【作者】 何会新； 陈海峰； 张华； 陈泳； 刘忠范；

【Author】 HE Xui-xin CHEN Hai-feng ZHANG Hua CHEN Yong LIU Zhong-fan (Center for Intelligent Material Research,College of Chemistry and Molecular Engineering,Peking University,Beijing 100871,China.)

【机构】 北京大学化学与分子工程学院智能材料研究中心；

【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。更多还原

【Abstract】 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（CH₂）₆ SH SAM on gold was first prepared on gold substrate,and a commercial Si₃N₄ 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.更多还原