Microstructured Photopolymerization of Liquid Crystalline Elastomers in Oxygen‐Rich Environments
Abstract
Liquid crystal elastomers (LCEs) are soft materials that undergo large anisotropic shape change in response to stimuli. Rational organization of the local director field can impart spatial control of the strain profile, enabling stretch‐based deformation capable of nearly 20 J kg−1 of output force. LCEs are increasingly being considered in end‐use applications in robotics, therapeutics, and optics. Here, a new synthetic approach is introduced to prepare LCEs composed of main chain mesogens via the cationic photopolymerization of the epoxy liquid crystal monomer (LCM). This examination details the optical, mechanical, and thermal properties of epoxide‐based LCEs as a function of spacer length (3, 6, or 11 carbons). The oxygen insensitivity of the cationic photopolymerization of these monomers makes this approach particularly attractive for implementation with emerging additive manufacturing techniques. This contribution focuses on microstructuring LCEs via 2‐photon direct laser writing (2P‐DLW). A custom heated cell facilitated 2P‐DLW of the aligned LCE epoxy resin melts to fabricate diverse geometric arrays. Enabled by the orthogonality of the reaction chemistry, hybrid and microstructured material compositions are prepared via the encapsulation of LCE epoxy micropatterns with free‐radical polymerization of acrylate‐based LCEs. The distinct thermomechanical response of the hybridized and microstructured LCE composites enables local and spatially controlled actuation.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Jul 17, 2019
- Source ID
- 10.1002/adfm.201903761
Entities
People
- Anesia D. Auguste
- Brian R. Donovan
- Brody N. Bagnall
- Chance M. Baxter
- Hayden E. Fowler
- John D. Berrigan
- Joselle M McCracken
- Nicholas P Godman
- Timothy White
- Valentina Matavulj
- Vincent P. Tondiglia
Organizations
- Air Force Office of Scientific Research
- Air Force Research Laboratory
- Azimuth Corporation
- National Research Council
- United States Air Force Academy
- University of Colorado Boulder