DISCANT is an experimental approach towards a general model for interactions between nanoparticle dopants and nematic liquid crystals. By studying the impact of gold nanoparticles, carbon nanotubes or toluene molecules on the molecular fluctuation dynamics of a nematic liquid crystal host we are able to correlate phase transition temperatures with rotational fluctuation frequencies. This new approach provides us with deep insight into the strength on dopant-host interactions and its impact on the phase stability of the nematic phase.
Our results indicate that presence of any kind of dopant destabilizes the nematic phase. However, the magnitude of this destabilization is clearly less pronounced for nanoparticle dopants compared to a dilution of the host by toluene. We show that the diverse distribution of toluene or nanoparticles in the liquid crystal host phase is responsible for the difference in doping effects: Agglomeration of nanoparticles limits the maximum nanoparticle load in LC-NP dispersions. Even at the highest possible doping concentration, the average distance between two dispersed particles is magnitudes larger than the molecular dimension of LC molecules. Therefore the fluctuation dynamic of host molecules is rarely affected by the presence of nanoparticles.