Relaxation of director reorientations in nanoconfined liquid crystal: Dynamic light scattering investigation

We present the results of dynamic light scattering investigations of the influence of confinement and interfaces on the behavior of nematic liquid crystals filled with aerosil particles and confined in porous matrices with cylindrical pores. The experiments show significant changes in the relaxation properties of LC in these systems. We discuss two well-defined relaxation processes observed for filled and confined liquid crystals in the nematic phase. The first process was qualitatively associated with nematic director orientational fluctuations similar to those seen in bulk liquid crystal. The second relaxation process (with relaxation time slower than the first one) was most likely due to the fluctuations in layers nearest to the solid pore wall/Aerosil particle surface. The results provided evidence for dynamic behavior of the slow relaxation of director orientational fluctuations similar to that of glass-forming liquids although such behavior is not observed in bulk liquid crystals.