Synthesis of Aldehyde‐Functionalized Fluorescent Micelles by Self‐Assembly of a Hybrid Polymer Constructed by Hyperbranched Conjugated Polymer Core with Aldehyde End groups and Polyethylene Glycol Shell

Abstract

Water‐dispersible fluorescent nano‐/micro‐spheres have been widely used as fluorescent probes in many fields. In this paper, aldehyde‐functionalized fluorescent micelles are synthesized by self‐assembly of end‐modified hyperbranched poly(m‐phenyleneethynylene‐alter‐p‐phenyleneethynylene)(hb‐PMPE). Firstly, hb‐PMPE with ‐Br end‐groups(hb‐PMPE‐Br) is obtained by the polymerization of AB2 monomer PhBr2‐C≡C‐Ph‐C≡CH, then the reaction of hb‐PMPE‐Br with 4‐ethynylbenzaldehyde (EBA) gives end aldehyde‐functionalized hyperbranched polymer hb‐PMPE‐CHO. Hence, hb‐PMPE‐CHO is reacted with NH2O‐MPEG2000 to link PEG chains to the ends of hb‐PMPE‐CHO with partial residual aldehyde end‐groups, resulting in aldehyde‐functionalized amphiphilic polymer hb‐PMPE‐PEG. Fluorescent micelles with aldehyde‐containing fluorescent hb‐PMPE core and PEG shell are obtained by self‐assembling hb‐PMPE‐PEG in water. The micelle diameter is determined by the PEG content in hb‐PMPE‐PEG, which can be controlled by the reaction weight ratio of NH2O‐MPEG2000/hb‐PMPE‐CHO. When the ratio of NH2O‐MPEG2000/hb‐PMPE‐CHO > 0.75/1, micelles with a diameter < 50 nm are obtained. The water dispersion of hb‐PMPE‐PEG‐1/2 micelles (28.9 nm, DLS) emits bright green fluorescence with λmax ∼ 490 nm under UV irradiation, and the emission intensity increases with increasing concentration.This article is protected by copyright. All rights reserved