Study on stimuli responsive complex micelles prepared by hydrogen bonding interactions

Two amphiphilic block copolymers poly(t-butyl acrylate)-b-poly(N-isopropylacrylamide) and poly(t-butyl acrylate)-b-poly[2-(dimethylamino) ethyl methacrylate] (PtBA-b-PDMAEMA) were synthesised by atom transfer radical polymerisation reaction. Then, PtBA-b-PDMAEMA was hydrolysed to prepare poly(acrylic acid)-b-poly[2-(dimethylamino) ethyl methacrylate] in an acidic medium. H-1 NMR spectroscopy was used to characterise the chemical structure of the block copolymers. The complex micelles were prepared under the condition of 25 degrees C and pH 5.5. It has been found that their stimuli response behaviour changed with different temperature and pH in solutions which were investigated by a Zetasizer Nano ZS Instrument. The morphology of complex micelles was characterised by TEM. Core shell structure and corona of the micelles were observed obviously from the TEM images. Moreover, the hydrogen bonding interaction in complex micelles was studied by Fourier transform infrared spectroscopy.