Mechanism of adhesion of electroless-deposited silver on poly(ether urethane)

Abstract

Bacterial growth on medical implants and devices is a common source of infection. There is a great deal of interest in the surface modification of polymeric materials to decrease infection rates without altering properties that affect their function. One possibility is to coat the material with an antibacterial agent such as silver. This paper explores the feasibility of depositing adherent silver films onto biomedical poly(ether urethanes) by an electroless plating process. The surface chemistry of the deposition process and the effect of a plasma treatment on the metal/polymer adhesion have been explored. The silver films produced on an unmodified poly(ether urethane) surface consist predominantly of micron-sized clusters that form in solution and are poorly adhered to the surface. However, some small adherent clusters are also deposited on the polymer surface and X-ray photoelectron spectroscopy of the metal/polymer interface shows evidence of chemical interaction between silver and surface carbonyl groups. An air plasma treatment of the polymer to increase the number of carbonyl containing groups at the surface has been shown to significantly improve the metal/polymer adhesion and to decrease the porosity of the silver films. This paper illustrates the importance of chemical bonding in the electroless metallization of polymers.