Colloidal particle-based surface nanotopography with high mechanical stability by thermal fixation for liquid crystal devices

We develop a simple and versatile platform to construct the surface nanotopography of a substrate by thermal fixation of colloidal particles. The micrometer-size particles of polystyrene are dispersed in a random monolayer on a substrate by spin-coating and transformed into hemispherical nanostructures with high mechanical stability under thermal treatment. The experimental results for the structural change of the particles agree well with the calculations in a simple model of the constant-volume. The liquid crystal (LC) alignment on the nanotopographic surface with hemispherical structures is found to increase the symmetry of the electro-optic properties of the LC devices. The colloidal particle-based surface topography with size-scalable nanostructures provides a practical route to the control of interfacial structural orders of the functional molecules on a nanometer-to-micrometer scale. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4739268]