Effects of shear flow on structures of lamellar phase in a nonionic surfactant/water system
Effects of shear flow on structures of lamellar phase in a nonionic surfactant/water system
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DOI：
10.1007/b100297
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发表时间：
2004
期刊：
影响因子：
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通讯作者：
T. Kato;K. Minewaki;K. Miyazaki;Y. Kawabata;T. Shikata;S. Komura;Masatoshi Fujii
中科院分区：
文献类型：
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作者：
T. Kato;K. Minewaki;K. Miyazaki;Y. Kawabata;T. Shikata;S. Komura;Masatoshi Fujii
利用小角中子散射（SANS）、小角光散射（SALS）和剪切应力-剪切速率关系研究了70 °C下剪切流对C16 E7（庚二醇-正十六烷基醚）/水（C16 E7含量为40- 55wt%）体系层状相结构的影响。在剪切速率为0.1-1 s-1时，重复距离达到最小值（称为d *）。随着C16 E7浓度的降低，静止时的重复距离增加，而d * 几乎保持不变，并且几乎等于静止时小角X射线散射线形分析得到的双层膜厚度。这些结果表明，水层被排除在剪切流和层状相分离成表面活性剂丰富和水丰富的区域。虽然没有发生宏观相分离，SALS强度在剪切速率为d * 时达到最大值，这与SANS结果一致。的重复距离的减少的机制进行了讨论有关的层状域的大小的变化。
Effects of shear flow on the structure of a lamellar phase in C16E7(hepta(oxyethylene glycol)-n-hexadecylether)/water system (40–55 wt% of C16E7) at 70 °C are studied by using small-angle neutron scattering (SANS), small-angle light scattering (SALS), and shear stress-shear rate relationships. The repeat distance takes a deep minimum (referred to asd*) at the shear rate 0.1–1 s−1. As the concentration of C16E7decreases, the repeat distance at rest increases whereasd*remains almost constant and nearly equal to the thickness of bilayers obtained from the line shape analysis of small angle X-ray scattering at rest. These results suggest that the water layer is excluded by shear flow and that the lamellar phase segregates into surfactant-rich and water-rich regions. Although macroscopic phase separation does not occur, SALS intensity takes a maximum at the shear rate givingd*, which is consistent with the SANS results. Mechanism for the decrease in the repeat distance is discussed in relation to the change in the size of the lamellar domains.