J/g. Moreover, those composite fibers had excellent thermal stability. After 100 heating and cooling cycles, there was almost no obvious change in the melting enthalpy and crystallization enthalpy. Those fibers still maintained good thermal regulation. The simple preparation process, low cost of raw materials and excellent stability endow the PCMs great utilization potentiality in smart textile and energy storage systems.
We report a study investigating the effects of thermal annealing on the optical properties of Si-Ge alloy-core silica-cladded fibers. Low temperature fiber draw was performed with a laboratory-made draw tower at 1760 °C that minimizes impurity diffusion from cladding to the core. As a post-drawing process, Si–Ge core fibers were annealed in a box furnace to alter the core structure. Microstructural and optical properties of fibers were investigated, and transmission losses were measured as 28 dB/cm at 6.1 µm. Numerical studies were performed to analyze the experimental results and to find the optimum structure for low loss semiconductor-core glass-cladded fibers.