Study on micro friction and adhesion force of OTS self-assembled film (II)

The adhesion characteristic of surfaces of SiO2 and the self-assembled film of octadecyltrime-thoxysilane (OTE SAM) on the surface of SiO2 under the r elative humidity of 5 % - 99 % were studied using atomic force microscopy/f riction force microscopy. Experimental results indicate that the adhesion f orce of Sig increases first with the relative humidity and then decreases s harply. However,the adhesion force of OTE SAM surface hardly changes with t he relative humidity due to its strong hydrophobe property. The mechanism o f the adhesion force changing with the relative humidity has been analyzed from the viewpoint of surface tension,van der Walls force,and basic bond fo rces.