Mydul Alam Mohammad, Kumar Shrestha Lok, Aramaki Kenji
Graduate School of Environment and Information Sciences, Yokohama National University, Tokiwadai 79-7, Hodogaya-ku, Yokohama 240-8501, Japan.
J Colloid Interface Sci. 2009 Jan 15;329(2):366-71. doi: 10.1016/j.jcis.2008.09.074. Epub 2008 Nov 5.
We have investigated the effects of glycerol on the formation and rheological behavior of cubic phase (I(1)) and related O/I(1) gel emulsion in a water/C(12)EO(8)/dodecane system at 25 degrees C. The phase behavior of the water/C(12)EO(8)/dodecane system was studied by optical observation and structures of different liquid crystalline phases were identified by small-angle X-ray scattering (SAXS) techniques. Addition of dodecane (2 wt%) to aqueous solutions of C(12)EO(8) in a concentrated region (40 wt%) leads to the formation of the I(1) phase (which was absent without the addition of oil). The I(1) phase solubilized some amount of oil and at higher oil concentrations the I(1)+O phase was formed, allowing the preparation of O/I(1) gel emulsion. Rheological measurements have shown that the complex viscosity, |eta( *)|, of the I(1) phase is tremendously high ( approximately 10(7) Pas) and it increases with increasing oil concentration, attains a maximum value near the phase boundary, and then decreases drastically in the I(1)+O region. The increasing |eta( *)| or decreasing tandelta(G('')/G(')) can be ascribed with the interactions among the neighboring micelles. The decreasing trend of the |eta( *)| in the I(1)+O region is simply due to the low volume fraction of the I(1) phase. It has been shown that glycerol decreases the viscosity of the I(1) phase and related gel emulsion, which is due to the I(1)-hexagonal phase (H(1)) microstructural transition. Digital images show the physical appearance of the emulsion, which depends on the glycerol concentration changes from translucent to transparent.
我们研究了在25℃下，甘油对水/C(12)EO(8)/十二烷体系中立方相（I(1)）以及相关的O/I(1)凝胶乳液的形成和流变行为的影响。通过光学观察研究了水/C(12)EO(8)/十二烷体系的相行为，并利用小角X射线散射（SAXS）技术鉴定了不同液晶相的结构。在浓区域（40 wt%）的C(12)EO(8)水溶液中添加十二烷（2 wt%）会导致I(1)相的形成（不添加油时不存在该相）。I(1)相溶解了一定量的油，在较高油浓度下形成了I(1)+O相，从而可以制备O/I(1)凝胶乳液。流变学测量表明，I(1)相的复数粘度|η()|极高（约10^7 Pas），并且随着油浓度的增加而增大，在相边界附近达到最大值，然后在I(1)+O区域急剧下降。|η()|的增加或tanδ(G''/G')的减小可归因于相邻胶束之间的相互作用。I(1)+O区域中|η(*)|的下降趋势仅仅是由于I(1)相的体积分数较低。研究表明，甘油降低了I(1)相和相关凝胶乳液的粘度，这是由于I(1)-六方相（H(1)）的微观结构转变。数字图像显示了乳液的外观，其取决于甘油浓度，从半透明变为透明。
