Photo-, Thermal-, and Electro-Responsive Polyolefin-Based Actuators

Stimuli-responsive polymeric actuators have been applied in soft robotics and artificial muscles. Although numerous functional polymers are used during actuator fabrication, the utilization of low-cost and industrially scalable polyolefins has remained largely unexplored. This study presents a facile in situ polymerization strategy to fabricate multifunctional polyolefin-based actuators with exceptional mechanical strength, rapid stimuli-responsiveness, and ultrahigh work capacities. By developing PANI/CNTs-COOH composite fillers as catalytic supports for α-diimine nickel catalysts, in situ ethylene polymerization was used to produce a uniform dispersion of functional fillers within a branched polyethylene matrix. This overcame the phase separation inherent to traditional blending methods. The resulting composites demonstrated remarkable mechanical properties, reaching a maximum tensile stress of 135 MPa after training, a tunable electrical conductivity, and a high photothermal conversion efficiency. These properties enabled self-healing and triple-stimuli-responsive shape-memory behavior. When used as actuators, these materials exhibited programmable actuation with a work capacity of 470.4 J kg^-1.