Novel pH Responsive Amphiphilic Diblock Copolymers with Reversible Micellization Properties
Author(s)Palaniswamy, R.; Dai, S.; Tam, Michael K. C.; Gan, L.H.
Di-block copolymer of poly[methacrylic acid-block-2-(diethylamino)ethyl methacrylate] [P(MAA-b-DEA)] with narrow molecular weight distribution was synthesized using the atom transfer radical polymerization (ATRP) technique. The micellization behavior of the P(MAA-b-DEA) copolymer in aqueous solution at room temperature and different pH values were examined by potentiometric and conductivity titration, UV-Visible spectrophotometry, ¹H-NMR, static and dynamic laser light scattering. At low pH (< 4.2), core-shell micelles were formed with MAA core and protonated DEA shell. At moderate pH values, the polymer precipitated from water and formed a cloudy solution, where the polymer chains aggregated into larger particles resembling that of a hard sphere induced by electrostatic interactions. At high pH (> 9.5), core-shell like micelles consisting of hydrophobic DEA core and ionized MAA shell were re-established.
Molecular Engineering of Biological and Chemical Systems (MEBCS);
ATRP, laser light scattering, P(MAA-b-DEA), stimuli-responsive