Effects of Added Silica Nanoparticles on the Nematic Liquid Crystal Phase Formation in Beidellite Suspensions
详细信息 查看全文
- 作者：Jasper Landman ; Erwan Paineau ; Patrick Davidson ; Isabelle Bihannic ; Laurent J. Michot ; Adrian-Marie Philippe ; Andrei V. Petukhov ; Henk N. W. Lekkerkerker
- 刊名：Journal of Physical Chemistry B
- 出版年：2014
- 出版时间：May 8, 2014
- 年：2014
- 卷：118
- 期：18
- 页码：4913-4919
- 全文大小：426K
- 年卷期：v.118,no.18(May 8, 2014)
- ISSN：1520-5207
文摘
In this article, we present a study of the liquid crystal phase behavior of mixed suspensions of the natural smectite clay mineral beidellite and nonadsorbing colloidal silica particles. While virtually all smectite clays dispersed in water form gels at very low concentrations, beidellite displays a first order isotropic鈥搉ematic phase transition before gel formation ( J. Phys. Chem. B, 2009, m>113 m>, 15858鈭?5869). The addition of silica nanospheres shifts the concentrations of the coexisting isotropic and nematic phases to slightly higher values while at the same time markedly accelerating the phase separation process. Furthermore, beidellite suspensions at volume fractions above the isotropic鈥搉ematic phase separation, trapped in a kinetically arrested gel state, liquefy on the addition of silica nanospheres and proceed to isotropic鈥搉ematic phase separation. Using small-angle X-ray scattering (SAXS), we probe the structural changes caused by the addition of the silica nanospheres, and we relate the modification of the phase transition kinetics to the change of the rheological properties.