Surfactant-free synthesis of amphiphilic copolymer of poly(styrene-co-acrylamide) in aqueous emulsion with the assistance of ultrasound

The hydrophilic monomer acrylamide (AM) and hydrophobic monomer styrene (St) have been directly copolymerized in a surfactant-free aqueous emulsion with the assistance of powerful ultrasound. Fourier Transform Infrared spectrocopy (FT-IR), nuclear magnetic resonance (NMR), and differential scanning calorimetry (DSC) measurements revealed that copolymers of AM and St were obtained. Elemental analysis was used to calculate the composition of the copolymer. Size exclusion chromatography (SEC) measurement showed that the molecular weight (MW) of the copolymer is 1.86 x 10(5) g/mol and the polydispersity index (PDI) = 2.31. The self-assembly behavior in different solvents was investigated utilizing laser light scattering (LLS), atomic force microscopy (AFM), and transmission electron microscopy (TEM); the copolymer film showed amphiphilicity, as measured by contact angle goniometry. Copyright (c) 2008 John Wiley & Sons, Ltd.