Carboxymethyl cellulose hydrogels for flexible electronics: From design to applications

Carboxymethyl cellulose (CMC)-based hydrogels have emerged as a leading sustainable material platform for flexible electronics, distinguished by their renewable origin, excellent biocompatibility, and highly tunable physicochemical properties. This review explores material design strategies and application frontiers of CMC hydrogel-based flexible sensors, providing a critical analysis of the structure-property-application relationships. It begins by examining the unique molecular features of CMC that enable diverse chemical modifications and versatile network formation. The review then examines advanced fabrication approaches, focusing on dual-network and multi-modal crosslinking strategies. These designs synergistically combine dynamic non-covalent with stable covalent interactions to achieve breakthrough performance in mechanical robustness, self-healing, and environmental adaptability. The analysis demonstrates their remarkable sensing capabilities across physical, chemical, and biological domains, highlighting their role in enabling high-performance, skin-conformal electronic devices. Finally, the review presents a perspective on intelligent, multifunctional sensing systems, outlining how CMC hydrogels are poised to advance next-generation flexible electronics.