Department of Interfacial Phenomena, Faculty of Chemistry, Maria Curie-Skłodowska University, Maria Curie-Skłodowska Sq. 3, 20-031 Lublin, Poland.
J Colloid Interface Sci. 2011 Feb 1;354(1):396-404. doi: 10.1016/j.jcis.2010.09.063. Epub 2010 Sep 29.
Measurements of the advancing contact angles for aqueous solutions of sodium dodecyl sulfate (SDDS) or sodium hexadecyl sulfonate (SHS) in mixtures with methanol, ethanol, or propanol on a quartz surface were carried out. On the basis of the obtained results and Young and Gibbs equations the critical surface tension of quartz wetting, the composition of the surface layer at the quartz-water interface, and the activity coefficients of the anionic surfactants and alcohols in this layer as well as the work of adhesion of aqueous solutions of anionic surfactant and alcohol mixtures to the quartz surface were determined. The analysis of the contact angle data showed that the wettability of quartz changed visibly only in the range of alcohol and anionic surfactant concentration at which these surface-active agents were present in the solution in the monomeric form. The analysis also showed that there was a linear dependence between the adhesion and the surface tension of aqueous solutions of anionic surfactant and alcohol mixtures. This dependence can be described by linear equations for which the constants depend on the anionic surfactant and alcohol concentrations. The slope of all linear dependence between adhesion and surface tension was positive. The critical surface tension of quartz wetting determined from this dependence by extrapolating the adhesion tension to the value equal to the surface tension (for contact angle equal zero) depends on the assumption whether the concentration of anionic surfactant or alcohol was constant. Its average value is equal to 29.95mN/m and it is considerably lower than the quartz surface tension. The positive slope of the adhesion-surface tension curves was explained by the possibility of the presence of liquid vapor film beyond the solution drop which settled on the quartz surface and the adsorption of surface-active agents at the quartz/monolayer water film-water interface. This conclusion was confirmed by the work of adhesion of aqueous solutions of anionic surfactants and short-chain alcohol mixtures to the quartz surface determined on the basis of the contact angle data and molar fraction of anionic surfactants and alcohols and their activity coefficient in the surface layer.
测量了十二烷基硫酸钠（SDDS）或十六烷基磺酸钠（SHS）在甲醇、乙醇或丙醇混合物水溶液在石英表面上的前进接触角。根据所得结果和杨格和吉布斯方程，确定了石英润湿的临界表面张力、石英-水界面的表面层组成以及该层中阴离子表面活性剂和醇的活度系数，以及阴离子表面活性剂和醇水溶液在石英表面的附着力。接触角数据的分析表明，只有在醇和阴离子表面活性剂的浓度范围内，这些表面活性剂在溶液中以单体形式存在时，石英的润湿性才会明显改变。分析还表明，阴离子表面活性剂和醇水溶液的附着力与表面张力之间存在线性关系。这种关系可以用线性方程来描述，常数取决于阴离子表面活性剂和醇的浓度。所有附着力与表面张力之间的线性关系的斜率均为正。从这种关系通过将附着力张力外推到等于表面张力（对于接触角等于零）来确定的石英润湿的临界表面张力取决于阴离子表面活性剂或醇的浓度是否保持不变的假设。其平均值等于 29.95mN/m，明显低于石英表面张力。附着力-表面张力曲线的正斜率可以通过存在超出在石英表面上沉降的溶液液滴的液体蒸气膜以及表面活性剂在石英/单层水膜-水界面的吸附来解释。这一结论得到了基于接触角数据和阴离子表面活性剂和短链醇在表面层中的摩尔分数及其活度系数确定的阴离子表面活性剂和短链醇水溶液在石英表面的附着力的证实。
