Experimental Study on Adsorption Film Thickness of Protein Aqueous Lubricants under Impact Load

The growth characteristics of the adsorbed protein film in a ball-on-disk contact were studied under cyclic impact load in protein aqueous solutions by interferometry. The effects of protein composition, hydrophobic interaction and impact conditions on the adsorption film thickness were investigated. It is found that the thickness of adsorption film of protein under dynamic impact was much higher than that by static adsorption, and the adsorption film grew in the contact area and a constant thickness was reached at last. The steel ball and hydrophobic disk surface were more conducive to the growth of protein adsorption film than the ceramic ball and the hydrophilic disc surface. At the same time, it is found that the adsorption film thickness was independent of the protein concentration, but it had a marked relation with the type of the proteins. The globulin showed stronger adsorption performance than the albumin.