title: Topography-guided buckling of swollen polymer bilayer films into three-dimensional structures.
abstract: Thin films that exhibit spatially heterogeneous swelling often buckle into the third dimension to minimize stress. These effects, in turn, offer a promising strategy to fabricate complex three-dimensional structures from two-dimensional sheets. Here we employ surface topography as a new means to guide buckling of swollen polymer bilayer films and thereby control the morphology of resulting three-dimensional objects. Topographic patterns are created on poly(dimethylsiloxane) (PDMS) films selectively coated with a thin layer of non-swelling parylene on different sides of the patterned films. After swelling in an organic solvent, various structures are formed, including half-pipes, helical tubules, and ribbons. We demonstrate these effects and introduce a simple geometric model that qualitatively captures the relationship between surface topography and the resulting swollen film morphologies. The model's limitations are also examined.
authors.affiliation: Department of Physics, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Republic of Korea. jjeong@unist.ac.kr.
authors.forename: Joonwoo
authors.initials: J
authors.lastname: Jeong
authors.forename: Yigil
authors.initials: Y
authors.lastname: Cho
authors.forename: Su Yeon
authors.initials: SY
authors.lastname: Lee
authors.forename: Xingting
authors.initials: X
authors.lastname: Gong
authors.forename: Randall D
authors.initials: RD
authors.lastname: Kamien
authors.forename: Shu
authors.initials: S
authors.lastname: Yang
authors.forename: A G
authors.initials: AG
authors.lastname: Yodh