Tunable fluorescent and antimicrobial properties of poly(vinyl amine) affected by the acidic or basic hydrolysis of poly(N-vinylformamide)

Abstract

Synthesis of poly(N-vinylformamide) (PNVF) and its subsequent hydrolysis toconvert it to poly(vinyl amine) (PVAm) were performed. Kinetics of acidic andbasic hydrolysis of poly(N-vinylformamide) (PNVF), and products of hydroly-sis were investigated by using Fourier transform infrared, size exclusion chro-matography,1H NMR, and13C NMR spectroscopies, and thermogravimetricanalysis. It was observed that amide groups did not completely transform intoamine groups by acidic hydrolysis of PNVF while the conversion of amidesinto amine groups via basic hydrolysis of PNVF was complete in 12 h, as con-firmed by spectroscopic measurements. Results of extensive characterizationrevealed significant structural and conformational differences between acidicand basic hydrolysis products. Fluorescence spectroscopy was used for the firsttime to follow the conversion of amide groups into amine groups. The fluores-cence intensity of PVAm obtained from basic hydrolysis of PVNF showed sig-nificant increase with amide/amine conversion. Finally, PVAm obtained fromacidic hydrolysis of PNVF demonstrated potent antimicrobial activity, 10–20times more, against common pathogens for example,C. albicans asfungalstrain andE. coli,S. aureus,B. subtilis,andP. aeruginosaas bacterial strains ascompared to PVAm obtained from basic hydrolysis.