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 理论对表面附近的双组分流体（例如大颗粒）进行分析时，我们发现表面诱导层的厚度突然增加，其结构和成分与本体的结构和成分有很大不同。突然的增长伴随着表面之间出现强大的长程吸引力，这是一种转变现象：在表面附近形成第二相，我们测量了表面之间的力。云母我们使用原子力显微镜绘制了甲醇-己烷系统中的表面氮化硅探针（案例 A）和云母表面二氧化硅球（案例 B），绘制了案例 A 中吸引力 L 相对于甲醇浓度 X 的范围。还绘制了情况 B 中表面间距 7.5 nm 处的吸引力 F 相对于 X 的强度。当接近己烷中甲醇的饱和浓度时，L 和 F 都急剧增加，这意味着突然增长然后，我们在乙醇-己烷系统中测量了靠近亲水表面的富含甲醇的层中的力，其范围远大于传统的范德华力。在整个组成范围内作为单相是热力学稳定的。 1.9wt%，吸引力的范围表现出突然增长，这可以解释为表面诱导相变的信号，我们还以我们自己的方式检查了其他研究人员报告的实验数据，并得出结论：表面 -诱导相变确实存在。这对于理解表面或界面发挥关键作用的系统（例如胶体、生物系统等）非常有用。