AgNPs@Dopamine@BN/Chitosan nanopaper for a novel soft actuator: Dual thermal/electrical triggered shape memory, efficient flame retardancy and thermal management

Currently, chitosan (CS)-based shape memory materials typically require the incorporation of reversible phases, which impair CS’s intrinsic properties. This study proposed a facile strategy to solve this problem: replacing the traditional organic reversible phases with novel functional inorganic nanomaterials. Hexagonal boron nitride (h-BN) nanosheets were modified with silver nanoparticles (AgNPs) and then used to fabricate the AgNPs@dopamine@BN/chitosan nanopaper (BDAC), a dual thermal- and electrical-triggered shape memory nanocomposite. The results show that BDAC-1 has a thermal conductivity of 1.38 W/(mK)—a 138% increase compared to neat CS—and a good electrical conductivity of 35.6 S/cm. A triple-folded BDAC-1 sample (1 × 4 cm²) fully recovered to a flat state in 43 s on a 120 °C heating platform, reaching 91.5 °C internally. Under 8.5 V, it achieved full shape recovery in 132 s, with an internal temperature of 96.7 °C. The peak heat release rate (pHRR) of BDAC-1 is only 21.4 W/g, which has decreased by 39.5% compared with the neat CS, revealing significantly improved flame retardancy. In addition, BDAC presents high-efficient thermal management performance, which alleviates the risks of heat accumulation and fire. Furthermore, we demonstrated the versatile applicability of BDAC by integrating it into thermal/electrical dual-triggered hierarchical alarm devices and micro-mechanical grippers, highlighting the exceptional application potential of this high-performance soft actuator.