Liquid crystal material is an alignment controllable substance due to its electromagnetic anisotropy. Azobenzene-functionalized liquid crystal polymers can perform various actuation modes such as bending, twisting, oscillating and folding upon exposure to actinic light. Recent studies have demonstrated perpetual photomotility toward soft robotics applications. In particular, helical liquid crystal soft robots have achieved rapid photomotility by employing rolling resistance. In this work, we varied the spacer length of the azobenzene-derived molecular machine ranging from 2-8 in order to optimize crosslink density at minimized dangling chains for effective stress transfer and photomotility. Photoactive molecular machines were self-assembled along with liquid crystal monomers with twisted nematic boundary conditions followed by photo polymerization in nematic phase. Remarkably, molecularly engineered soft robots demonstrated high mechanical stiffness but rapid photomotility with a large helical diameter, resulting in successful climbing of stairs.

Molecularly engineered photomotility of untethered soft robots

2019 Fall National Meeting

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