Spider-silk-inspired strong and tough hydrogel fibers with anti-freezing and water retention properties.

Ideal hydrogel fibers with high toughness and environmental tolerance are indispensable for their long-term application in flexible electronics as actuating and sensing elements. However, current hydrogel fibers exhibit poor mechanical properties and environmental instability due to their intrinsically weak molecular (chain) interactions. Inspired by the multilevel adjustment of spider silk network structure by ions, bionic hydrogel fibers with elaborated ionic crosslinking and crystalline domains are constructed. Bionic hydrogel fibers show a toughness of 162.25 ± 21.99 megajoules per cubic meter, comparable to that of spider silks. The demonstrated bionic structural engineering strategy can be generalized to other polymers and inorganic salts for fabricating hydrogel fibers with broadly tunable mechanical properties. In addition, the introduction of inorganic salt/glycerol/water ternary solvent during constructing bionic structures endows hydrogel fibers with anti-freezing, water retention, and self-regeneration properties. This work provides ideas to fabricate hydrogel fibers with high mechanical properties and stability for flexible electronics.

Continuous Spinning of High-Tough Hydrogel Fibers for Flexible Electronics by Using Regional Heterogeneous Polymerization.

Hydrogel fibers have attracted substantial interest for application in flexible electronics due to their ionic conductivity, high specific surface area, and ease of constructing multidimensional structures. However, universal continuous spinning methods for hydrogel fibers are yet lacking. Based on the hydrophobic mold induced regional heterogeneous polymerization, a universal self-lubricating spinning (SLS) strategy for the continuous fabrication of hydrogel fibers from monomers is developed. The universality of the SLS strategy is demonstrated by the successful spinning of 10 vinyl monomer-based hydrogel fibers. Benefiting from the universality of the SLS strategy, the SLS strategy can be combined with pre-gel design and post-treatment toughening to prepare highly entangled polyacrylamide (PAM) and ionic crosslinked poly(acrylamide-co-acrylic acid)/Fe3+ (W-PAMAA/Fe3+ ) hydrogel fibers, respectively. In particular, the W-PAMAA/Fe3+ hydrogel fiber exhibited excellent mechanical properties (tensile stress > 4 MPa, tensile strain > 400%) even after 120 days of swelling in the pH of 3-9. Furthermore, owing to the excellent multi-faceted performance and one-dimensionality of W-PAMAA/Fe3+ hydrogel fibers, flexible sensors with different dimensions and functions can be constructed bottom-up, including the one-dimensional (1D) strain sensor, two-dimensional (2D) direction sensor, three-dimensional (3D) pressure sensor, and underwater communication sensor to present the great potential of hydrogel fibers in flexible electronics.

Enhancement of Proton Conductivity Performance in High Temperature Polymer Electrolyte Membrane, Processed the Adding of Pyridobismidazole.

A pyridobisimidazole unit was introduced into a polymer backbone to obtain an increased doping level, a high number of interacting sites with phosphoric acid and simple processibility. The acid uptake of poly(pyridobisimidazole) (PPI) membrane could reach more than 550% (ADL = 22), resulting in high conductivity (0.23 S·cm-1 at 180 °C). Along with 550% acid uptake, the membrane strength still held 10 MPa, meeting the requirement of Proton Exchange Membrane (PEM). In the Fenton Test, the PPI membrane only lost around 7% weight after 156 h, demonstrating excellent oxidative stability. Besides, PPI possessed thermal stability with decomposition temperature at 570 °C and mechanical stability with a glass transition temperature of 330 °C.

Link between environmental air pollution and allergic asthma: East meets West.

With the levels of outdoor air pollution from industrial and motor vehicle emissions rising rapidly in the fastly-industrializing countries of South East Asia, the prevalence of asthma and allergic diseases has also been increasing to match those in the West. Epidemiological and experimental exposure studies indicate a harmful impact of outdoor air pollution from vehicles and factories both on the development of allergic diseases and asthma and the increase in asthma symptoms and exacerbations. The level of outdoor pollution in Asia is much higher and more diverse than those encountered in Western countries. This may increase the impact of outdoor pollution on health, particularly lung health in Asia. This review discusses the constituents of air pollution in Asia with a special focus on studies in mainland China and Taiwan where the levels of pollution have reached high levels and where such high levels particularly in winter can cause a thick haze that reduces visibility. The onus remains on regulatory and public health authorities to curb the sources of pollution so that the health effects on the population particularly those with lung and cardiovascular diseases and with increased susceptibility can be mitigated.

Mechanistic impact of outdoor air pollution on asthma and allergic diseases.

Over the past decades, asthma and allergic diseases, such as allergic rhinitis and eczema, have become increasingly common, but the reason for this increased prevalence is still unclear. It has become apparent that genetic variation alone is not sufficient to account for the observed changes; rather, the changing environment, together with alterations in lifestyle and eating habits, are likely to have driven the increase in prevalence, and in some cases, severity of disease. This is particularly highlighted by recent awareness of, and concern about, the exposure to ubiquitous environmental pollutants, including chemicals with oxidant-generating capacities, and their impact on the human respiratory and immune systems. Indeed, several epidemiological studies have identified a variety of risk factors, including ambient pollutant gases and airborne particles, for the prevalence and the exacerbation of allergic diseases. However, the responsible pollutants remain unclear and the causal relationship has not been established. Recent studies of cellular and animal models have suggested several plausible mechanisms, with the most consistent observation being the direct effects of particle components on the generation of reactive oxygen species (ROS) and the resultant oxidative stress and inflammatory responses. This review attempts to highlight the experimental findings, with particular emphasis on several major mechanistic events initiated by exposure to particulate matters (PMs) in the exposure-disease relationship.