(502c) Multi-Stimuli Responsive Self-Folding Origami with Shape Memory Polymer Composites

Self-folding origami utilizes smart materials, such as shape memory polymers (SMPs), to convert initially flat sheets into three-dimensional (3D) structures in response to an external stimulus. A variety of stimuli are available for actuating SMP sheets, including convective heating, light absorption, microwaves, and electric Joule heating. The ability of a polymer to respond to multiple stimuli increases the utility of self-folding origami as a fabrication technique, including the ability for remote deployment and control of heating and folding rates. However, most studies of self-folding origami focus on the folding behavior of SMP sheets in response to a single stimulus. Herein, we investigate SMP sheets capable of responding to multiple stimuli, and the interaction of various stimuli to control the folding response. We use sheets of commodity polymers that are prestrained in our lab using a lab scale pre-straining device. We perform an initial characterization of the shape memory response of these materials using uniform shape recovery tests, and then we evaluate the ability of the sheets to respond to multiple stimuli. This portion of the research begins with an investigation of polymer sheets patterned with ink, which is capable of absorbing thermal energy from an infrared light. Simultaneously, the sheets incorporate conductive materials which heat when an electric current is applied. The ability to actuate the shape memory effect using multiple stimuli will accelerate the integration of self-folding origami into practical systems for soft robotics, deployable structures, and aerospace applications.