Liquid Crystals and Nanoparticles: Convergence of the Smectic A Correlation Length Independent of Concentration

We performed an X-ray study as a function of temperature on the monomer M6R8 with a 7, 15 and 30% wt of TiO2 nanoparticles and compared it to the 0% or pure monomer. The pure monomer has a phase sequence of Crystal –sm-C (54.7C) – sm-A (80C)-isotropic (97.0C). We have found that this phase sequence is preserved and there is not a large variation in temperature independent of the concentration. There is a peak associated with the interaction between the monomer and the nanoparticle that appears as a shoulder peak to the monomer peak. There is a large variation in this peak that characterizes the sm-C for all concentrations but not the peak that characterizes the sm-A. The correlation length for the sm-A peak converges toward the same value, independent of concentration. There is also a lower angle peak that appears when we add the nanoparticle, but whose correlation length also converges towards the sm-A phase, independent of the concentration. We conclude that independent of the concentration with which the liquid crystal is doped there is a terminal concentration that stays with the liquid crystal.