Graphene Implanted Shape Memory Polymers with Dielectric Gene Dominated Highly Efficient Microwave Drive

Microwave-driven strategy shows many advantages including selective energization, uniform heating, and high penetration depth, which is a hot topic in wireless actuators. Understanding microwave stimulus-response mechanisms is the key to developing universal construction strategies for advanced microwave-driven actuators. Herein, reduced graphene oxide (rGO) with specified dielectric genes and thermal properties is implanted into the shape memory polymer, liquid crystal elastomer (LCE) as an example, to construct soft, reversible, and sensitive microwave actuators. Based on the analysis of microstructure and dielectric properties, LCE-rGO composites exhibit excellent polarization relaxation-dominated dielectric loss and electromagnetic (EM) energy conversion ability. The maximum dielectric loss factor (epsilon '') and loss tangent (tan delta(e)) of LCE-rGO are dramatically increased by 216% and 87.5% compared to pure LCE, respectively, and the optimum apparent energy harvest efficiency is 19.4 times higher than that of LCE. In addition, the implantation of rGO significantly lowers the microwave actuation threshold of LCE-rGO composites and reinforces their stimulus-response capacity. Response time under 750 W microwave irradiation of LCE-rGO is shortened to <10s. These findings can provide a solid basis for the design and fabrication of highly efficient microwave stimuli-responsive polymers and enlighten a new approach to wireless actuated smart devices.

Automated summary

The microwave-driven strategy for actuators has advantages of selective energization, uniform heating, and high penetration depth. Understanding the microwave stimulus-response mechanisms is crucial for developing universal construction strategies. The study focuses on implanting reduced graphene oxide (rGO) into liquid crystal elastomer (LCE) to construct soft and sensitive microwave actuators. The LCE-rGO composites demonstrate excellent polarization relaxation-dominated dielectric loss and electromagnetic energy conversion ability. Additionally, the implantation of rGO lowers the actuation threshold and shortens the response time of LCE-rGO.