Smart molecular design for functional cellulose gels and flexible devices

Cellulose, the dominant natural polymer on Earth, features a distinct molecular structure with extraordinary mechanical properties and tunable characteristics, making it attractive for gel systems. Although significant progress has been made, challenges remain in fully leveraging their functional potential and broadening practical applications. This review systematically examines the properties of cellulose and cellulose gels, exploring novel reinforcement strategies-across molecular, supramolecular network, and macroscale structure levels-to enhance mechanical, electrical, and thermal performance, while coordinating these properties for practical implementations. These advancements are exemplified in emerging fields such as flexible robotics, electronic skins, flexible energy storage devices, and human-machine interaction systems. This article thoroughly investigates the fundamental characteristics, multi-scale design approaches, performance enhancement mechanisms, and cutting-edge implementations of cellulose-based gels across diverse domains. It provides a comprehensive overview of these advanced materials and offers strategic insights and recommendations for future research and innovation.