Tribological performance of aqueous copolymer lubricant in loaded contact with Si and coated Ti film
This paper concentrates on the tribological performance of the polymer aqueous solution poly(propylene oxide)-poly(ethylene oxide)-poly(propylene oxide), PPO-PEO-PPO. The adsorption process on the metal surface is significantly influenced by the concentration and structure of copolymer, and interaction between the copolymer/substrate. Experiments have been carried out to investigate the tribological properties of this copolymer, such as adsorbed thin film thickness and friction on silicon and titanium surfaces. The thickness of the adsorbed copolymer films were measured by Ellipsometry, and the tribological properties such as friction were investigated with a Pin-on-Disk tribometer. The results show that the triblock copolymer with a longer length PPO chain forms a thicker film of lubricant on the hydrophobic surfaces. It has been found from the Pin-on-Disk tribo-tests that the concentration of copolymer and ratio of the PPO and PEO blocks of aqueous polymer fluid can affect the coefficient of friction (COF).