Electromechanics in soft active materials: statistical mechanics analysis and multiscale experiments

A short description of the project in layman’s terms BSF application 2018183 Electromechanics in soft active materials: statistical mechanics analysis and multiscale experiments Kaushik Dayal, Carnegie-Mellon Univ., U.S.A.

Carmel Majidi, Carnegie-Mellon Univ., U.S.A.

Gal deBotton, Ben-Gurion Univ., Israel Exciting materials that deform and move in response to electrical, magnetic and other non- mechanical stimuli such as light and sound are on the verge of becoming part of our daily lives. The class of electroactive polymers (EAP) that change their size and shape in response to electrostatic excitation is one of the most promising classes in this group. These readily excited and controlled, lightweight, fast response and durable materials can be incorporated in spacecrafts, miniature robotic and biomedical devices and even in toys and apparel products. The electromechanical coupling is a key in the success of these materials - roughly speaking - it is the ratio of the mechanical outcome to the electrical input. In presently available EAPs this ratio is quite low, and thousands of Volts are required to obtain a meaningful deformation. Our proposed research deals precisely with this issue — both theoretically and experimentally.

It has been shown recently by one of the partners that, in theory, with an appropriate microstructure this electromechanical coupling can be tremendously enhanced. Motivated by these findings, in this work we wish to explore and reveal the origins for the electromechanical coupling at the molecular network of these polymers. To this end we combine the expertise of one of the American partners in molecular to continuum analyses and the knowledge of the Israeli partner in soft and deformable polymers. Their joint theoretical analysis will be compared and validated against the experimental findings of the second American partner. Our joint goal is to identify those microstructural parameters that have the greatest impact on the electromechanical response of polymers. Moreover, we wish to understand how the polymer chains should be manipulated in order to improve this coupling. The results of our study will enable to manufacture highly sensitive EAPs that, in response to a few tenth of Volts, change their shape much like biological muscles.