(391c) Electrochemical Jamming in Dense Suspensions: Training and Memory

Shear-induced jamming and its impact-induced solidification of dense suspensions are important behaviors that can allow access to stress mitigating functional response. We have designed suspensions particles whose crosslink density can be reversibly tuned in response to an external stimulus such as electric field. Upon exposure of a dense suspension of these particles to an electric field, a drastic change in mechanical properties, namely jamming and solidification, was observed. The degree of solidification can be controlled by repeatedly switching the field on and off. Furthermore, it was shown that the suspension is capable of forming a structural memory under oscillatory shear (“training”), and the yield strain of the suspension can be tailored depending on the training strain. The structural memory persists even after the external stimulus is removed. The trained suspension can unjam and lose its memory when the applied strain exceeds the training strain. Trainability of the suspension may enhance the impact-resisting functionality as various structural rigidities can be embedded in such suspensions.