Base-Assisted Electrografting of Aromatic Amines

Contrary to aliphatic amines, aromatic amines have received less attention for surface modification by oxidation due to the low acidity of their cation radicals. To overcome this limitation, bases are often added into the solution to facilitate or to make the grafting possible. However, there has only been a modest focus on their impact on the grafting efficiency. Here, the anodic behavior of a series of para-substituted anilines was investigated in the presence of different bases to address this issue. From complete sets of Bronsted acidity/basicity data and H-bond acidity/basicity factors for both para-substituted anilines and bases, a grafting efficiency index was proposed as a practical tool to choose the most suitable base for the grafting. As a proof-of-concept for base-assisted grafting of aromatic amines, two aniline/base systems were tested to modify carbon surfaces at lower potential, compared to the modification achieved from pure aniline solutions.