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Encoding Gaussian curvature in glassy and elastomeric liquid crystal solids.

Published version
Peer-reviewed

Repository DOI


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Authors

Mostajeran, Cyrus 
Ware, Taylor H 
White, Timothy J 

Abstract

We describe shape transitions of thin, solid nematic sheets with smooth, preprogrammed, in-plane director fields patterned across the surface causing spatially inhomogeneous local deformations. A metric description of the local deformations is used to study the intrinsic geometry of the resulting surfaces upon exposure to stimuli such as light and heat. We highlight specific patterns that encode constant Gaussian curvature of prescribed sign and magnitude. We present the first experimental results for such programmed solids, and they qualitatively support theory for both positive and negative Gaussian curvature morphing from flat sheets on stimulation by light or heat. We review logarithmic spiral patterns that generate cone/anti-cone surfaces, and introduce spiral director fields that encode non-localized positive and negative Gaussian curvature on punctured discs, including spherical caps and spherical spindles. Conditions are derived where these cap-like, photomechanically responsive regions can be anchored in inert substrates by designing solutions that ensure compatibility with the geometric constraints imposed by the surrounding media. This integration of such materials is a precondition for their exploitation in new devices. Finally, we consider the radial extension of such director fields to larger sheets using nematic textures defined on annular domains.

Description

Keywords

curvature, elastomers, nematic, solids

Journal Title

Proc Math Phys Eng Sci

Conference Name

Journal ISSN

1364-5021
1471-2946

Volume Title

472

Publisher

The Royal Society
Sponsorship
Engineering and Physical Sciences Research Council (EP/E051251/1)
Engineering and Physical Sciences Research Council (EP/J017639/1)
EPSRC (1355845)
C. Mostajeran is supported by the Engineering and Physical Sciences Research Council (EPSRC) of the United Kingdom. T. J. White and T. H. Ware acknowledge financial support from the Materials and Manufacturing Directorate of the Air Force Research Laboratory and the Air Force Office of Scientific Research.