Characterization of micro-scale creep deformation of an electro-active paper actuator

The creep deformation process of an electro-active paper (EAPap) actuator was investigated by adapting stepwise dead-weight loading. To understand the deformation mechanism of the EAPap film, including morphological and structural changes, various loading conditions below yield strength were applied to cellophane EAPap. From the structural observation, micro-dimples and micro-cracks were detected at applied load lower than 10% of yield strength, while they were not found in higher load conditions. It is hypothesized that only short and random fibers in the amorphous region may respond to the applied stress at the low loading condition, not the fibers in the crystalline area. As a result, deformation energy at the localized spot accumulated and created micro-defects at the surface. Meanwhile, fibers in the crystalline region may sustain most of the loads as creep load increases to a high level. Molecular chains in the fiber may rotate and elongate with high load. Elongated fibers were observed only at a high level of load. From the structural change as a function of applied load, a peak shift of crystal orientation was observed only in high load conditions by wide angle x-ray measurement. This may confirm that creep deformation could give rise to structure changes in EAPap