In Situ FTIR-ATR Observation of Phase Transition Behavior of n-Alkane Molecules Induced by Friction Motion on a Metal Interface

By using our newly developed in situ Fourier transform infrared attenuated total reflection (FTIR-ATR) measurement system, the physicochemical property changes of n -alkane on the metal surface have been measured during repeatedly reciprocated friction motion. It was found that the friction force induced the phase transition of liquid n -alkane from melt to rotator phase and orthorhombic phase. In the severer friction condition, it was clarified that the conformational disorder was induced even in the orthorhombic phase by applying the shear stress. From these results, a phase diagram of n -alkane as a function of temperature and friction shear force has been constructed for the first time.