The nature of the liquid crystal (LC) alignment in devices is a crucial parameter in the operating efficiency of these devices and there are numerous methods to induce LC alignment. Nanopatterned substrates of polymers including PMMA and PTFE are known to influence the LC alignment due to the confinement. Nanopatterned polymer substrates created using the NanoIndenter have dimensions 500nm x 500nm x 100nm. Following this procedure, the LC alignment is studied after its deposition these nanopatterned surfaces. The LC alignment variation is observed using a Polarizing Optical Microscope (POM). The POM images will be analyzed to map the pixel values to LC alignment in different patterns like grid structures and grooves. Also, finite difference modeling is used to study the theoretical nature of the LC alignment. The Simulated Annealing algorithm is used to minimize the energy of the LC on the patterned surface. Various boundary conditions like anchoring on the side and top walls and surface anchoring strengths will be applied to observe the nature of the resulting alignment. Modeling results of the LC alignment, when performed on different patterns like square grids, triangular and sawtooth shaped substrates shall be compared with the experimental results.
Holographically-formed Polymer Dispersed Liquid Crystals (H-PDLCs) are electro-optic devices containing alternating planar layers of polymer and liquid crystal droplets. Here, we investigate the effects of patterned polymer layers on the liquid crystal alignment. Three types of polymers were investigated: urethane resin, Poly Tetra Fluoro Ethylene (PTFE) and Poly Methyl Methacrylate (PMMA). Nanopatterns of the form of square grids were formed on the polymer using the MTS Nano-Indenter in the scratch mode. Liquid crystal deposition on these structures showed unique alignment effects at the polymer interface. The polymers were examined under the Atomic Force Microscope and alignment of the liquid crystals was observed by Polarizing Optical Microscopy.