Patterning Poly(dimethylsiloxane) Microspheres via Combination of Oxygen Plasma Exposure and Solvent Treatment

Abstract

Here a simple low-cost yet robust route has been developed to prepare poly(dimethylsiloxane) (PDMS) microspheres with various surface wrinkle patterns. First, the aqueous-phase-synthesized PDMS microspheres are exposed to oxygen plasma (OP), yielding the oxidized SiOx layer and the corresponding stiff shell/compliant core system. The subsequent solvent swelling and solvent evaporation induce the spontaneous formation of a series of curvature and overstress-sensitive spherical wrinkles such as dimples, short rodlike depressions, and herringbone and labyrinth patterns. The effects of the experimental parameters, including the radius and Young's modulus of the microspheres, the OP exposure duration, and the nature of the solvents, on these tunable spherical wrinkles have been systematically studied. The experimental results reveal that a power-law dependence of the wrinkling wavelength on the microsphere radius exists. Furthermore, the induced wrinkling patterns are inherently characteristic of a memory effect and good reversibility. Meanwhile, the corresponding phase diagram of the wrinkle morphologies on the spherical surfaces vs the normalized radius of curvature and the excess swelling degree has been demonstrated. It is envisioned that the introduced strategy in principle could be applied to other curved surfaces for expeditious generation of well-defined wrinkle morphologies, which not only enables the fabrication of solids with multifunctional surface properties, but also provides important implications for the morphogenesis in soft materials and tissues.

Patterning Surfaces on Azo‐Based Multilayer Films via Surface Wrinkling Combined with Visible Light Irradiation

“…Here, the v of the glassy polymer films and rubbery substrate is assumed to be 0.33 and 0.5, respectively. [21b] E s is 1.32 ± 0.04 MPa according to our previous report . E PS is assumed to be 3.4 ± 0.2 GPa.…”

“…[ 21b ] E s is 1.32 ± 0.04 MPa according to our previous report. [ 22 ] E PS is assumed to be 3.4 ± 0.2 GPa. [ 14b , 23 ] E PDO3 is estimated to be 1.2 ± 0.3 GPa (Figure S3, Supporting Information), based on the wrinkling-based metrology.…”

Enabling and Localizing Omnidirectional Nonlinear Deformation in Liquid Crystalline Elastomers

“…[7,11] Less appreciated, but equally compelling to functional end uses, is the nonlinear deformation of LCEs to load. [2][3][4][5] Often, these approaches have focused on assimilating the properties of multiple materials in a single structural element. Specifically, when the loading axis is parallel to the molecular orientation (the nematic "director"), the LCE exhibits a linear elastic response.…”

Spatially Configuring Wrinkle Pattern and Multiscale Surface Evolution with Structural Confinement

“…[8][9][10][11][12][13] The latter perspective has enabled engineering opportunities with self-adaptive/autonomous structures in low dimensions and has implications in many different contexts such as micro-/ nanofluidics, [14][15][16] flexible electronics, [17,18] adhesion, [19,20] organic solar cells, [21] tunable optics, [22][23][24] wettability, [25][26][27] and promising methods for surface patterning. [1,[28][29][30][31] While our scientific/technical understanding has advanced, there remains much to be explored about the control of instability morphology, and in particular how to configure instabilities, such as wrinkling and creasing, to desired patterns with selective distribution covering the surface and bespoke thresholds for the formation and evolution of instabilities.…”