Surface-initiated ATRIP on silk fibroin in water aqueous at ambient temperature

In this study, surface-initiated atom transfer radical polymerization on silk fibroin was conducted using dimethylaminoethyl methacrylate (DMAEMA) as monomer to produce well controlled grafting silk. First, the amino groups and hydroxyl groups on the side chains of the silk fibroin reacted with 2-bromoisobutyryl bromide (BriB-Br) to obtain efficient macroinitiator for ATRP. The introduction of the 2-bromoisobutyryloxyl groups onto silk fibroin chains was confirmed by Energy Disperse Spectroscopy (EDS). Subsequently, the functional silk fibroin was used as macroinitiator of DMAEMA in water aqueous in conjunction with ferrous chloride (FeCl2 center dot 4H(2)O) / Ethylene Diamine Tetraacetic Acid (EDTA) as a catalyst system. FT-IR characterization of the modified silk substrate showed a peak corresponding to DMAEMA indicating that the polymer had been formed on the silk surface. Scanning electron microscope (SEM) characterization of the grafted silk fibroin showed difference with the photo of untreated silk substrate. The graft chains were cleaved by acid hydrolysis and analyzed by gel permeation chromatography (GPC). The GPC results indicated that the graft layer was well-controlled and low-polydispersity polymer was grafted on the silk substrates.