Tunable Wetting and Adehsion on Reversibly Tunable Wrinkled Surfaces
The ability to actively induce features and textures on surfaces has been of great interest for many potential applications, including stretchable electronics, microlens arrays, MEMS, tunable surface adhesion and friction, and robotics. While many wrinkle structures are formed by heat-induced-strain on PDMS bilayers, we focus on the use of mechanical force, which allows us to separately control the amount and timing of strain applied to the substrate on both planar directions (either simultaneously or sequentially). We demonstrate formation of various submicron wrinkle patterns and their reversible transitions from flat to 1D ripple, to ripple with bifurcation, to ripple/herringbone mixed features, and to well-controlled formation of a highly-ordered zigzag-based 2D herringbone structures.
Currently we study the dynamic tuning of surface properties on such wrinkled surfaces, including adhesion, friction and wetting. We aim to elucidate wetting and adhesion mechanisms by surface chemistry, wrinkle wavelength and amplitude, and the interplay of nano- and microroughness. We will then apply this knowledge to applications, including microfluidics, nanofabrication and cell adhesion.
Lin, P., Vajpayee, S., Jagota, A.*, Hui, C.-H., and Yang, S.*, “Mechanically Tunable Dry Adhesive from Wrinkled Elastomers”, Soft Matter, 2008, 4 , 1830 - 1835. DOI
Chandra, D., Lin, P. and Yang, S.*, “Strain responsive concave and convex microlens arrays”, Appl. Phys. Lett., 2007, 91, 251912. URL
Lin, P. and Yang, S.*, “Spontaneous formation of 1D ripples in transit to highly-ordered 2D herringbone structures through sequential and unequal biaxial mechanical stretching ”, Appl. Phys. Lett. 2007, 90 , 241903. UR