We investigated by means of polarization microscopy the influence of a magnetic field on the shape and director field of nematic droplets in dispersions of plate-like colloidal particles. To interpret the experimental observations, we put forward a simple theory in which we presume strong anchoring and a sphero-cylindrical droplet shape. This model allows us to extract values for the interfacial tension and the splay elastic constant from the experimental data.

The effect of the dispersed state of graphene is studied as a factor influencing the electrical percolation threshold of graphene/polystyrene nanocomposites. We find the percolation threshold of our nanocomposites, prepared with graphene dispersions with different thermodynamic stabilities, degrees of exfoliation, and size polydispersities, to range from 2 to 4.5 wt %. Connectedness percolation theory is applied to calculate percolation thresholds of the corresponding nanocomposites, based on the premise that size polydispersity of graphene platelets in the corresponding solutions must have a strong influence on it. Theory and experimental results agree qualitatively.