Tunable Structural Color with Gradient and Multiaxial Polydimethylsiloxane Wrinkling

The generation of structural color from wrinkled polydimethylsiloxane (PDMS) surfaces, fabricated by plasma exposure, subjected to uni- and multi-axial, sequential strain fields is examined. approach based on the well-known, mechanically-induced, buckling instability a supported bilayer, whereby top glassy “skin” formed oxidation. Surface periodicities 200 nm ≲ d 3 μm, encompassing visible spectrum, are investigated in terms observed color, intensity mixing different diffraction orders, exhibiting good agreement with model predictions. By contrast complex fabrication methods, tunability mechanochromic response readily achieved adjusting parameters, dynamically varying (ε 50%). Prescribed directionality, employing uniaxial, isotropic, gradient strain, wave-sum wrinkling superposition, as well skin thickness (and thus d) amplitude gradients, using facile scalable approaches, yield striking spatial variation, homogeneity, directionality.