Unravelling humidity-gated, temperature responsive bilayer actuators

Rob C P Verpaalen; Anne E J Souren; Michael G Debije; Tom A P Engels; Cees W M Bastiaansen; Albertus P H J Schenning

doi:10.1039/d0sm00030b

Unravelling humidity-gated, temperature responsive bilayer actuators

Soft Matter. 2020 Mar 18;16(11):2753-2759. doi: 10.1039/d0sm00030b.

Authors

Rob C P Verpaalen¹, Anne E J Souren², Michael G Debije², Tom A P Engels³, Cees W M Bastiaansen⁴, Albertus P H J Schenning¹

Affiliations

¹ Laboratory of Stimuli-Responsive Functional Materials and Devices, Department of Chemical Engineering and Chemistry, Eindhoven University of Technology, P.O. Box 513, 5600 MB, Eindhoven, The Netherlands. a.p.h.j.schenning@tue.nl and Dutch Polymer Institute (DPI), P.O. Box 902, 5600 AX Eindhoven, The Netherlands.
² Laboratory of Stimuli-Responsive Functional Materials and Devices, Department of Chemical Engineering and Chemistry, Eindhoven University of Technology, P.O. Box 513, 5600 MB, Eindhoven, The Netherlands. a.p.h.j.schenning@tue.nl.
³ Department of Mechanical Engineering, Materials Technology Institute, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands and Dutch Polymer Institute (DPI), P.O. Box 902, 5600 AX Eindhoven, The Netherlands.
⁴ Laboratory of Stimuli-Responsive Functional Materials and Devices, Department of Chemical Engineering and Chemistry, Eindhoven University of Technology, P.O. Box 513, 5600 MB, Eindhoven, The Netherlands. a.p.h.j.schenning@tue.nl and Dutch Polymer Institute (DPI), P.O. Box 902, 5600 AX Eindhoven, The Netherlands and School of Engineering and Materials Science, Queen Mary University of London, Mile End Road, London E1 4NS, UK.

PMID: 32083272
DOI: 10.1039/d0sm00030b

Abstract

By spraying liquid crystal mixtures onto stretched polyamide 6 (PA6) substrates, dual-responsive heat/humidity bilayer actuators are generated. The oriented PA6 guides the self-organization of the liquid crystal monomers into well-aligned, anisotropic liquid crystal networks. The bilayer responds to changes in the environmental relative humidity, resulting in bending of the actuator with the liquid crystal network inside the curvature. In contrast, in conditions of constant high humidity (80%RH), increasing the temperature triggers the liquid crystal network coating to bend the bilayer in the opposing direction. The dual-responsivity to changes in environmental humidity and temperature is examined in detail and discussed theoretically to elucidate the humidity-gated, temperature responsive properties revealing guidelines for fabricating anisotropic bilayer actuators.