Phys.org March 29, 2024 Hyper elastic materials exhibit a nonlinear elastic response to large strains, whereas hydrogels typically possess a low elastic range due to the nonuniform cross-linking and limited chain segments among cross-links. An international team of researchers (USA, China) developed a hyperplastic hydrogel that possesses a broader elastic range by introducing a reversible pearl-necklace structure, in which beads are connected by strings. The subnanometric beads could efficiently unfold and refold under cyclic mechanical strains; thus, the hydrogel could rapidly recover after being stretched to an aerial strain of more than 10,000%. It could quickly heal from minor mechanical […]
Tag Archives: Hydrogel
‘Countercation engineering’ for thermoresponsive graphene-oxide nanosheets
Phys.org August 31, 2023 Thermoresponsive graphene-oxide (GO) nanosheets have been widely employed to develop smart membranes/surfaces, hydrogel actuators, recyclable systems, and biomedical applications. Current synthetic strategies to generate thermoresponsive GO nanosheets have exclusively relied on the covalent or non-covalent modification of their surfaces with thermoresponsive polymers. Researchers in Japan discovered that GO nanosheets with Bu4N+ countercations became thermoresponsive in water without the use of any thermoresponsive polymers, inducing a reversible sol–gel transition via their self-assembly and disassembly processes. The resultant dispersion can be used as a direct writing ink for constructing a three-dimensionally designable gel architecture of the GO nanosheets. […]
Intelligent rubber materials
Nanowerk July 18, 2023 Researchers in Germany have developed intelligent humidity-programmed hydrogel patches with high stretchability and tunable water-uptake and -release by copolymerization and crosslinking of N-isopropylacrylamide and oligo(ethylene glycol) comonomers. The intelligent elastomeric patches strongly responded to different humidities and temperatures in terms of mechanical properties which made them applicable for soft robotics and smart skin applications where autonomous adaption to environmental conditions was a key requirement. Beyond using the hydrogel in the conventional state in aqueous media, the new patches could be controlled by relative humidity. The humidity programming of the patches allowed to tune drug release kinetics, […]
This salty gel could harvest water from desert air
MIT News June 15, 2023 Hygroscopic hydrogels are emerging as scalable and low-cost sorbents for atmospheric water harvesting, dehumidification, passive cooling, and thermal energy storage. However, devices using these materials still exhibit insufficient performance, partly due to the limited water vapor uptake of the hydrogels. Researchers in Germany synthesized hygroscopic hydrogels with extremely high salt loadings by tuning the salt concentration of the swelling solutions and the cross-linking properties of the gels. This resulted in unprecedented water uptakes at relative humidity. At 30% RH, the uptake exceeded previously reported water uptakes of metal–organic frameworks by over 100% and of hydrogels […]
Freshwater from thin air
Science Daily February 28, 2022 Hygroscopic materials have attracted widespread attention because of their water harvesting performance. However, the introduction of many inorganic salts often leads to aggregation and leakage issues in practical use. Researchers at UT Austin have developed polyzwitterionic hydrogels as an effective Atmospheric Water Harvesting (AWH) material platform. Via anti-polyelectrolyte effects, the hygroscopic salt coordinated with polymer chains could capture moisture and enhance the swelling property, leading to a strong moisture sorption capacity. The hydrogel showed (0.62 g g−1, 120 minutes for equilibrium at 30 % relative humidity) and produced 5.87 L kg−1 freshwater per day. According to the researchers […]