Issue 34, 2016

Aggregation-induced emission polymer nanoparticles with pH-responsive fluorescence

Abstract

Aggregation-induced emission (AIE) polymer nanoparticles (PNPs) including spherical and cylindrical micelles and vesicles were prepared to have a pH-tunable fluorescence response by virtue of the amphiphilic block copolymer self-assembly technique. The poly(M1)-b-poly(M2-co-M3) block copolymers were prepared from ring-opening metathesis polymerization (ROMP) of norbornene-based monomers M1, M2, and M3, in which the hydrophilic poly(M1) had poly(ethylene glycol) side chains and the hydrophobic poly(M2-co-M3) possessed reactive pentafluorophenyl ester (in M2) and AIE-active tetraphenylethene (in M3) side groups. The spherical and cylindrical micelles and vesicles were then self-assembled from poly(M1)-b-poly(M2-co-M3) with different block ratios in selective solvents of THF/water. This produced self-assembly with hydrophobic microdomains aggregated by poly(M2-co-M3) blocks and dispersing shells formed by hydrophilic poly(M1) blocks. In the presence of reactive pentafluorophenyl ester groups, the hydrophobic microdomains could be crosslinked by reacting with the diamine crosslinkers to chemically fix the self-assembly morphology and produce the stable PNPs. Based on the same activated ester chemistry, stable PNPs with varied morphologies and pH-responsive AIE properties were prepared by further post-functionalizing the crosslinked hydrophobic microdomains. Using N,N-diethylethylenediamine as a post-functionalization agent to introduce the diethylamino groups, the resultant PNPs emitted weak fluorescence when the pH < 4 and strong fluorescence when the pH > 5 in water. Comparatively, using β-alanine as a post-functionalization agent to introduce the carboxylic groups, the resultant PNPs emitted weak fluorescence when the pH > 10 and strong fluorescence when the pH < 8 in water. In addition, the pH-dependant fluorescence “turn on/off” properties were obtained for the post-functionalized PNPs when reversibly varying the pH value of the aqueous solution between 2 and 11.

Graphical abstract: Aggregation-induced emission polymer nanoparticles with pH-responsive fluorescence

Supplementary files

Article information

Article type
Paper
Submitted
12 Jun 2016
Accepted
19 Jul 2016
First published
20 Jul 2016

Polym. Chem., 2016,7, 5386-5395

Aggregation-induced emission polymer nanoparticles with pH-responsive fluorescence

Y. Zhao, W. Zhu, L. Ren and K. Zhang, Polym. Chem., 2016, 7, 5386 DOI: 10.1039/C6PY01009A

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements