Actuation of cylindrical nematic elastomer balloons

TL;DR

This paper explores the actuation of cylindrical nematic elastomer shells, demonstrating their potential as high-ejection-fraction pumps through large volume changes driven by temperature-induced deformation.

Contribution

It introduces a theoretical analysis of cylindrical nematic elastomer shells under pressure, highlighting a novel actuation mode involving large deformation and volume change.

Findings

Cylindrical shells can undergo significant volume change with temperature.

Proposed application as high-ejection-fraction pumps.

Theoretical model predicts large deformation behavior.

Abstract

Nematic elastomers are programmable soft materials that display large, reversible and predictable deformation under an external stimulus such as a change in temperature or light. While much of the work in the field has focused on actuation from flat sheets, recent advances in 3D printing and other methods of directed synthesis have motivated the study of actuation of curved shells. Snap-through buckling has been a topic of particular interest. In this work, we present theoretical calculations to motivate another mode of actuation that combines programmable soft materials as well as instabilities associated with large deformation. Specifically, we analyze the deformation of a cylindrical shell of a patterned nematic elastomer under pressure, show that it can undergo an enormous change of volume with changing temperature and suggest its application as a pump with extremely high ejection fraction.