Chemical Modification of the Diamond Surface Using Benzoyl Peroxide and Dicarboxylic Acids

We report a new method for introducing carboxylic groups onto the diamond surface. Hydrogenated diamond surfaces were treated in a solvent containing benzoyl peroxide and dicarboxylic acid. Surface characterization was performed by diffuse reflectance infrared Fourier transform spectroscopy. After the reaction, a C O peak appeared, and the shape of the C H peak at 2780−2960 cm - 1 depended on the kind of dicarboxylic acid. When deuterium-labeled diamond powders were treated in the same manner, aliphatic C H peaks were observed in the range 2780−2960 cm - 1 . The C H peaks were assigned to the (CH 2 ) n groups of the dicarboxylic acids bonding to the diamond surface. When the modified diamond surfaces were treated with NaOH(aq), peaks assigned to the C O bond of the COONa groups appeared at 1578 cm - 1, which indicated that carboxylic groups were present on the diamond surface. The presence of HOOC (CH 2 ) n OCO groups on the diamond surface has been demonstrated.