Pixelated Polymers: Directing the Self-Assembly of Liquid Crystalline Elastomers
Brian Donovan, Air Force Research Laboratory
Abstract: Liquid crystalline (LC) materials are pervasive in modern society. Owing to their exceptional characteristics in polymeric form, LC materials have been widely utilized in high performance applications. A specific class of liquid crystalline polymeric materials, referred to as liquid crystalline elastomers, have exceptional promise as artificial muscles owing to the unique assimilation of anisotropy and elasticity. Subsequent experimental studies have confirmed the salient features of these materials, with respect to other forms of stimuli-responsive soft matter, include actuation cycles of up to 400% as well “soft elasticity” (stretch at minimal stress). This presentation will summarize recent efforts at AFRL to develop materials chemistry amenable to directed self-assembly and elastic behavior. Due to the inherent temperature sensitivity of these materials, employing photoinitiated polymerization is advantageous. Our activities at AFRL have developed novel, photopolymerizable formulations that are conducive to surface alignment. Enabled by these chemistries and processing methods, we have prepared homogeneous (lacking material/material interfaces) liquid crystal elastomers with distinctive actuation and mechanical properties. Relevance of this work to implementations in aerospace and commercial applications will be discussed.