Nano- and microtribological characterization of silanes deposited on cobalt substrate

In this paper, vapor phase deposition was used to grow fluoroalkylsilane films on cobalt surface. The films were characterized by contact angle analyzer for hydrophobicity and X-ray photoelectron spectroscopy (XPS) for identification of fluoroorganic monolayers deposited on the surfaces. Adhesion and friction measurements were performed using atomic force microscope (AFM) and compared with measurements made by microtribometer operated in millinewton (mN) applied load range.Nano- and microtribological measurements show that cobalt modified by fluoroalkylsilanes has lower adhesion and coefficient of friction. The investigation also indicates a decrease of friction coefficient with increasing fluoric alkyl chain length. Covalently bonded fluoroalkylsilanes with longer alkyl chains are found to be a prime candidate for practical use as a lubricant.

Research highlights▶ In this paper, vapor phase deposition was used to grow fluoroalkylsilane films on cobalt surface. The films were characterized by contact angle analyzer for hydrophobicity and X-ray photoelectron spectroscopy (XPS) for identification of fluoroorganic monolayers deposited on the surfaces. Adhesion and friction measurements were performed using atomic force microscope (AFM) and compared with measurements made by microtribometer operated in millinewton (mN) normal load range. ▶ Nano- and microtribological measurements show that cobalt modified by fluoroalkylsilanes has lower adhesion and coefficient of friction. The investigation also indicates a decrease of friction coefficient with increasing fluoric alkyl chain length. Covalently bonded fluoroalkylsilanes with longer alkyl chains are found to be a prime candidate for practical use as a lubricant. To the authors’ knowledge, the mentioned studies have been made for the first time.