Ultrathin Coatings by Multiple Polyelectrolyte Adsorption/Surface Activation (CoMPAS)

A new versatile method for the preparation of thin polymer coatings is presented. It is based on the adsorption of reactive polyelectrolytes by electrostatic interactions. In a following activation step, the adsorbed polymers are modified by reacting with low molar mass reagents carrying the complementary charge, in order to induce charge reversal on the surface. This process allows regular layer-by-layer growth. Using coupling reactions that destroy or create dyes, in particular with donor−acceptor substitution, the multilayer growth can be easily followed. Coupling of azo dyes, aldol condensations of cyanine dyes and analogues, or Michael addition of reactive dyes was found to be particularly useful. The resulting multilayers inherently have a noncentrosymmetric structure.