Research on Amphiphilic Copolymer MIP Micelles Electrochemical Sensor

Abstract

Novel molecularly imprinted polymeric (MIP) micelles were prepared via macromolecule self-assembly of a photo-crosslinkable copolymer, combined with molecular imprinting technique using 4-acetaminophenol as the template molecule. First, an acrylic copolymer poly(DMA-co-HEA-co-EHA-co-St) was synthesized via free radical polymerization using (dimethylamino)ethylmethacrylate (DMA), 2-hydroxy ethylacrylate (HEA), 2-ethylhexyl acrylate (EHA) and styrene (St). Further post functionalization introduced a cross-linkable acrylate side groups into the polymer to form the photo-crosslinkable copolymer using isophorone diisocyanate (IPDI) as bridges. The photo-crosslinkable copolymer and 4-acetaminophenol were dissolved to give copolymer mixed solution. Water as a non-solvent, was added to the mixed solu- tion to induce the self-assembly micellization of the photo-crosslinkable copolymer, during which the template molecules (4-acetaminophenol) was entrapped in the micelles through the interactions between 4-acetaminophenol and the copolymer chain. The properties and morphology of MIP micelles were characterized by dynamic light scattering (DLS), zeta potential and transmission electron microscope (TEM). DLS results showed that the average hydrodynamic diameter was about 70 nm, which was supported by the result from the TEM measurements. The MIP micelle solution prepared was used as a bath solu- tion for electrodeposition. A MIP film was formed in situ on the electrode surface by electrodeposition of the MIP micelles and then crosslinked by UV radiation to lock the structure and improve the stability of the film. Finally the template mole- cules were removed from the film by extraction, leading to 4-acetaminophenol imprinted electrode. The electrochemical per- formance of the MIP electrode was evaluated by cyclic voltammetry (CV) and differential pulse stripping voltammetry (DPSV). The resulting MIP sensor showed good response and selectivity towards 4-acetaminophenol. In addition, this MIP sensor showed excellent selectivity to 4-acetaminophenol, and the interferences from structurely similar analogues were ef- fectively avoided. The linear range was from 1×10