This review covers equilibrium and dynamic aspects of surface tension and adsorption,primarily of single non micellar or premicellar and micellar surfactants at the air/water interface.Equilibrium tension data have be...This review covers equilibrium and dynamic aspects of surface tension and adsorption,primarily of single non micellar or premicellar and micellar surfactants at the air/water interface.Equilibrium tension data have been related to the Langmuir adsorption equilibrium isothem and the Gibbs isothem.A minute description of the measurement and the curve analysis of the dynamic surface tension is given.Dynamic adsorption models with the diffusioncontrolled and mixed kinetic mechanisms are discussed in some detail and applied to several sets of data.Apparent diffusion coefficients,inferred from dynamic tension data,and kinetic adsorption parameters,derived from application of the models to the data,are presented and critically evaluated.The adsorption of most of the surfactants examined is slower than predicted by diffusion controlled models.Exceptions are mostly non ionic surfactants and certain alcohols.展开更多
分别以十二烷基二甲基叔胺、十四烷基二甲基叔胺和对二氯苄(XDC)为原料,"一步法"合成了两种季铵盐双子表面活性剂,通过正交实验优化了合成条件,结果表明,当n(叔胺)∶n(XDC)=2.4∶1、反应温度75℃、反应时间2 h时,XDC转化率达...分别以十二烷基二甲基叔胺、十四烷基二甲基叔胺和对二氯苄(XDC)为原料,"一步法"合成了两种季铵盐双子表面活性剂,通过正交实验优化了合成条件,结果表明,当n(叔胺)∶n(XDC)=2.4∶1、反应温度75℃、反应时间2 h时,XDC转化率达到100%;产物结构经红外光谱(FTIR)、核磁共振氢谱(1HNMR)和碳谱(13CNMR)进行了确认。研究了其表面活性,结果表明:25℃时,碳链长度分别为12和14时,表面活性剂临界胶束浓度(CMC)分别为1.36×10-5和2.56×10^(-6)mol/L,表面张力(γCMC)分别为40.71和35.37 m N/m;p C20值分别为5.63和6.18;表面过剩吸附量(Γmax)分别为2.41×10^(-6)和3.09×10^(-6)mol/m^2;分子最小截面积(Amin)分别为0.69和0.54 nm^2。动态表面张力参数n值分别为0.85、0.74,t*分别为1.05和0.27 s,R1/2分别为14.11和69.79 m N/m/s,R=14的双子表面活性剂的动态表面张力优于R=12时。该季铵盐双子表面活性剂与结构相似的季铵盐表面活性剂如十六烷基三甲基溴化铵(CTAB)相比CMC低2个数量级。展开更多
文摘This review covers equilibrium and dynamic aspects of surface tension and adsorption,primarily of single non micellar or premicellar and micellar surfactants at the air/water interface.Equilibrium tension data have been related to the Langmuir adsorption equilibrium isothem and the Gibbs isothem.A minute description of the measurement and the curve analysis of the dynamic surface tension is given.Dynamic adsorption models with the diffusioncontrolled and mixed kinetic mechanisms are discussed in some detail and applied to several sets of data.Apparent diffusion coefficients,inferred from dynamic tension data,and kinetic adsorption parameters,derived from application of the models to the data,are presented and critically evaluated.The adsorption of most of the surfactants examined is slower than predicted by diffusion controlled models.Exceptions are mostly non ionic surfactants and certain alcohols.
文摘分别以十二烷基二甲基叔胺、十四烷基二甲基叔胺和对二氯苄(XDC)为原料,"一步法"合成了两种季铵盐双子表面活性剂,通过正交实验优化了合成条件,结果表明,当n(叔胺)∶n(XDC)=2.4∶1、反应温度75℃、反应时间2 h时,XDC转化率达到100%;产物结构经红外光谱(FTIR)、核磁共振氢谱(1HNMR)和碳谱(13CNMR)进行了确认。研究了其表面活性,结果表明:25℃时,碳链长度分别为12和14时,表面活性剂临界胶束浓度(CMC)分别为1.36×10-5和2.56×10^(-6)mol/L,表面张力(γCMC)分别为40.71和35.37 m N/m;p C20值分别为5.63和6.18;表面过剩吸附量(Γmax)分别为2.41×10^(-6)和3.09×10^(-6)mol/m^2;分子最小截面积(Amin)分别为0.69和0.54 nm^2。动态表面张力参数n值分别为0.85、0.74,t*分别为1.05和0.27 s,R1/2分别为14.11和69.79 m N/m/s,R=14的双子表面活性剂的动态表面张力优于R=12时。该季铵盐双子表面活性剂与结构相似的季铵盐表面活性剂如十六烷基三甲基溴化铵(CTAB)相比CMC低2个数量级。
