Threading the Spindle: A Geometric Study of Chiral Liquid Crystal Polymer Microparticles

Polymeric particles are strong candidates for designing artificial materials capable of emulating the complex twisting-based functionality observed in biological systems. In this study we investigate the swelling behavior of chiral twisted spindle-shaped polymer microparticles, which are formed due to the anisotropic contraction of spherical bipolar polymer liquid crystalline microparticles during deswelling. We observe a relationship between the aspect ratio of the spindle shape and the corresponding twist angle of the polymer at the surface. We find that there are two regions in the deswelling process: shrinking without twisting followed by shrinking due to twisting. We propose a geometric model to interpret these two behaviors as well as describing the observed spiral patterns on the surface.

H. S. Ansell, D. S. Kim, R. D. Kamien, E. Katifori, and T. Lopez-Leon, Phys. Rev. Lett. 123, 157801 (2019)