Leaf Hierarchical Venation Network‐Mimetic Elastomer for Dual‐Mode Synergistic Respiration Monitoring

Abstract Natural materials often exhibit diverse and unique properties due to their hierarchical ordering architectures. However, replicating such integral ordered structures in synthetic elastomers through a facile and low‐energy approach remains a significant challenge. Here, the structural units of a leaf are mimicked through a bottom‐up assembly strategy to construct the hierarchical venation network of dicotyledonous leaves. This design achieves exceptional mechanical strength (11.70 ± 0.34 MPa tensile strength) and ionic conductivity (2.51 × 10 −2 ± 1.89 × 10 −3 S m −1 ) through four cooperative mechanisms: carboxymethyl chitosan (CMCS) emulating cellulose's β‐(1→4)‐glycosidic backbone for reinforcement, copper ions (Cu 2+ ) coordination mimicking lignin's toughening function, carboxylated styrene‐butadiene rubber (XSBR) providing leaf‐mesophyll‐like elasticity while deep eutectic solvent (DES)‐percolated ion channels enabling efficient charge transport. In addition, the biomimetic venation network exhibits a thickness increase of 1.21 nm upon moisture absorption, leading to widened ion channels and consequently improved conductivity. Concurrently, the absorbed moisture decreases the viscosity of DES, facilitating the mobility of ions and molecular chains. Utilizing this synergism, the leaf‐inspired elastomer exhibits exceptional humidity‐responsive characteristics while achieving dual‐mode monitoring of both voltage and resistance signals.