KES4-0058
Exploiting assemblies of liquid crystal oligomers for emergent shape, phase, and function
Topic
S4. Colloids, Interfaces, and Molecular Assemblies for Functional Soft Materials
When and Where
Sep 29, 2026
11:40 - 12:05
Room 106
Session Chairs
Chan-Jin KIM
Presenter(s)
Shu Yang (University of Pennsylvania)
Co-Author(s)
Abstract
Liquid crystal elastomers (LCEs) are a unique class of adaptive materials whose actuation arises from the coupling between mesogenic order and polymer elasticity. By engineering molecular alignment in films, filaments, particles, ribbons, and knots, LCEs can undergo diverse shape transformations through anisotropic contraction along the director and expansion perpendicular to it upon heating across the nematic–isotropic transition. However, actuation in conventional nematic LCEs is spontaneous and fully reversible, limiting their ability to retain programmed shapes without continuous external stimuli.
In this talk, I will demonstrate how molecular assembly and chain-length heterogeneity, often regarded as a defect, in liquid crystal oligomers (LCOs) can be leveraged to create responsive soft materials with unprecedented shape and phase behaviors. First, I will present examples of dramatic and reversible transformations from spherical LCO droplets to a rich spectrum of non-spherical morphologies upon cooling from the isotropic to the nematic phase. Remarkably, molecular heterogeneity drives and stabilizes these transitions while generating unique internal textures and topological structures. I will then show how we exploit a molecular design strategy by leveraging chain‑length polydispersity and a smectic solvent to stabilize the formation of layered smectic stacks during extrusion. The resulting LCEs exhibit programmable contraction or expansion within a single material system and possess robust, reprogrammable shape-memory behavior, enabling both preprogrammed and reprogrammable shape morphing beyond the capabilities of conventional nematic LCEs.
Together, these examples highlight how molecular assembly, phase behavior, and heterogeneity in chain length can be harnessed to create adaptive soft matter with programmable shape, memory, and reconfigurable function across multiple length scales.
In this talk, I will demonstrate how molecular assembly and chain-length heterogeneity, often regarded as a defect, in liquid crystal oligomers (LCOs) can be leveraged to create responsive soft materials with unprecedented shape and phase behaviors. First, I will present examples of dramatic and reversible transformations from spherical LCO droplets to a rich spectrum of non-spherical morphologies upon cooling from the isotropic to the nematic phase. Remarkably, molecular heterogeneity drives and stabilizes these transitions while generating unique internal textures and topological structures. I will then show how we exploit a molecular design strategy by leveraging chain‑length polydispersity and a smectic solvent to stabilize the formation of layered smectic stacks during extrusion. The resulting LCEs exhibit programmable contraction or expansion within a single material system and possess robust, reprogrammable shape-memory behavior, enabling both preprogrammed and reprogrammable shape morphing beyond the capabilities of conventional nematic LCEs.
Together, these examples highlight how molecular assembly, phase behavior, and heterogeneity in chain length can be harnessed to create adaptive soft matter with programmable shape, memory, and reconfigurable function across multiple length scales.
