Nanostructured Block Polymer Muscles Exhibiting Reversible Actuation

Advances in functional soft material actuators that contract, expand, or rotate when triggered with an external stimulus are necessary to realize the future of new robotic assemblies with superior biologically relevant functions. Current research efforts are focused on synthesizing new soft materials to mimic natural muscles from a performance perspective, but neglect the impact of chemical composition and structure hierarchy, which are core features for the exceptional actuation properties of human muscles. Here, the presentation will cover a new class of fiber actuators that contract or rotate when triggered by heat or hydration. The fibers are produced by combining solution-phase block copolymer self-assembly and strain-programmed crystallization. The strained fibers consist of highly aligned nanoscale structures with alternating crystalline and amorphous domains, resembling the ordered and striated pattern of mammalian skeletal muscles. The nanostructured block copolymer muscles exhibit exceptional actuation properties, outperforming many current polymer actuators. The presentation will cover the nanoscale self-assembly mechanism during straining that gives rise to the actuation properties and the structural changes that occur during contraction.