Macromolecules, Vol.49, No.1, 134-140, 2016
Phase-Changing Bistable Electroactive Polymer Exhibiting Sharp Rigid-to-Rubbery Transition
A phase-changing polymer comprising stearyl acrylate and a long-chain urethane diacrylate was studied as a new bistable electroactive polymer. The abrupt and reversible phase transition of the crystalline aggregates of the stearyl moieties results in a rapid shift between the rigid and rubbery states of the polymers during temperature cycles. The transition temperature is tunable between 34-46 degrees C. A storage modulus change of 4000 fold can be obtained within a narrow temperature range of 10 degrees C. The polymer shows excellent shape memory properties with both fixation rate and recovery rate close to 100%. Diaphragm actuators based on the polymer thin films were electrically actuated up to 70% strain at 50 degrees C. The actuated shape can be "frozen" after the films were allowed to cool below the transition temperature. This rigid-to-rigid deformation is refreshable and repeatable via the rigid-to-rubbery transition and electrical actuation in the rubbery state.