Unparalleled Armour for Aramid Fiber with Excellent UV Resistance in Extreme Environment

A triple-crosslinking strategy for high-performance regenerated cellulose fibers derived from waste cotton textiles

Regenerated cellulose fibers has attracted increasing attention for high-grade textile raw materials and industrial textiles, but the low mechanical property caused by differences in regenerated raw materials and production levels limits its commercial application in the product diversity. Herein, we proposed a novel triple-crosslinking strategy by coupling with hydrogen bonds, chemical crosslinking, and internal mineralization from multiple pulsed vapor phase infiltration (MPI) to improve the mechanical performance of regenerated cellulose fibers. A binary solvent composed of ionic liquid (IL) and dimethyl sulfoxide (DMSO) is used to dissolve waste cotton textile and then wet spinning. Dual-crosslinking is firstly achieved by coupling glutaraldehyde (GA) and cellulose reaction. Subsequently, a metal oxide is intentionally infiltrated into inner cellulosic through MPI technology to form a third form of crosslinking, accompanied by the ultra-thin metal oxide nano-layer onto the surface of regenerated cellulose fibers. Results showed that the triple-crosslinking strategy has increased the tensile stress of the fiber by 43.57 % to 287.03 MPa. In all, triple-crosslinking strategy provides a theoretical basis and technical approach for the reinforcement of weak fibers in waste cotton recycling, which is expected to accelerate the development of the waste textile recycling industry and promote of the added-value of regenerated products.

Confined Water Dominates Ion/Molecule Transport in Hydrogel Nanochannels

Current artificial nanochannels rely more on charge interactions for intelligent mass transport. Nevertheless, popular charged nanochannels would lose their advantages in long-term applications. Confined water, an indispensable transport medium in biological nanochannels, dominating the transport process in the uncharged nanochannels perfectly provides a new perspective. Herein, we achieve confined-water-dominated mass transport in hydrogel nanochannels (HNCs) constructed by in situ photopolymerization of acrylic acid (PAA) hydrogel in anodic alumina (AAO) nanochannels. HNCs show selectivity to Na+ transport and a high transport rate of molecules after introducing Na+/Li+, compared with other alkali metal ions like Cs+/K+. The mechanism given by ATR-FTIR shows that the hydrogen-bonding structure of confined water in HNCs is destabilized by Na+/Li+, which facilitates mass transport, but is constrained by Cs+/K+, resulting in transport inhibition. This work elucidates the relationship between confined water and mass transport in uncharged nanochannels while also presenting a strategy for designing functional nanochannel devices.

Perfect absorption based on a ceramic anapole metamaterial

Metamaterials, from concept to application level, is currently a high-trending topic. Due to the strict requirements of the simultaneous reasonable structural design and stability of materials, the construction of a high-performance metamaterial for extreme environments is still difficult. Here, combining metamaterial design with materials optimization, we propose a completely different strategy and synthesize a type of monomeric ceramic meta-atom to construct metamaterials. Based on a geometric design with multiple degrees of freedom and dielectric properties, hybrid anapole modes with impedance matching can be produced, experimentally inducing nearly perfect absorption with high temperature stability (high tolerable temperature of approximately 1300 °C, with almost zero temperature drift) in microwave/millimeter-wave bands. We surpass the oxidation temperature limitation of 800 °C in conventional plasmonic absorbers, and provide an unprecedented direction for the further development of integrated high-performance metamaterial wireless sensors responding to extreme environmental scenarios, which will also lead to a new direction of specific ceramic research toward device physics.

Study on cellulose nanofibers/aramid fibers lithium-ion battery separators by the heterogeneous preparation method

In this study, a heat-resistant and high-wettability lithium-ion batteries separator (PI-CPM-PI) composed of cellulose nanofibers (CNF) and aramid fibers (PMIA chopped fiber/PPTA pulp) with the reinforced concrete structure was fabricated via a traditional heterogeneous paper-making process. CNF played crucial roles in optimizing the pore structure and improving the wettability of PI-CPM-PI separator. The effects of composition on separator properties were investigated and the results indicated that the optimal compositions were 0.5 wt% CNF, 0.5 wt% PMIA chopped fiber/PPTA pulp (ratio of 5:5), 0.05 wt% diatomite and 1.5 wt% polyimide. Relevant tests demonstrated that the performance advantages of PI-CPM-PI separators were exhibited at the wettability and thermal stability compared to the commercial separator (PP). Additionally, batteries assembled with PI-CPM-PI separators showed excellent electrochemical and cycling performance (ionic conductivity of 1.041 mS.cm^-1, the first discharge capacity of 158.2 mAh.g^-1 at 0.2C and capacity retention ratio of 99.76 % after 100 cycles).

Superdurable and fire-retardant structural coloration of carbon nanotubes

Carbon nanotubes (CNTs) are promising candidates for numerous cutting-edge fields because of their excellent properties. However, the inherent black color of CNTs cannot satisfy the aesthetic/fashion requirement, and the flammability of CNTs severely restricts their application in high-temperature environments with oxygen. Here, we realized a structural coloration of CNTs by coating them with amorphous TiO₂ layers. By tuning the TiO₂ coating thickness, both CNT fibers and membranes exhibited controllable and brilliant colors, which exhibited remarkable superdurability that could endure 2000 cycles of laundering tests and more than 10 months of high-intensity ultraviolet irradiation. The TiO₂-coated CNTs exhibited a notable fire-retardant performance and could endure 8 hours of fire burning. The structural coloration of CNTs with excellent fire retardance substantially improves their performance and broadens their applications.