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Electrical Control of Shape in Voxelated Liquid Crystalline Polymer Nanocomposites

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journal contribution
posted on 14.12.2017, 00:00 by Tyler Guin, Benjamin A. Kowalski, Rahul Rao, Anesia D. Auguste, Christopher A. Grabowski, Pamela F. Lloyd, Vincent P. Tondiglia, Benji Maruyama, Richard A. Vaia, Timothy J. White
Liquid crystal elastomers (LCEs) exhibit anisotropic mechanical, thermal, and optical properties. The director orientation within an LCE can be spatially localized into voxels [three-dimensional (3-D) volume elements] via photoalignment surfaces. Here, we prepare nanocomposites in which both the orientation of the LCE and single-walled carbon nanotube (SWNT) are locally and arbitrarily oriented in discrete voxels. The addition of SWNTs increases the stiffness of the LCE in the orientation direction, yielding a material with a 5:1 directional modulus contrast. The inclusion of SWNT modifies the thermomechanical response and, most notably, is shown to enable distinctive electromechanical deformation of the nanocomposite. Specifically, the incorporation of SWNTs sensitizes the LCE to a dc field, enabling uniaxial electrostriction along the orientation direction. We demonstrate that localized orientation of the LCE and SWNT allows complex 3-D shape transformations to be electrically triggered. Initial experiments indicate that the SWNT–polymer interfaces play a crucial role in enabling the electrostriction reported herein.