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 was achieved for thermo-reversible actuation. A copper layer (∼155 nm) was deposited onto polymer samples using electroless deposition while the samples were in their elongated nematic state. Samples underwent 42% contraction when heated above the isotropic transition temperature. During the thermal cycle, buckling of the copper layer was seen in the direction perpendicular to contraction; however, transverse cracking occurred 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 did not show signs of delamination after 25 thermal cycles. These results demonstrate the ability to explore multi-functional liquid-crystalline composites using relatively facile synthesis, adhesion, and deposition techniques.

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The purpose of this study was to develop a degradable thermoset shape-memory polymer from poly(b-amino ester) (PBAE) networks. PBAE was chosen to be the crosslinker as it is biodegradable and has been projected as a potential material for biomedical applications. The low glass transition temperature of PBAE was increased to a biomedically relevant range using methyl methacrylate and methyl acrylate as the linear chain builders. The thermo-mechanical properties of the networks were tailored such that they exhibited onset of glass transition temperature in between the room temperature (22 C) and the body temperature (37 C). Free-strain recovery tests under heating and isothermal conditions were performed to quantify shape-memory behavior. Testing showed that sampled programmed at 10 C ini-tiated deformation recovery at a lower temperature and a faster rate as compared to programming at 60 C. Higher thermal conductivity of water enabled the samples to recover faster in water than in air. Samples with higher PBAE crosslinking densities exhibited higher normalized mass loss under regular and accelerated conditions. The amount of water absorption in the networks also increased with the crosslinker concentration independent of the testing conditions.

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