Ordering of Spontaneously Formed Buckles on Planar Surfaces

Abstract

This paper describes the spontaneous formation of patterns of aligned buckles in a thin film of gold deposited on the surface of an elastomer [poly(dimethylsiloxane), PDMS]. The surface of the elastomer is patterned photochemically into areas differing in stiffness and coefficient of thermal expansion. The gold is deposited while the surface of the patterned elastomer is warm (T ∼ 100 °C). On cooling, shrinkage in the elastomer places the gold film under compressive stress. The buckles relieve this compressive stress. The distribution of stresses and buckle patterns is described during the pre-and postbuckling regimes using solutions from calculations describing a model comprising a thin stiff plate resting on a thick elastic foundation.

Soft, conformable electrical contacts for organic semiconductors: High-resolution plastic circuits by lamination

“…In fact, we observed excellent properties (mobilities, threshold voltages, on͞off ratios, etc.) in the laminated transistors with every organic semiconductor that we tested: solution-cast regioregular poly(3-hexylthiophene) (p-type) (21) and evaporated films of pentacene (p-type) (22), ␣-sexithiophene (p-type) (23), dihexyl pentathiophene (p-type) (24), copper phthalocyanine (p-type) (25), copper hexadecafluorophthalocyanine (F 16 CuPc, n-type) (26), and several different oligofluorenes (27). In all cases the electrical properties of the laminated transistors are similar to those observed in top contact devices that used shadow mask Au electrodes deposited directly on the semiconductors.…”

“…Fig. 3C shows the transfer characteristics of a laminated organic complementary inverter circuit that uses pentacene and F 16 CuPc (see Inset for the gain) for the p-and n-channel transistors, respectively. Its performance is the same as similar, but larger-scale, top contact devices fabricated by conventional shadow masking.…”

“…The plasma treatment and the deposition of Ti ensure good bonding between the gold and the PDMS: these films easily pass Scotch tape adhesion tests. The thicknesses and deposition conditions were also carefully optimized to minimize any cracking or buckling of the films (15,16).…”

Tunable Nanowrinkles on Shape Memory Polymer Sheets

“…[9] Huck et al augmented this approach with photochemically patterned areas that differ in stiffness and thermal expansion. [15] Watanabe and Hirai more recently developed the very simple approach of simply pre-stretching the PDMS sheet to achieve 6-20 mm striped patterns. [16] Lacour et al used this approach to create stretchable gold conductors.…”

Fabrication of Functional Wrinkled Interfaces from Polymer Blends: Role of the Surface Functionality on the Bacterial Adhesion

“…In effect, the most extended strategy resorts to the use of soft materials with low elastic modulus that can be easily mechanically stretched/compressed. Upon stretching, a rigid layer is either deposited on top of the surface [25,35,36] or created by chemical modification [37,38]. Finally, upon removal of the mechanical force the rigid layer at the surface buckles and finally forms surface wrinkles.…”