title: Dynamic pattern of wrinkles in a dielectric elastomer.
abstract: A membrane of a dielectric elastomer may undergo electromechanical phase transition from the flat to wrinkled state, when the applied voltage reaches a critical value. The wrinkled region is observed to expand at the expense of the flat region during the phase transition. In this paper, we report on a dynamic pattern of wrinkles in a circular membrane of a dielectric elastomer. During phase transition, both the flat and wrinkled regions move interchangeably in the membrane. The radial prestretch is found to significantly affect electromechanical phase transition. For example, a membrane with a small prestretch can exhibit a dynamic pattern of wrinkles, which is essentially related to snap-through instability. However, a membrane with a large prestretch undergoes continuous phase transition, without exhibiting a dynamic pattern. An analytical model is developed to interpret these experimental phenomena. Finite element simulations are performed to predict the wrinkle morphology, especially the coexistence of flat and wrinkled regions. Both the theoretical calculations and finite element simulations are qualitatively consistent with the experiments. Additionally, we observe another type of electromechanical behavior involving a dynamic pattern of wrinkles with different wavelengths. The membrane first undergoes continuous transition from the flat to wrinkled state, followed by discontinuous transition from one wrinkled state to another. These results may inspire new applications for dielectric elastomers such as on-demand patterning of wrinkles for microfluidics and stretchable electronics.
authors.affiliation: Department of Mechanical Engineering, National University of Singapore, 9 Engineering Drive 1, Singapore 117576. mpezhuj@nus.edu.sg.
authors.forename: Hareesh
authors.initials: H
authors.lastname: Godaba
authors.affiliation: Institute of High Performance Computing, 1 Fusionopolis Way, #16-16 Connexis, Singapore 138632.
authors.forename: Zhi-Qian
authors.initials: ZQ
authors.lastname: Zhang
authors.affiliation: Department of Mechanical Engineering, National University of Singapore, 9 Engineering Drive 1, Singapore 117576. mpezhuj@nus.edu.sg.
authors.forename: Ujjaval
authors.initials: U
authors.lastname: Gupta
authors.affiliation: Institute of High Performance Computing, 1 Fusionopolis Way, #16-16 Connexis, Singapore 138632.
authors.forename: Choon
authors.initials: C
authors.lastname: Chiang Foo
authors.affiliation: Department of Mechanical Engineering, National University of Singapore, 9 Engineering Drive 1, Singapore 117576. mpezhuj@nus.edu.sg.
authors.forename: Jian
authors.identifier: http://orcid.org/0000-0001-8765-6026
authors.initials: J
authors.lastname: Zhu