Shape memory polymer composite structures with two-way shape memory effects

Shape memory polymers (SMPs) usually exhibit one-way shape memory effect. A simple and effective way to obtain two-way shape memory effect by SMP composite structures is proposed. The system consists of a SMP film with higher glass transition temperature T-g surrounded on another SMP cylindrical core with lower T-g. A special thermomechanical process is performed. During this process the mismatched deformation between the SMP film and cylindrical core intrigues the structure developing from smooth to buckled configuration, and then recovering its original smooth shape. In this study, we confirmed such two-way transition by the theoretical prediction and experimental observation. The means to produce two-way graded shape memory effect is also proposed. (C) 2012 Elsevier B.V. All rights reserved.