Synthesis of amphiphilic poly(N-vinylcaprolactam) using ATRP protocol and antibacterial study of its silver nanocomposite

Atom transfer radical polymerization (ATRP) of N-vinylcaprolactam (NVCL) was studied by uisng ethyl-2-bromoisobutyrate (EIB) as initiator in 1,4-dioxane. It led to controlled radical polymerization of NVCL, with the molecular weight increased along with the conversion of monomer and a relatively narrow molecular weight distribution could be obtained, as determined by gel permeation chromatography. 1H NMR showed that the major population of poly(N-vinylcaprolactam) (PVCL) retained the chain-end functional group. The living nature of the ATRP for NVCL was confirmed by the experiments of PVCL chain extension. PVCL was further investigated for its ability to form micelles in aqueous media. Self-assembling of the amphiphilic PVCL leads to the formation of their micellar aggregates in aqueous media which was confirmed by transmission electron microscope. The critical micelle concentration value was calculated from the photophysical changes of Pyrene-1-Carboxaldehyde by UV absorption studies and was found to be 0.0320 mg/mL. The polymer nanocomposite was synthesized and examined in view of antibacterial effect against Enterococcus faecalis, Staphylococcus aureus, Escherichia coli, Proteus mirabilis, and Klebsiella pneumonae. It was found that polymer nanocomposite possess strong antibacterial activity against Enterococcus faecalis with minimum inhibitory concentration value of 32 mu g/mL. (C) 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012