Effect of surface modification on the adhesion enhancement of electrolessly deposited Ag-PTFE antibacterial composite coatings to polymer substrates

• The UV irradiation activates the inert silicon rubber surface.
• The grafting of coupling agent provides the silicon rubber with reactive surface.
• Ag+ ions are “anchored” by N atoms in coupling agent during electroless plating.
• Adhesion of Ag antibacterial coatings to silicon rubber is remarkably improved.
• This simple and cost-efficient method has cheerful prospect for industrialization.

Coupling agent 3-amino propyl triethoxy silane (γ-APTS) was facilely grafted onto silicon rubber through UV irradiation to form the self-assembly monolayer (SAM). N atoms with lone pairs of electrons in the coupling agent then anchored the silver atoms during electroless plating and produced antibacterial coatings with remarkably improved adhesion to substrates. The grafting of coupling agent was verified by X-ray photoelectron spectroscopy (XPS), the coatings adhesion was tested according to ASTM D 3359-02 and their antibacterial activity was characterized by inhibition halo test. The composition of the composite coatings was investigated by energy dispersive X-ray spectrometer (EDS). The surface morphology was revealed by Atom Force microscopy (AFM). The results showed that the adhesion of Ag-PTFE coatings with strong and stable antibacterial activity was tremendously improved to silicon rubber substrates.