Dual-mode COFs@CNTs-based hydrogel: real-time motion monitoring and efficient solar desalination

Hydrogels have attracted extensive attention due to their potential applications in wearable electronic devices and solar-driven water evaporation. Herein, we developed a multifunctional COFs-based hydrogel (VCOF-1@CNT-Gel), by vinyl-functionalized COFs composite (VCOF-1@CNT) as a covalent cross-linker. As a result, this innovative design optimizes electrical conductivity and light absorption (97.3%). On the one hand, the VCOF-1@CNT-Gel can be assembled as strain sensors with a wide working strain range of up to 300%, high and strain-dependent sensitivity (gauge factor tunable from 1.4 to 3.2), and rapid response (<200 ms), enabling precise monitoring of various human movements. On the other hand, the VCOF-1@CNT-Gel evaporator achieves an evaporation rate of 2.21 kg·m^-2·h^-1 while maintaining a photothermal efficiency exceeding 90% under one sun irradiation. During the solar desalination, the excellent photocatalytic activity by the VCOF-1@CNT endows the VCOF-1@CNT-Gel with exceptional photocatalytic degradation ability. Outdoor tests further validate its efficacy in desalination and agricultural irrigation, producing freshwater that supports healthy plant growth. These results demonstrate that VCOF-1@CNT-Gel hydrogel has great potential for applications in wearable electronics, solar water purification, and agricultural development.