Mechanical and Tribological Behavior of Branched Polyethyleneimine/Polyacrylic Acid Coatings on Ti6Al4V Substrate

This study investigated the mechanical and tribological properties of branched polyethyleneimine/polyacrylic acid (bPEI/PAA) coatings. (bPEI/PAA) coatings were prepared on Ti6Al4V substrate using layer-by-layer assembly technique. The coatings have good tribological behaviors with the rotating mode under the deionized water. In particular, (bPEI/PAA) 40 has the lowest friction coefficient with the reciprocating mode, about 0.14. The cross-linked network structures were formed with the electrostatic attraction. The amorphous phase of coatings provides a crucial buffer during the loads applying on the surface. The (bPEI/PAA) n coatings have the swelling ability, and there are large decreases of storage modulus and loss modulus in deionized water compared with removing from the deionized water. The excellent tribological properties are ascribed to the cross-linked network structure, amorphous phase, and swelling ability.