Abstract
Conductive hydrogels have garnered significant attention as ideal materials for flexible wearable sensors due to their conductivity, flexibility, adaptability, and biocompatibility. However, traditional conductive hydrogels frequently exhibit poor moisture retention and suboptimal mechanical properties, which greatly limit their practical usability. Inspired by the anisotropic structure of biological tissues and the natural moisturizing factors in skin, a novel bioinspired directional hydrogel (BDH) system is presented, using polyvinyl alcohol as the matrix, incorporating polydopamine-modified carbon nanotubes and PEDOT-PSS as conductive materials, and sodium pyrrolidone carboxylic acid for moisture retention. The precursor solution containing disordered polymer chains undergoes flow-induced alignment, followed by strong aggregation and crystallization driven by a kosmotropic salt solution. This dual-stage process ultimately yields the BDH with pronounced structural anisotropy, characterized by tightly packed, aligned polymer domains. The obtained hydrogel exhibits excellent mechanical strength, damage tolerance, good conductivity, and moisture retention, making it suitable as a flexible sensor for high-load stress conditions. When combined with machine learning algorithms, BDHs enable accurate motion tracking and intent recognition, showing promising applications in motor training and ability assessment. This efficient, energy-saving fabrication method offers a promising strategy for developing bioinspired structural hydrogels, facilitating their practical use in human-machine interactions.