CAREER: Electroactive Graphene-Polymer System with Extreme Actuation and Tunable Properties

The research objective of this Faculty Early Career Development (CAREER) Program award is to understand and exploit the large deformation, instabilities, and microstructure evolution of electroactive graphene-polymer systems (eGPS) to achieve extremely high actuation stress and strain, along with other novel properties such as superhydrophobicity and tunable wettability. Subject to voltages, existing polymers can reach relatively high levels of either stress or strain, but not both. This imbalance in actuation stress and strain greatly limits the energy density of these polymers and hampers their promising applications. The proposed eGPS innovatively laminates films of polymer blends and large-area graphene with hierarchical patterns. The polymer blends integrate merits of different polymers, while the patterned graphene acts as lightweight transparent electrodes with novel tunable properties. The proposed study will take an integrated experimental and theoretical approach. A multi-field microscopic system invented by the PI will be used to explore electromechanical properties and instabilities of eGPS, and a multi-scale theoretical model will be developed to quantitatively guide the design of new materials and structures.

Electroactive graphene-polymer systems represent a new type of soft active material with multiple performance parameters that are superior to natural muscles. These so-called artificial muscles are enabling diverse technologies ranging from robotics and drug delivery to energy harvesting and storage. In particular, artificial muscles promise to greatly improve the quality of life for millions of disabled people by providing affordable devices such as lightweight anthropomorphic prostheses and full-page Braille displays. The broad impact of new artificial muscles is potentially analogous to the impact of piezoelectric ceramics on the global society in the twentieth century. The integrated educational objectives of the project include integration of soft-active-material design into the Duke engineering curriculum, a Research Experience for Teachers program on artificial muscles, and a K-12 program at the Durham Museum of Life and Science. In addition, students from underrepresented groups will be actively engaged in the project through the close interactions between Duke University and North Carolina Central University.