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Theme 2 colloquium by Michael Lerch: 'Unusual Deformations of Liquid Crystalline Elastomer Microstructures' (Lecture)

Tuesday 12 January 2021Add to my calendar
from 16:00
dr. Michael Lerch (Harvard University, USA)

Michael LerchThe range of motion of arms or other appendages critically determines their usefulness for accomplishing tasks. While traditional engineering approaches are very successful for robotics arms at the macroscale, the reliance on hard materials, electronic circuitry, and multiple components severely limit robots at the microscale. Recent advances in controlling motion of soft materials, particularly through new fabrication strategies and borrowing concepts from supramolecular and systems chemistry, provide new solutions to microscale actuators with extended ranges of motion. Yet, compared to their natural counterparts such as flagella and cilia, which repeatedly switch and adjust their complex deformation trajectories, synthetic microactuators remain rather simplistic. In this presentation, I will discuss the design of novel optically active liquid crystalline elastomer microactuators capable of a range of (previously unachievable) deformation patterns. Reminiscent of biological cilia, the microstructures show non-reciprocal 'power-stroke'-type beating that can easily be programmed with regard to type, amplitude, and direction. I will explain how the sophisticated behavior of these structures can be evoked through a combination of localized excitation, propagation of light through the pillar, and symmetry breaking. Subsequently, I will discuss our recent work on how an in-depth understanding of structure-property relationships in liquid crystalline elastomers can be used to design de-novo deformation behaviors rooted fully in chemistry. This work offers a new approach to functional complexity in compositionally simple materials by careful design of liquid crystal phase-behavior and by leveraging processes beyond stimuli-responsive chemistry.

dr. Peter Korevaar & dr. Evan Spruijt