Amidation of Polyesters Is Slow in Nonaqueous Solvents: Efficient Amidation of Poly(ethylene terephthalate) with 3‑Aminopropyltriethoxysilane in Water for Generating Multifunctional Surfaces

This paper describes surface functionalization of poly­(ethylene terephthalate) (PET) films by transamidation of the ester groups with primary amines. The use of water as a solvent improves tremendously the reaction rate and yield compared to conventionally used alcohols. In this study, PET films were exposed to an aqueous solution of 3-amino­propyl­triethoxy­silane (APTES), which resulted in ester-to-amide reactions on the surface of the film. Hydrolysis of the resulting ethoxy moieties in APTES creates hydroxyl groups that can be used as anchoring points for further modification of PET films. This scheme offers an alternative approach to modify polyesters using water as the solvent.