Person:

Burgess, Ian

We report a simple method to pattern wetting properties on thin films of periodic mesoporous organosilica (PMO). A hydrophobic methane PMO thin film was covered by masks and exposed to oxygen plasma to make the unmasked area hydrophilic. The wettability patterns could be revealed only when the films were immersed in water or exposed to moisture. We expect that our method would extend the utility of PMO to such areas as sensing and information security.

Structural hierarchy and complex 3D architecture are characteristics of biological photonic designs that are challenging to reproduce in synthetic materials. Top-down lithography allows for designer patterning of arbitrary shapes, but is largely restricted to planar 2D structures. Self-assembly techniques facilitate easy fabrication of 3D photonic crystals, but controllable defect-integration is difficult. In this paper we combine the advantages of top-down and bottom-up fabrication, developing two techniques to deposit 2D-lithographically-patterned planar layers on top of or in between inverse-opal 3D photonic crystals and creating hierarchical structures that resemble the architecture of the bright green wing scales of the butterfly, Parides sesostris. These fabrication procedures, combining advantages of both top-down and bottom-up fabrication, may prove useful in the development of omnidirectional coloration elements and 3D-2D photonic crystal devices.