Synthesis, Characterization and Self-Assembly of PEG-Aniline Tetramer Block Copolymer

An electroactive block copolymer consisting of methoxy poly(ethylene glycol) (inPEG) and aniline tetramer(AT), mPEG-AT, was synthesized via condensation in the presence of N, N'-dicyclohexylcarbodiimide(DCC). The chemical structure of the copolymer was confirmed by (1)H NMR and FTIR. UV-Vis and cyclic voltammogram methods were used to evaluate the electroactivity of the block copolymer. The particle size was measured by ESEM and DSL methods. The spherical aggregates with diameter of about 125 nm were observed by self-assembly method when the copolymer was dissolved in water. The diameter of spherical aggregates would alter as the variation of aqueous pH when the AT segment was oxidized to its emeraldine form. The possible mechanism of self-assembly of the block copolymer and the pH-sensitivity were discussed.