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报道了巯基乙胺自组装膜在不同的时间尺度内表面润湿性的特征变化.利用接触角滴定方法对其表面状态进行实时监控表明,自组装膜由固/液界面转移至固/气界面后,接触角在短时间内经历了一个快速升高过程和一个相对较慢的变化过程.从表面自由能的角度,讨论了该现象的机理.采用不同pH值的缓冲溶液进行接触角滴定,得到了巯基乙胺自组装膜的滴定曲线,从而确定表面pKb值为1.7±0.2.从接触角滴定曲线在长时间内的变化趋势中发现,pKb值无显著变化,但曲线整体向上平移,并且滴定曲线中上下平台的差值随时间增长而减小.
The characteristic changes of surface wettability of mercaptoethylamine self-assembled films on different time scales were reported. Using the contact angle titration method to monitor the surface state in real time, it is shown that the contact angle undergoes a rapid rise process and a relatively slow change in short time after self-assembled film is transferred from the solid / liquid interface to the solid / process. From the perspective of surface free energy, the mechanism of this phenomenon is discussed. The titration curve of the self-assembled membrane of mercaptoethylamine was obtained by the contact angle titration with different pH buffer solutions to determine the surface pKb value of 1.7 ± 0.2. From the trend of the contact angle titration curve over a long period of time, no significant change in pKb value, but the curve as a whole upward translation, and titration curve of the difference between the upper and lower platform decreases with time.