Surface morphology of randomly disordered liquid crystal

I have studied the quenched random disorder effects created by aerosil dispersion in an octylcyanobiphenyl liquid crystal using atomic force microscopy technique. Liquid crystals have a rich phase variety. The nematic to the smectic-A phase transition in which smectic layers are formed in one dimension while the material is still in a liquid-like condition in two dimensions within the layers is one of the common examples of LC phase transitions. Gelation process in the 8CB+aerosil gels yields a quenched random disorder network which also changes the surface topography. By increasing the aerosil concentration, the original smooth pattern of liquid crystals sample surfaces is suppressed by creating fractal aerosil surface effects; these surfaces become more porous, rougher with more rounded crevices. The dispersed aerosil also serves as pinning centers for the liquid crystal molecules. It has been observed that via the diffusion-limited-aggregation process, aerosil nano-particles yield a fractal-like surface pattern for the less disordered samples. As the aerosil dispersion increases, the surface can be described by more aggregated regions which also introduce more roughness. The results of these analyses, we showed a net correlation between the short-ranged X-Ray peak widths and the calculated surface roughness of the samples. In other words, here we have shown that these quenched random effect gels can also be characterized by their surface roughness.