title: Copper-Coated Liquid-Crystalline Elastomer via Bioinspired Polydopamine Adhesion and Electroless Deposition.
abstract: This study explores the functionalization of main-chain nematic elastomers with a conductive metallic surface layer using a polydopamine binder. Using a two-stage thiol-acrylate reaction, a programmed monodomain is achieved for thermoreversible actuation. A copper layer (≈155 nm) is deposited onto polymer samples using electroless deposition while the samples are in their elongated nematic state. Samples undergo 42% contraction when heated above the isotropic transition temperature. During the thermal cycle, buckling of the copper layer is seen in the direction perpendicular to contraction; however, transverse cracking occurs due to the large Poisson effect experienced during actuation. As a result, the electrical conductivity of the layer reduced quickly as a function of thermal cycling. However, samples do not show signs of delamination after 25 thermal cycles. These results demonstrate the ability to explore multifunctional liquid-crystalline composites using relatively facile synthesis, adhesion, and deposition techniques.
authors.affiliation: Department of Mechanical Engineering, University of Wyoming, Laramie, WY 82071, USA.
authors.forename: Carl P
authors.initials: CP
authors.lastname: Frick
authors.affiliation: Department of Mechanical Engineering, University of Wyoming, Laramie, WY 82071, USA.
authors.forename: Daniel R
authors.initials: DR
authors.lastname: Merkel
authors.affiliation: Department of Mechanical Engineering, University of Wyoming, Laramie, WY 82071, USA.
authors.forename: Christopher M
authors.initials: CM
authors.lastname: Laursen
authors.affiliation: Department of Mechanical Engineering, University of Wyoming, Laramie, WY 82071, USA.
authors.forename: Stephan A
authors.initials: SA
authors.lastname: Brinckmann
authors.affiliation: Department of Mechanical Engineering, University of Colorado Denver, Denver, CO 80217, USA.
authors.forename: Christopher M
authors.initials: CM
authors.lastname: Yakacki
mesh_terms: D020099:Coated Materials, Biocompatible / Q000138:chemical synthesis / Q000737:chemistry*; D003300:Copper / Q000737:chemistry*; D020724:Elastomers / Q000737:chemistry*; D004553:Electric Conductivity; D007211:Indoles / Q000737:chemistry*; D050866:Liquid Crystals / Q000737:chemistry*; D010316:Particle Size; D011108:Polymers / Q000737:chemistry*; D013499:Surface Properties; D013696:Temperature
chemical_list: D020099:Coated Materials, Biocompatible; D020724:Elastomers; D007211:Indoles; D011108:Polymers; C568283:polydopamine; D003300:Copper
keywords: actuation; electroless deposition; liquid crystalline elastomers; polydopamine adhesion