Facile preparation of highly stretchable hydrogels with low Young's modulus and good fatigue resistance as strain sensors.

Flexible solid-state rechargeable batteries have attracted extensive attention for their potential to accommodate the deep integration of humans and flexible electronics. To achieve a wide operating temperature range of −20 to 70 °C as well as good flexibility and safety, a novel flexible and rechargeable solid-state aqueous Zn−air battery was developed and is reported herein. This battery possessed temperature-resistance, long-term stability, excellent flexibility and mechanical properties, low interfacial resistance, and good safety. The Zn−air battery exhibited a power density of 11.8 mW cm −2 , a specific capacity of 663.25 mA h g −1 , and a gravimetric energy density of 769.37 W h kg −1 at 1 mA cm −2 and 25 °C. During operation at 0 and −20 °C, the maximum output power density retentions of the battery were 80.13% and 67.87%, respectively, compared with that at 25 °C. Furthermore, the battery could consistently power a timer under various conditions, including temperatures of −30 and 70 °C as well as exposure to the flame of an alcohol burner and being subjected to impacts, cutting, or bending. Notably, the battery was able to operate in these scenarios without developing smoke and blast phenomena, thus demonstrating that this battery has significant potential for future applications in safely wearable and flexible electronics that could be employed in harsh temperature environments. These applications would have relevance in a wide variety of fields, such as electric vehicles, aerospace technology, and the military.

The current study is aimed at investigating the effect of cationic charge density and hydrophobicity on the antibacterial and hemolytic activities. Two kinds of cationic surfmers, containing single or double hydrophobic tails (octyl chains or benzyl groups), and the corresponding homopolymers were synthesized. The antimicrobial activity of these candidate antibacterials was studied by microbial growth inhibition assays against Escherichia coli, and hemolysis activity was carried out using human red blood cells. It was interestingly found that the homopolymers were much more effective in antibacterial property than their corresponding monomers. Furthermore, the geminized homopolymers had significantly higher antibacterial activity than that of their counterparts but with single amphiphilic side chains in each repeated unit. Geminized homopolymers, with high positive charge density and moderate hydrophobicity (such as benzyl groups), combine both advantages of efficient antibacterial property and prominently high selectivity. To further explain the antibacterial performance of the novel polymer series, the molecular interaction mechanism is proposed according to experimental data which shows that these specimens are likely to kill microbes by disrupting bacterial membranes, leading them unlikely to induce resistance.