Woolston Phillip, van Duijneveldt Jeroen S
School of Chemistry, University of Bristol, Bristol BS8 1TS, UK.
School of Chemistry, University of Bristol, Bristol BS8 1TS, UK.
J Colloid Interface Sci. 2015 Jan 1;437:65-70. doi: 10.1016/j.jcis.2014.09.014. Epub 2014 Sep 18.
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 Mg(2+) ions leaching from the clay mineral.
海泡石粘土棒在水中的水悬浮液在浓度增加时往往会形成凝胶。本文展示了添加少量（占粘土质量的0.1%）常见的粘土悬浮液稳定剂聚丙烯酸钠，如何能观察到各向同性-向列型液晶相变。发现添加氯化钠后，该相变会向更高的粘土浓度移动，含10⁻³ M或更高浓度盐的样品仅呈现凝胶相。即使最初形成液晶的样品在几周后也有形成凝胶的趋势，这可能是由于粘土矿物中镁离子的浸出。
