Next Article in Journal
Electro-Active Polymers (EAPs): A Promising Route to Design Bio-Organic/Bioinspired Platforms with on Demand Functionalities
Previous Article in Journal
Hydrogel is Superior to Fibrin Gel as Matrix of Stem Cells in Alleviating Antigen-Induced Arthritis
Previous Article in Special Issue
Surface Property Modification of Silver Nanoparticles with Dopamine-Functionalized Poly(pentafluorostyrene) via RAFT Polymerization
Article Menu

Export Article

Open AccessArticle
Polymers 2016, 8(5), 183; doi:10.3390/polym8050183

Light and Temperature as Dual Stimuli Lead to Self-Assembly of Hyperbranched Azobenzene-Terminated Poly(N-isopropylacrylamide)

1
Jiangsu Key Laboratory of Material Surface Science and Technology, School of Material Science and Engineering, Changzhou University, Changzhou 213164, Jiangsu, China
2
Materials Research Laboratory, Materials Research Institute, The Pennsylvania State University, University Park, PA 16802, USA
3
School of Resource and Metallurgy, Guangxi University, Nanning 530004, Guangxi, China
*
Authors to whom correspondence should be addressed.
Academic Editors: Nicolay V. Tsarevsky and Alexander Böker
Received: 22 February 2016 / Revised: 11 April 2016 / Accepted: 15 April 2016 / Published: 7 May 2016
(This article belongs to the Special Issue Controlled/Living Radical Polymerization)
View Full-Text   |   Download PDF [5481 KB, uploaded 7 May 2016]   |  

Abstract

Hyperbranched poly(N-isopropylacrylamide)s (HBPNIPAMs) end-capped with different azobenzene chromophores (HBPNIPAM-Azo-OC3H7, HBPNIPAM-Azo-OCH3, HBPNIPAM-Azo, and HBPNIPAM-Azo-COOH) were successfully synthesized by atom transfer radical polymerization (ATRP) of N-isopropylacrylamide using different azobenzene-functional initiators. All HBPNIPAMs showed a similar highly branched structure, similar content of azobenzene chromophores, and similar absolute weight/average molecular weight. The different azobenzene structures at the end of the HBPNIPAMs exhibited reversible trans-cis-trans isomerization behavior under alternating UV and Vis irradiation, which lowered the critical solution temperature (LCST) due to different self-assembling behaviors. The spherical aggregates of HBPNIPAM-Azo-OC3H7 and HBPNIPAM-Azo-OCH3 containing hydrophobic para substituents either changed to bigger nanorods or increased in number, leading to a change in LCST of −2.0 and −1.0 °C, respectively, after UV irradiation. However, the unimolecular aggregates of HBPNIPAM-Azo were unchanged, while the unstable multimolecular particles of HBPNIPAM-Azo-COOH end-capped with strongly polar carboxyl groups partly dissociated to form a greater number of unimolecular aggregates and led to an LCST increase of 1.0 °C. View Full-Text
Keywords: poly(N-isopropylacrylamide)s; azo polymers; stimuli-sensitive; self-assembly; hyperbranched poly(N-isopropylacrylamide)s; azo polymers; stimuli-sensitive; self-assembly; hyperbranched
Figures

This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. (CC BY 4.0).

Supplementary material

Scifeed alert for new publications

Never miss any articles matching your research from any publisher
  • Get alerts for new papers matching your research
  • Find out the new papers from selected authors
  • Updated daily for 49'000+ journals and 6000+ publishers
  • Define your Scifeed now

SciFeed Share & Cite This Article

MDPI and ACS Style

Huang, W.; Yang, J.; Xia, Y.; Wang, X.; Xue, X.; Yang, H.; Wang, G.; Jiang, B.; Li, F.; Komarneni, S. Light and Temperature as Dual Stimuli Lead to Self-Assembly of Hyperbranched Azobenzene-Terminated Poly(N-isopropylacrylamide). Polymers 2016, 8, 183.

Show more citation formats Show less citations formats

Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Related Articles

Article Metrics

Article Access Statistics

1

Comments

[Return to top]
Polymers EISSN 2073-4360 Published by MDPI AG, Basel, Switzerland RSS E-Mail Table of Contents Alert
Back to Top