Di-Stimuli Responsive Poly(<i>N</i>-Isopropylacrylamide-co-Diethylaminoethylmethacrylate) Copolymer: Synthesis, Characterization and Investigation of Aqueous Dispersion Properties

Abstract

We report on the synthesis, characterization and aqueous dispersion properties of well-defined double hydrophilic copolymer with pH- and thermo-responsive segments via atom transfer radical polymerization (ATRP). Poly(N-isopropylacrylamide-co-Diethylaminoethylmeth-acrylate), P(NIPAAm-co-DEAEMA), was prepared by ATRP using methyl-4-bromomethyl benzoate initiator. The product was characterized by proton-nuclear magnetic resonance (1H NMR) and attenuated total reflectance infrared (ATR-IR) spectroscopy. The multi-responsive switching between unimer and two types of micellar aggregates were characterized by temperature-dependent dynamic light scattering (DLS). Self-assembles into two types spherical aggregates in 1 mg/mL (0.0315 mM) aqueous solution, depending on solution pH and temperatures were widely investigated. The result shows two types of aggregate with large (280 nm) aggregate and variable sizes of small (17 nm, 25 nm, 45 nm) aggregates depending on temperature ranges from 26 to 40 °C at pH 4.