Synergistic enhancement of thermal conductivity and temperature sensitivity in P(DMAA-co-AAM)/h-BN ionogels for high-performance flexible thermal sensing

The rapid evolution of high-power flexible electronics necessitates materials that concurrently enable efficient heat dissipation and high-precision thermal monitoring. Conventional ionogels suffer from intrinsically low thermal conductivity, which induces severe thermal hysteresis, fundamentally compromising their accuracy in dynamic thermal detection. Herein, rather than treating copolymer regulation or h-BN filling as isolated design elements, we propose a thermally coupled ionogel design aimed at reconciling two usually conflicting requirements: rapid heat equilibration and high thermoresistive sensitivity. P(DMAA-co-AAM)/h-BN composite ionogels are fabricated via in-situ UV-initiated free-radical polymerization, in which N,N-dimethylacrylamide (DMAA) and acrylamide (AAM) form a mechanically compliant and ion-transportable copolymer network, lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) provides thermally activated ionic pathways, and hexagonal boron nitride (h-BN) nanosheets introduce filler-assisted thermal transport pathways. Systematic optimization reveals that a DMAA-to-AAM mass ratio of 3:1 with 20 wt% h-BN yields the optimal synergy among mechanical flexibility, thermal transport, and ionic conduction. The resulting composite achieves a thermal conductivity of 0.469 W/(m·K), representing a ∼160% enhancement over the pristine matrix, which effectively suppresses heat accumulation. Concurrently, the ionogel exhibits an ultra-high temperature coefficient of resistance (TCR) of −13.5%/°C and a thermosensitive coefficient (B value) of 3879 K within 0-20°C. Benefiting from the enhanced thermal transport performance, the dynamic thermal response speed of this series of ionogel sensors (30°C → 35°C) is significantly accelerated with the increase of h-BN loading: the T90 response time of the 10 wt%, 20 wt%, and 30 wt% h-BN samples is 32.40 s, 24.34 s, and 15.14 s respectively. Meanwhile, the devices can still maintain stable and reversible resistance switching characteristics over 50 heating-cooling cycles. This study achieves the synergistic enhancement of the thermal management and temperature sensing performance of the ionogel, providing an ideal material platform for the next-generation wearable electronic devices and intelligent thermal management systems.