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This work is an investigation of the electrografting of in situ generated 4-sulfonic acid phenyldiazonium salt (PD-SO 3 H) on Nitinol followed by layer-by-layer (LBL) deposition of polyelectrolyte (chitosan and alginate) multilayers (PEM). Nitinol is interesting for many biomedical applications. A great deal of attention has thus been paid to its surface modification in order to impart and/or improve its surface properties. This can be achieved using PEM deposition which requires an adhesion promoter i.e. PD-SO 3 H in this work. Results show the successful electrografting of PD-SO 3 H and the preservation of the TiO 2 surface layer (which provides its biocompatibility to Nitinol) allowed by the gentle conditions used for the in situ generation. Nitinol corrosion resistance has been shown to be preserved. Based on XPS analysis, PD-SO 3 H has been shown to be grafted in its deprotonated form and hypothesis of C-O-M and C-N=N-O-M covalent bonds formation between the grafted layer and the Nitinol surface could be made. It can therefore act effectively as adhesion promoter for PEM deposition as confirmed by the deposition, accumulation and alternation of the deposited chitosan and alginate layers. PEM further improve Nitinol corrosion resistance and its resulting hydrophilicity has been shown to be controlled by the last deposited layer.

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The present work investigates the electrografting of in situ generated 2-bromoisobutyrate p-nitrophenyldiazonium salt (PD-Br) after the electroreduction of its nitro precursor (A-NO 2 Br) into amine on NiTi followed by the surface initiated atom transfer radical polymerization (SI-ATRP) of 2-hydroxyethyl methacrylate (HEMA). Nitinol is interesting for many biomedical applications. A great deal of attention has thus been paid to its surface modification in order to impart and/or improve its surface properties. This can be achieved using SI-ATRP which requires initiator i.e. PD-Br in this work. Results show the effective electrografting of PD-Br and the preservation of the TiO 2 surface layer (responsible for the biocompatibility of Nitinol) made possible by the gentle conditions used for the in situ generation. Nitinol corrosion resistance has been shown to be improved. This SI-ATRP initiator (PD-Br) leads to the successful polymerization of HEMA grafted at the surface of NiTi. Furthermore, the ATRP polymerization of HEMA has a double effect on the corrosion resistance of the modified NiTi. First, the conditions used contribute to a hydrothermal-like treatment which reinforces the TiO 2 layer of NiTi and so its biocompatibility but also its corrosion resistance. Second, the layer of PHEMA grafted further improves the corrosion resistance.