Issue 6, 2021

Thermomechanically active electrodes power work-dense soft actuators

Abstract

The effect of chain extender structure and composition on the thermomechanical properties of liquid crystal elastomers (LCE) synthesized using thiol–acrylate Michael addition is presented. The intrinsic molecular stiffness of the thiol chain extender and its relative molar ratio to acrylate-based host mesogens determine the magnitudes of the thermomechanical strains, temperatures at which they are realized and the mechanical work-content. A non-linear structure–property relationship emerges, wherein higher concentrations of flexible extenders first magnify the thermomechanical sensitivity, but a continued increase leads to weaker actuation. Understanding this interplay leads to a composite material platform, enabling a peak specific work production of ∼2 J kg−1 using ∼115 mW of electrical power supplied at 2 V. Composites of LCE with eGaIn liquid metal (LM) are prepared, which act as heaters, while being capable of actuation themselves. The thermomechanically active electrodes convert the electrical power into Joule heat, which they efficiently couple with the neat LCE to which they are bound. This system harnesses the nascent responsiveness of the LCE using electrodes that work with them, instead of fighting against them (or passively standing in the way). Specific work generated increases when subjected to increasing levels of load, reaching a peak at loads ∼260× the actuator weight. These ideas are extended to tri-layered actuators, where LCE films with orthogonal molecular orientations sandwich LCE–LM composite heaters. Torsional actuation modes are harnessed to twist under load.

Graphical abstract: Thermomechanically active electrodes power work-dense soft actuators

Article information

Article type
Paper
Submitted
31 Jul 2020
Accepted
28 Nov 2020
First published
08 Dec 2020

Soft Matter, 2021,17, 1521-1529

Author version available

Thermomechanically active electrodes power work-dense soft actuators

A. Martinez, A. Clement, J. Gao, J. Kocherzat, M. Tabrizi and M. R. Shankar, Soft Matter, 2021, 17, 1521 DOI: 10.1039/D0SM01399D

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements