(266d) Photodirected Wrinkle Formation On a Thiol-Ene Elastomer
Wrinkles are a cost-efficient method to produced surface topography, and have a wide range of potential applications including antifouling coatings1-3, adhesives4, and microarray lenses with tunable focal lengths.5 However, the precise control over wrinkle confinement and orientation necessary to engineering textured surfaces remains a challenge.
Photopolymerization is an attractive method to spatiotemporally direct wrinkle formation. Using acrylate-rich thiol-ene elastomers, embedded with a photoinitiator and photoabsorber, we can irradiate strained elastomers with UV light to generate wrinkles in as little as five seconds. While the photointiator aids in radical polymerization of the acrylates, the photoabsorber confines the UV light to a thin skin layer, creating the necessary conditions for wrinkle formation upon release of the strain. In conjunction with photomasked UV light, these wrinkles are confined and oriented, leading limitless complex patterns of multiple distinct wavelengths and the formation of gradients containing a continuum of length scales. Moreover, with a photoorthogonal photoinitator, these wrinkles can subsequently be locked in through additional bulk radical polymerization. With the wide array of thiol and ene monomers, photoiniators, photomasks and stoichiometric control, we present an alternative approach to wrinkle formation that is rapid, facile, and highly versatile, further enabling the a priori design and engineering of textured surfaces
(1) Efimenko, K., Finlay, J., Callow, M. E., Callow, J. A. and Genzer, J. ACS Appl. Mater. Interfaces 2009, 1, 1031-1040
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(3) Schumacher, J. F., Carman, M. L., Estes, T. G., Feinberg, A. W., Wilson, L. H., Callow, M. E., Callow, J. A., Finlay, J. A. and Brennan, A. B. Biofouling 2007, 23, 55-62
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(5) Chandra, D., Yang, S. and Lin, P.-C. Appl. Phys. Lett. 2007, 91,