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Register a new userBending and wrinkling as competing relaxation pathways for strained free-hanging films
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An equilibrium phase diagram for the shape of compressively strained free-hanging films is developed by total strain energy minimization. For small strain gradients {Delta}{epsilon}, the film wrinkles, while for sufficiently large {Delta}{epsilon}, a phase transition from wrinkling to bending occurs. We consider competing relaxation mechanisms for free-hanging films, which have rolled up into tube structures, and we provide an upper limit for the maximum achievable number of tube rotations.
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We investigate the relaxation of rectangular wrinkled thin films intrinsically containing an initial strain gradient. A preferential rolling direction, depending on wrinkle geometry and strain gradient, is theoretically predicted and experimentally verified. In contrast to typical rolled-up nanomembranes, which bend perpendicular to the longer edge of rectangular patterns, we find a regime where rolling parallel to the long edge of the wrinkled film is favorable. A non-uniform radius of the rolled-up film is well reproduced by elasticity theory and simulations of the film relaxation using a finite element method.
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