Anchoring of alkylphosphonic derivatives molecules on copper oxide surfaces

In this study, a new approach of copper surface modification, taking advantage of the oxide layer naturally present, is proposed using phosphonic acids derivatives. Phosphonic acids are a class of molecules particularly known for their spontaneous self-assembly on oxidized substrates. On this basis, copper substrates chemically oxidized using H2O2 (5%) were successfully modified with n-dodecylphosphonic acid and 1-pyrrolyl-10-decanephosphonic acids. The oxidation state of copper substrate, just after chemical oxidation, was probed by XPS and PM-IRRAS. Surface characterization was completed by contact angle and AFM measurements. Molecular integrity, alkyl chain ordering and wettability were evaluated for both elaborated coatings. The panel of characterization tools used demonstrates the efficient grafting of phosphonic acid compounds on oxidized copper surfaces. The grafting mode appears similar for both investigated molecules and is evaluated as a tridentate mode.