Accession Number : AD1029113

Title :   Encoding Gaussian Curvature in Glassy and Elastomeric Liquid Crystal Solids (Postprint)

Descriptive Note : Journal Article

Corporate Author : University of Cambridge Cambridge United Kingdom

Personal Author(s) : Mostajeran,Cyrus ; Warner,Mark ; Ware,Taylor H ; White,Timothy J

Full Text :

Report Date : 04 May 2016

Pagination or Media Count : 19

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.

Descriptors :   elastomers , curvature , deformation , liquid crystals

Distribution Statement : APPROVED FOR PUBLIC RELEASE