摘要
本文提出了利用化学力显微镜直接测量化学键强度的实验方法。其基本思想是设法使待测化学键形成于探针与样品之间，这可以通过适当的分子设计并对探针和基底进行修饰来实现。然后在成键的环境下（如液相、气相或光照等）测量探针与样品间的粘附力，并对其进行统计处理，，即可计算出键能。本文模拟硫醇在金表面上自组装膜的成膜过程，即在无水乙醇溶液中现场检测镀金探针与巯基为末端的自组装膜间的粘附力。然后用ＪＫＲ粘滞理论计算实际成键个数。由此测得Ａｕ－Ｓ键能为３４±５ｋｃａｌ／ｍｏｌ，与理论推算值基本接近。
A novel aproach based on chemical force microscopy(CFM) was proposed for directly measuring the Au S bond energy in thiol self assembled monolayers on gold.Experiments were configured as follows.A HS(CH 2) 6 SH SAM on gold was first prepared on gold substrate, and a commercial Si 3N 4 tip was sputter coated by Au film,which was employed as the CFM tip.Under the experimental condition mimicking the SAM formation process, the adhesion force between the Au coated tip and the SH terminated surface was measured by CFM,which is believed to reflect the bonding strength of Au S linkage.With the help of JKR adhesion theory, we determined the Au S bond energy to be 34kcal/mol,in nice agreement with the thermodynamiclly evaluated result.The method developed here can be applied to many other systems together with suitable molecular designs and surface modifications.
出处
《电子显微学报》
CAS
CSCD
1999年第1期65-68,共4页
Journal of Chinese Electron Microscopy Society
关键词
化学力显微镜
键能
自组装膜
化学键
chemical force microscopy
self assembled monolayer
bond energy
