External compression-induced fracture patterning on the surface of poly(dimethylsiloxane) cubes and microspheres.
This article describes a method for creating submicrometer surface patterns on cubes and microspheres. In this method, PDMS cubes and microspheres are exposed to oxygen plasma, which creates a very thin, hard, surface-modified layer on a compliant substrate. These are then compressed, causing the layer to crack in patterns dictated by the distribution of tensile stresses in the surface layer. Cracks with submicrometer widths were generated on 1 cm3 cubes and 800-microm-diameter microspheres, and the resulting crack patterns were observed. Finite-element simulations of the tensile stress distributions reveal that the fracture patterns arise from different mechanisms in the cubes and spheres. In particular, pattern formation is associated with frictional contact in the cubes but not in the microspheres, where geometrical effects associated with changes in the cross-sectional area along the axis lead to the generation of tensile stress. These observations and analyses provide a foundation on which to predict and guide crack pattern formation on a wide variety of small 3D objects. In anticipation of future applications in materials science and biology, we demonstrate the selective deposition of compounds into the cracks to make them functionally differentiable from the rest of the surface.
Department of Biomedical Engineering, University of Michigan, Ann Arbor, Michigan 48109, USA.
Tomoyuki
T
Uchida
K L
KL
Mills
Chuan-Hsien
CH
Kuo
Whijae
W
Roh
Yi-Chung
YC
Tung
Amanda L
AL
Garner
Kazunori
K
Koide
M D
MD
Thouless
Shuichi
S
Takayama
D000097:Acetonitriles / Q000737:chemistry; D000588:Amines / Q000737:chemistry; D002855:Chromatography, Thin Layer / Q000379:methods; D003102:Colloids / Q000737:chemistry; D019245:Compressive Strength; D004058:Diffusion; D004129:Dimethylpolysiloxanes / Q000737:chemistry*; D007477:Ions; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D008863:Microspheres; D008956:Models, Chemical; D011437:Propylamines; D012821:Silanes / Q000737:chemistry; D012822:Silicon Dioxide / Q000737:chemistry*; D013499:Surface Properties
D000097:Acetonitriles; D000588:Amines; D003102:Colloids; D004129:Dimethylpolysiloxanes; D007477:Ions; D011437:Propylamines; D012821:Silanes; C013830:baysilon; D012822:Silicon Dioxide; C477625:amino-propyl-triethoxysilane; C032159:acetonitrile