397607 Shape Actuation of Dual-Cured Networks

Monday, November 17, 2014
Galleria Exhibit Hall (Hilton Atlanta)
Jisu Jiang1, Yuan Meng2 and Mitchell Anthamatten1, (1)Chemical Engineering, University of Rochester, Rochester, NY, (2)Chemical Engineering, UNniversity of Rochester, Rochester, NY

Conventional two-way shape-memory polymers switch between two shapes in response to temperature in the presence of an external load. In this work, we demonstrate a single phase, two-way shape actuator which is thermal-responsive without an external load. Double networks were formed by Thiol-acrylate Michael addition, followed by additional chemical cross-linking using UV irradiation under pre-strained conditions. Prepared samples exhibit contractile forces along the pre-strained direction upon melting of crystalline domains due to entropic elasticity of the first network.  Samples reversibly elongate, upon cooling, due to internal stress-induced crystallization along the same direction. The degree of orientation and reversible crystallization was further investigated using a combination of X-ray diffraction and calorimetry.  Shape actuation was studied at various pre-strained conditions. Under optimized conditions, reversible actuation of around 15% strain can be reproducibly achieved and cycled many times with nearly uniform actuation.

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