Grigoriev D O, Krägel J, Dutschk V, Miller R, Möhwald H
Max-Planck Institute of Colloids and Interfaces, Golm/Potsdam, D-14476, Germany.
Phys Chem Chem Phys. 2007 Dec 28;9(48):6447-54. doi: 10.1039/b711732a. Epub 2007 Nov 9.
A novel and simple method for the determination of the contact angle of nano- and microparticles at the liquid/air interface is proposed. The principle is based on the consideration of differences between the pressure/area isotherms of a 2D single-component system of a surfactant and those of binary systems comprised of the same surfactant and the particles to be studied. The theoretical analysis of the contact-angle behavior in this system upon compression allows the prediction of direction of the particles' squeezing out of the surface layer and therefore the distinction between the particles with high contact angle (Theta(p) > 90 degrees) and low (Theta(p) < 90 degrees) hydrophobicity. The application of this method to microparticles of two different hydrophobicities demonstrates good agreement between the obtained contact angles and the corresponding degrees of hydrophobicity given by the particle provider.
提出了一种新颖且简单的方法来测定纳米和微米颗粒在液/气界面处的接触角。该原理基于对表面活性剂二维单组分体系与由相同表面活性剂和待研究颗粒组成的二元体系的压力/面积等温线差异的考虑。对该体系在压缩时接触角行为的理论分析能够预测颗粒从表面层挤出的方向，从而区分高接触角（θp > 90°）和低接触角（θp < 90°）疏水性的颗粒。将此方法应用于两种不同疏水性的微米颗粒，结果表明所获得的接触角与颗粒供应商给出的相应疏水性程度之间具有良好的一致性。
