【2017年整理】第三章表面张力及表面活性剂在界面上的吸附.ppt

第三章表面张力及表面活性剂在界面上的吸附 3.1表面张力与表面自由能 3.1.1 表面张力? (surface tension) 3.1.2表面自由能? (surface free energy) 思考题 表面张力与哪些因素有关？即表面张力受哪些因素影响？ 3.2弯曲液面下的附加压力Curved liquid surfaces with additional pressure 3.2弯曲液面下的附加压力 Young and Laplace Equation ： 毛细现象 弯曲液面的力平衡条件 弯曲液面的力平衡条件 3.3Techniques to measure the surface tension 毛细管升高法(Capillary rise method) 环法(Du-Noüy tensiometer) 板法(the Wilhelmy plate method) 最大气泡压力法(Maximum-bubble-pressure method) 滴重(体积)法(Drop weight or drop volume) 悬滴法(Pendant liquid drop) 吊片法 脱环法(环法) 滴体积法： 停滴法和悬滴法： 3.4.1表面过剩和吉布斯等温吸附式(surface excess and Gibbs adsorption isotherm) 两亲分子在气液界面上的定向排列 两亲分子在气液界面上的定向排列 一些液体的表面张力 一些油水界面张力（20℃） 弯曲液面的力平衡条件 弯曲液面的力平衡条件 弯曲液面的力平衡条件 弯曲液面的力平衡条件 弯曲液面的力平衡条件 弯曲液面的力平衡条件 Question 某表面活性剂的稀溶液，表面张力随浓度的增加而线性下降，当表面活性剂的浓度为10-4 mol/dm3时，表面张力下降了3×10-3 mN/m ,计算表面吸附量Г2(设温度为25℃)；求每平方米上该表面活性剂分子的个数以及每个表面活性剂分子所占有的表面积。 Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. Which is commonly used for dilute solutions of nonionic surfactants containing no other materials. 在实际研究过程中如何计算一非离子表面活性剂的一定浓度和一定温度下的吸附量？ 溶液表面吸附量的计算： For dilute solutions(10-2M or less) containing only one non-dissociating surface-active solute, the Gibbs equation is: Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. For solutions of a completely dissociated surfactant of the 1:1 electrolyte type, M+R-, as the only solute, Since to maintain electron neutrality and , then where is the mean activity coefficient of the surfactant. Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. For 1:1 type ionic surfactant dilute solutions (10-2M or less), Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. Since under these conditions the change in the activity of the non-s