Monday  |  Salon 11  |  04:30 PM–04:50 PM

#15977, Experimental Characterization and Constitutive Modeling of Highly Deformable, Environmentally Responsive, Polyelectrolytes

Polymers with covalently incorporated ionic charge (polyelectrolytes) are a class of soft materials with extensive tunability of their mechanical properties and responsivity to stimuli such as electrical fields, pH, and relative humidity. Here, we will present a combined experimental and modeling study of bulk materials formed from polyelectrolyte complexes. Specifically, these complexes consist of polyanionic and polycationic acrylate copolymers mixed together and solvent cast. The presence of ionic interactions among polymer chains, and absence of covalent crosslinking, leads to polymers that can deform more than 40 times their initial length with nearly full recovery. Thanks to the versatility of the acrylate chemistry, the mechanical properties of our elastomers can be tuned by simply switching to a different neutral monomer, adjusting the percentage of the ionic components, changing environmental humidity, adding salts, or including only the polyanionic and polycationic components. The dependence on these design and environmental parameters was studied primarily through uniaxial tensile testing including strain rate dependence, cyclic loading, varied recovery time, and self-healing tests. A micromechanically-inspired constitutive model was developed in parallel with the experimental portion of the work. This model helps to quantify how aspects of the polymer design influence the governing mechanisms of the stress-strain response.

Meredith Silberstein   Cornell University
Hongyi Cai   Cornell University
Zhongtong Wang   Cornell University