Al Crosby, Professor and Head of the Polymer Science & Engineering Department, University of Massachusetts Amherst

"Power-dense, Regenerated, and Coordinated Soft Matter Movement"

Abstract:

Soft materials enable impressive feats of movement in nature, from power-dense, shell-smashing mantis shrimp to self-entangling plant tendrils. In engineered technologies, soft materials remain under-employed for creating movement; however, they offer key advantages for meeting the needs of new technologies, ranging from autonomous robots to self-weaving textiles. Here, we will present recent projects that address autonomous and control-enhanced movements, with a focus on the development of materials that can provide self-regenerating, coordinated responses. We first introduce materials science principles and lessons from organisms that use Latch-Mediated Spring Actuation (LaMSA) to achieve high power, impulsive movements by integrating actuators, elastic elements, and stability-mediating latches. We demonstrate how transient metastable deformations associated with swelling and deswelling of a polymer gel can be exploited to generate mechanical bi-stability, giving rise to multiple, self-repeating, snap-through movements. Second, we introduce polymer filaments that enable the integration of interfacial and poroelastic fields to create complex, mechanically-interlocked topologies. The combination of fields allows for spatiotemporal coordination of kinematic transformations to achieve linking. The realization of sub-micron mechanically interlocked structures will lead to advances in wireless communication, medical devices, and pathways for sustainable, circular materials engineering. Collectively, the strategies and results discussed here provide new insight into how polymer properties can combine with purposeful structural design to achieve complex tasks, which can be used in the development of microscale robots and adaptable materials.

Bio:

Alfred J. Crosby is Professor and Head of the Polymer Science & Engineering Department at the University of Massachusetts Amherst. He leads a research group focused on bioinspired materials mechanics, covering topics ranging from adhesion to complex assembly to high power actuation. Al received his B.S. in Civil Engineering and Applied Mechanics from the University of Virginia and his Ph.D. in Materials Science & Engineering from Northwestern University. He was an NRC Postdoctoral Fellow at NIST before joining UMass Amherst in 2002.  He has received numerous awards, including being a Fellow of the American Physical Society, the Royal Society of Chemistry, and the National Academy of Inventors, and his research has been covered extensively in the popular media. He serves on several advisory boards and is the Editor-in-Chief for the Royal Society of Chemistry journal Soft Matter.