Direct amination of diamond surfaces by electroless treatment in liquid ammonia solution

• An electroless process performed in liquid ammonia has been tested to create amine functional groups at diamond surfaces.
• BDD surfaces have been exposed to a liquid ammonia solution containing persulfate as oxidizer.
• Chemical surface modifications of diamond were followed by XPS analyses.
• The distribution of amino-groups was studied by gold nanoparticles immobilization.
• This combined approach proved the growth of amino groups at the diamond surface during the electroless treatment.
• The method is applicable to different diamond surfaces either conductive or not-conductive.

Diamond presents many interesting properties in terms of biocompatibility, chemical inertness and is attractive for applications notably in the biosensor field. The formation of amine functional groups at the diamond surface is of great interest for biomolecule's immobilization. In this work, we present for the first time, the “electroless” amination of diamond surfaces exposed to a liquid ammonia solution containing persulfate. Chemical surface modifications were followed by XPS analyses, while the distribution of amino-groups was studied by gold nanoparticles immobilization. This combined approach proved the growth of amino groups at the diamond surface during the electroless treatment.