权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

The basic mechanism of the unique long-range interaction force between hydrophobic surfaces

疏水表面之间独特的长程相互作用力的基本机制

基本信息

批准号：
11450290
负责人：
HIGASHTIANI Ko
金额：
$ 6.21万
依托单位：
KYOTO UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B).
财政年份：
1999
资助国家：
日本
起止时间：
1999 至 2000
项目状态：
已结题

项目摘要

Both investigations of the AFM observation of silica plate hydrophobilized by various methods and the simulation of same system are carried out and following things are obtained.As a result of in-situ observation of the surface hydrophobilized by the reaction with a coupling agent in water using AFM, a domain with a height of about 50nm is found out on the surface. Also, simultaneously a phase image, which shows the interaction differs from the circumference in the corresponding place, is obtained. The domain size increases and whole coverage also increased as surface hydrophobicity becomes high. When surface roughness is large, though the number of the domain adsorbed increases, each size decreases and whole coverage also decreases. Then, those domains are identified as air bubbles.Moreover, also for the attraction between hydrophobic surfaces created by adsorption of surfactant molecules, the unique feature such that long-range and the existence of a discontinuous point is found out. … More This feature is similar with the attraction at the time of using a coupling agent, and it is suggested that the trace amount of gaseous phase existing in a system has important influence to the appearance of the attractive force.On the other hand in the simulation, using various L-J type interaction centers, water molecules, dissolved inactive gas molecules and surfactant molecules are modeled. Using this model, the programs of MD method and MC method to calculate interaction forces are developed, and various systems are examined. Consequently, similar results to the case of AFM measurement, that is, attraction with a discontinuous point are obtained and the reason of these phenomena, being based on the bridging generated by the union of concentrated gas layer existing near the surfaces, is found out. However, gravitation generating distance is at most 2nm very small compared with measured value (several 100nm), it is necessary to take the influence of surface roughness into consideration from now on, for example. Moreover, adsorption of the surfactant on the surface is simulated and the surface fine structure is investigated. The results suggested that it is necessary to setup larger surface area than this simulation to coincide the simulation results with the AFM measurement. Less

对不同方法疏水化的二氧化硅板进行了AFM观察和同一体系的模拟研究，得到以下结果：用AFM对在水中与偶联剂反应疏水化的表面进行原位观察，发现在表面上存在高度约为50 nm的畴。此外，同时获得相位图像，其示出了在相应位置处的相互作用不同于圆周。随着表面疏水性的增加，微区尺寸增加，整体覆盖度也增加。当表面粗糙度较大时，虽然吸附的微区数目增加，但各尺寸减小，总覆盖率也减小。此外，还发现了表面活性剂分子吸附在疏水表面上所产生的吸引力具有长程和存在间断点等独特特征。 ...更多信息这一特征与使用偶联剂时的吸引力相似，表明体系中存在的微量气相对吸引力的出现有重要影响。另一方面，在模拟中，使用各种L-J型相互作用中心，模拟了水分子、溶解的惰性气体分子和表面活性剂分子。利用该模型编制了计算相互作用力的MD法和MC法程序，并对各种体系进行了计算。因此，类似的AFM测量的情况下，即具有不连续点的吸引力的结果，并找出这些现象的原因，是基于由存在于表面附近的集中的气体层的工会产生的桥接。然而，与测量值（几百nm）相比，重力产生距离最多为2nm，非常小，因此从现在开始，例如，有必要考虑表面粗糙度的影响。此外，模拟了表面活性剂在表面上的吸附，并研究了表面的精细结构。结果表明，有必要设置比此模拟更大的表面积，以使模拟结果与AFM测量结果相一致。少