Electroplastic elastomer hydrogels (EPEHs) are a class of materials whose mechanical properties can be switched reversibly between hard and soft states with the application of an electric potential. Previously, we reported on our first-generation EPEH which utilized the Fe(II)/Fe(III) redox couple to reversibly tune mechanical properties by electrochemically switching iron oxidation states between the strongly-crosslinking Fe(III) and weakly-crosslinking Fe(II). In an effort to better understand the crosslinking mechanism and conversion between hard and soft states, quantitative analysis of iron and carboxylate content was performed. Mechanical properties measurements of the EPEHs as a function of the Fe(II)/Fe(III) ratio were determined. Magnetic susceptibility measurements were consistent with the formation of iron clusters within the hydrogel. Potentiometric titrations provided additional information about iron coordination. Incorporation of graphene oxide (GO) as a filler enhanced the mechanical properties of the material and decreased the conversion time between hard and soft states.

Physical studies on stimuli-responsive iron-based hydrogels

248th National Meeting (2014)

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