Strong and Ultra-Tough Hydrogel with Hierarchical Cross-Linking Network Architecture Constructed by a Hyperbranched Topological Structure

Abstract

Natural biological tissues such as jellyfish integrate hierarchical architectures with multifunctionality (e.g., bioluminescence, mechanical resilience, and responsiveness), yet replicating such synergy in synthetic hydrogels remains a significant challenge. Here, we present a bioinspired hydrogel engineer that employs a hyperbranched macro-cross-linker as a topological regulator to precisely manipulate the hierarchical cross-linking network architecture. Compared to the linear macro-cross-linker, the introduction of a hyperbranched topological structure has endowed the hydrogel with excellent mechanical properties. By systematically tuning branching parameters (DB and S_n), we further achieve simultaneous modulation of both the microphase separation morphology and multistage cross-linking networks. With moderate DB and S_n, the hydrogel exhibits an optimal hierarchical structure and the most uniform microphase separation, achieving the integration of excellent mechanical performance, remarkable unconventional fluorescence emission, and notable conductivity. Furthermore, the hydrogel demonstrates highly sensitive dual optical–electrical responsive behaviors when used as a strain sensor. This strategy provides a universal platform for designing hierarchical hydrogels with programmable functionality, offering promising material for advanced applications in bioelectronics and soft robotics.