Facile and Efficient Fabrication of Photoresponsive Microgels via Thiol-Michael Addition

• Published in: Macromolecular rapid communications. Vol. 33; no. 22; pp. 1952 - 1957
• Main Authors: Zhang, Hui-Juan, Xin, Yan, Yan, Qiang, Zhou, Li-Lin, Peng, Liao, Yuan, Jin-Ying
• Format: Journal Article
• Language: English
• Published: Weinheim WILEY-VCH Verlag 23.11.2012; WILEY‐VCH Verlag; Wiley; Wiley Subscription Services, Inc
• Subjects: Applied sciences; Azo Compounds - chemistry; Beta; beta-Cyclodextrins - chemistry; Exact sciences and technology; Gels - chemistry; host-guest interaction; Light; microgels; photosensitivity; Physicochemistry of polymers; Polyethylene Glycols - chemistry; Polymers and radiations; Properties and characterization; Sulfhydryl Compounds - chemistry; thiol-Michael addition; Ultraviolet Rays; β-cyclodextrin; Michael addition; Particle size; host-guest interaction; Dithiol; Photoisomerization; photosensitivity; Telechelic polymer; Crosslinking; thiol-Michael addition; Cis trans isomerization; Ethylene oxide copolymer; Experimental study; Sulfur copolymer; β-cyclodextrin; Ethylene oxide polymer; Cyclodextrin; Inclusion polymer; Light sensitive polymer; microgels; Preparation; Radiation effect; Microgel
• ISSN: 1022-1336; 1521-3927
• DOI: 10.1002/marc.201200439

A photoresponsive microgel is designed by the combination of a noncovalent assembly strategy with a covalent cross‐linking method. End‐functionalized poly(ethylene glycol) with azobenzene [(PEG‐(Azo)2)] was mixed with acrylate‐modified β‐CD (β‐CD‐MAA) to form photoresponsive inclusion complex through host–guest interaction. The above photoresponsive complex was cross‐linked by thiol‐functionalized PEG (PEG‐dithiol) via Michael addition click reaction. The photoreversibility of resulted microgel was studied by TEM, UV–Vis spectroscopy, and 1H NMR measurements. The characterization results indicated that the reversible size changes of the microgel could be achieved by alternative UV–Vis irradiations with good repeatability. A light responsive microgel system based on host–guest interaction and Michael addition click reaction has been designed and synthesized under ambient conditions. The dissociation and association of β‐CD/azobene inclusion interaction could be tuned reversibly by alternative UV and visible light irradiations, which results in the reversible size control of the microgel particle.