Hydrogel-based flexible electronic devices have great potential in human motion monitoring, electronic skins, and human-computer interaction applications; hence, the efficient preparation of highly sensitive hydrogel-based flexible sensors is important. In the present work, the ultrafast polymerization of a hydrogel (1–3 min) was achieved by constructing a tannic acid (TA)-Fe³⁺ dynamic redox system, which endowed the hydrogel with good adhesion performance (the adhesion strength in wood was 17.646 kPa). In addition, the uniform dispersal ensured by incorporating polydopamine-decorated polypyrrole (PPy@PDA) into the hydrogel matrix significantly improved the hydrogel’s stretching ability (575.082%). The as-prepared PAM/CS/PPy@PDA/TA hydrogel-based flexible sensor had a high-fidelity low detection limit (strain = 1%), high sensitivity at small strains (GF = 5.311 at strain = 0–8%), and fast response time (0.33 s) and recovery time (0.25 s), and it was reliably applied to accurate human motion monitoring and handwriting recognition. The PAM/CS/PPy@PDA/TA hydrogel opens new horizons for wearable electronic devices, electronic skins, and human-computer interaction applications.

Waterborne acrylic resin is widely used as a binder of waterborne printing ink because of its excellent comprehensive properties. However, its further developments and applications are hindered by its poor UV resistance and water resistance. Therefore, an approach to prepare acrylic resin with excellent UV resistance and water resistance is described in this present study. The nano-TiO₂/SiO₂ composite particles were first modified with a silane coupling agent (KH-570) and a titanate coupling agent (NDZ-101) and then embedded into acrylic resin via a blending method. Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), and thermogravimetry analysis (TGA) were applied to investigate the structure and morphology of the modified nano-TiO₂/SiO₂ composite particles. The effects of the modified nano-TiO₂/SiO₂ composite particles on the UV and water resistance of the acrylic resin were investigated by UV spectroscopy and water resistance analysis. The weight loss of modified nano-TiO₂/SiO₂ was about 20% when heated to 600°C, which indicated that the nano-TiO₂/SiO₂ composite particles were modified by the coupling agents successfully. The UV-Vis spectra of acrylic resin showed that the UV resistance was improved upon the addition of nano-TiO₂/SiO₂. The water absorption of the nano-TiO₂/SiO₂-acrylic resin was less than 5%, indicating that the water resistance of the material was improved.