Controlling the surface buckling wrinkles by patterning the material system of hard-nano-film/soft-matter-substrate
Wrinkling and buckling of nano-films on the compliant substrate are always induced due to thermal deformation mismatch. This paper proposes effective means to control the surface wrinkling of thin film on the compliant substrate, which exploits the curvatures of the curve cracks designed on the stiff film. The procedures of the method are summarized as: 1) curve patterns are fabricated on the surface of PDMS (Polydimethylsiloxane) substrate and then the aluminum film with the thickness of several hundred nano-meters is deposited on the substrate; 2) the curve patterns are transferred onto the aluminum film and lead to cracking of the film along the curves. The cracking redistributes the stress in the compressed film on the substrate; 3) on the concave side of the curve, the wrinkling of the film surface is suppressed to be identified as shielding effect and on the convex side the wrinkling of the film surface is induced to be identified as inductive effect. The shielding and inductive effects make the dis-ordered wrinkling and buckling controllable. This phenomenon provides a potential application in the fabrication of flexible electronic devices.