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Long-Range Interaction between Macroparticles in Binary Fluid Mixture

二元流体混合物中大粒子之间的长程相互作用

基本信息

批准号：
10640489
负责人：
KINOSHITA Masahiro
金额：
$ 1.98万
依托单位：
KYOTO UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1998
资助国家：
日本
起止时间：
1998 至 1999
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-10640489/
关键词：
Solvent Colloidal Particle Surface Surface-Induced Layer Phase Transition Spinodal Point Surface Forces Long-Range Forces 混合溶媒相分離親和性

项目摘要

In analyses using the RHNC theory for two-component fluids near surfaces (e. g., macro-particles), we have found a sudden growth in the thickness of the surface-induced layer whose structure and composition are quite different from those of the bulk. Moreover, the sudden growth is accompanied by appearance of strong, long-range attractive force between surfaces. This is a sort of transition phenomenon : formation of the second phase near the surface that can be called the surface-induced phase transition. We have measured forces between mica surface-silicon nitride probe (case A) and mica surface-silica sphere (case B) in methanol-hexane system using an atomic force microscope. We have plotted the range of the attractive force L against the methanol concentration X in case A. We have also plotted the strength of the attractive force F at the surface separation 7.5nm against X in case B. As the saturation concentration of methanol in hexane is approached, both L and F increase very sharply, which implies a sudden growth in the methanol-rich layer near the hydrophilic surfaces. The forces under high methanol concentration are far longer-range than the conventional van der Waals forces. We have then measured forces between mica surface-silicon nitride probe in ethanol-hexane system. This system is thermodynamically stable as a single phase in the entire composition range. Near ethanol concentration of 。ォ1.9wt%, the range of the attractive force exhibits a sudden growth that can be interpreted as a signal of the surface-induced phase transition. We have also examined the experimental data reported by other researchers in our own way and concluded that the surface-induced phase transition does exist. It will be very useful in understanding the systems where surfaces or interfaces play critical roles (e. g., colloids, biological systems, etc.).

在使用RHNC理论分析表面附近的双组分流体（例如，例如，在一个实施例中，宏观粒子），我们已经发现了一个突然增长的表面诱导层的厚度，其结构和组成是非常不同的，从那些块体。此外，突然的增长伴随着表面之间的强大的、长程的吸引力的出现。这是一种相变现象：在表面附近形成第二相，称为表面诱导相变。用原子力显微镜测量了在甲醇-正己烷体系中云母表面-氮化硅探针（情况A）和云母表面-二氧化硅球（情况B）之间的作用力。我们已经画出了在情况A中吸引力L的范围与甲醇浓度X的关系。我们还画出了B情况下表面间距为7.5nm时引力F的强度与X的关系。当甲醇在己烷中的饱和浓度接近时，L和F都非常急剧地增加，这意味着在亲水表面附近的富甲醇层中的突然增长。高浓度甲醇下的力远比传统的货车范德华力作用范围大。在乙醇-正己烷体系中，我们测量了云母表面-氮化硅探针之间的作用力。该体系在整个组成范围内作为单相是热稳定的。乙醇浓度接近。在1.9wt%时，吸引力的范围表现出突然的增长，这可以解释为表面诱导相变的信号。我们还用自己的方法检验了其他研究者报道的实验数据，得出了表面诱导相变确实存在的结论。这将是非常有用的，在了解系统的表面或界面发挥关键作用（如。例如，在一个实施例中，胶体、生物系统等）。