Nano-indentation at the surface contact level: applying a harmonic frequency for measuring contact stiffness of self-assembled monolayers adsorbed on Au.

摘要: In this study, the well-ordered alkanethiolate self-assembled monolayers (SAMs) of varied chain lengths and tail groups were employed as examples for nano-characterization on their mechanical properties. A novel nano-indentation technique with a constant harmonic frequency was applied SAMs chemically adsorbed Au to explore contact mechanics, furthermore interpret how SAM molecules respond an infinitesimal oscillation force without pressing them. Experimental results demonstrated that stiffness along measured displacement SAMs/Au distinguishable using dynamic modulus distinct feature phase angles. Phase angles resulted from relaxing continuation mostly influenced by outermost group molecules. The obviously increased densely packed alkyl chains relatively intense agglomeration head at anchoring site. As consequence, result work is relevant mechanics surface level distinction molecular substances attached solid surface. Furthermore it particularly anticipated identify biological variable qualities under fluid-like micro-environment.