Preparation and characterization of dendrimer layers on poly(dimethylsiloxane) films

Thin organic layers of polyamidoamine (PAMAM) dendrimers on poly(dimethylsi loxane) (PDMS) films were prepared, and their transport properties were eva luated. The surface of the PDMS film was plasma-modified either in air or i n maleic anhydride (MAH) vapor. In the case of the MAH-plasma-treated surfa ce, the majority of anhydride groups were maintained during the plasma trea tment. Stable dendrimer layers were deposited by simple loading of amine-te rminated PAMAM dendrimer solutions on the air-plasma-treated PDMS film to m ake PDMS-dendrimer membranes and were formed by reacting amine groups of th e PAMAM dendrimers with anhydride groups on the MAH-plasma-treated surface to prepare PDMS-anhydride-dendrimer composite membranes. The dendrimer laye rs were characterized using XPS, ATR FT-IR spectrometry, and contact-angle and gas permeance measurements. Both PDMS-anhydride and PDMS-anhydride-dend rimer composite films showed facilitated transport of propylene when coordi nated with silver salts. The propylene permeance and ideal separation facto r over propane were 34 GPU and 340, respectively, at high silver loading.