Journal of Colloid and Interface Science, Vol.437, 65-70, 2015
Isotropic-nematic phase transition in aqueous sepiolite suspensions
Aqueous suspensions of sepiolite clay rods in water tend to form gels on increase of concentration. Here it is shown how addition of a small amount (0.1% of the clay mass) of a common stabiliser for clay suspensions, sodium polyacrylate, can allow the observation of an isotropic-nematic liquid crystal phase transition. This transition was found to move to higher clay concentrations upon adding NaCl, with samples containing 10(-3) M salt or above only displaying a gel phase. Even samples that initially formed liquid crystals had a tendency to form gels after several weeks, possibly due to Mg2+ ions leaching from the clay mineral. (c) 2014 The Authors. Published by Elsevier Inc.