Egunov A I, Korvink J G, Luchnikov V A
Institut de Science des Matériaux de Mulhouse, UMR 7361 CNRS-UHA, 15 rue Jean Starcky, 68057 Mulhouse, France.
Karlsruhe Institute of Technology, Institute of Microstructure Technology, Hermann von Helmholtz Platz 1, 76344 Eggenstein-Leopoldshafen, Germany.
Soft Matter. 2016 Jan 7;12(1):45-52. doi: 10.1039/c5sm01139f.
Elastomer polydimethylsiloxane (PDMS) films with embedded in-plane gradient stress are created by making PDMS/(PDMS + silicone oil) crosslinked bilayers and extracting the oil in a suitable organic solvent bath. The collapse of the elastomer after oil extraction generates differential stress in the films that is manifested through their out-of-plane deformation. The curvature κ of narrow stripes of the bilayer, which is composed of layers of approximately equal thicknesses and elasticity moduli, is satisfactorily described by the simple relationship κ = 1.5δH(-1), where δ is the mechanical strain, and H is the total thickness of the bilayer. Curvature mapping of triangular PDMS plates reveals the existence of spherical and cylindrical types of deformation at different locations of the plates. Various 3D-shaped objects can be formed by the self-folding of appropriately designed 2D patterns that are cut from the films, or by nonuniform distribution of the collapsing layer. Thin PDMS bilayers with embedded stress roll up into microtubes of almost perfect cylindrical shape when released in a controlled manner from a substrate.
通过制备聚二甲基硅氧烷（PDMS）/（PDMS + 硅油）交联双层膜，并在合适的有机溶剂浴中萃取硅油，可制得具有面内梯度应力的弹性体聚二甲基硅氧烷（PDMS）薄膜。萃取硅油后弹性体的塌陷会在薄膜中产生差异应力，这通过其面外变形表现出来。由厚度和弹性模量大致相等的层组成的双层窄条的曲率κ，可由简单关系κ = 1.5δH⁻¹令人满意地描述，其中δ是机械应变，H是双层的总厚度。三角形PDMS板的曲率映射揭示了板不同位置存在球形和柱形变形类型。各种三维形状的物体可通过从薄膜上切割出的适当设计的二维图案的自折叠，或通过塌陷层的不均匀分布形成。当以可控方式从基板释放时，嵌入应力的薄PDMS双层会卷成几乎完美圆柱形的微管。
