Synthesis of poly[(styrene)- rotaxa-(crown ether)]s via free radical polymerization

• Published in: Polymer (Guilford) Vol. 40; no. 7; pp. 1823 - 1832
• Main Authors: Gibson, Harry W., Engen, Paul T., Lee, Sang-Hun
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01.03.1999; Elsevier
• Subjects: Applied sciences; Crown ethers; Exact sciences and technology; Micelles; Organic polymers; Physicochemistry of polymers; Polymers with particular structures; Polyrotaxanes; Preparation, kinetics, thermodynamics, mechanism and catalysts; Polyrotaxanes; Crown ethers; Micelles; Ethylene oxide polymer; Free radical polymerization; Cyclic polymer; Preparation; Dispersion polymerization; Crown compound; Styrene polymer; Experimental study; Solution polymerization; Amphiphilic polymer; Rotaxane
• ISSN: 0032-3861; 1873-2291
• DOI: 10.1016/S0032-3861(98)00392-9

Poly[(styrene)- rotaxa-(crown ether)]s were synthesized by free radical polymerizations of styrene in the presence of crown ethers using bulky `blocking group' initiators to ensure end-capping for prevention of dethreading. These statistical processes produced only low threading yields, but up to 26% cyclic by mass with large crown ethers. The poly[(styrene)- rotaxa-(crown ether)]s `emulsified' in protic solvents such as methanol and water. The dispersion polymerization of styrene in methanol or water using `42-crown-14' (`42C14') indicated that threading provided stability of the polyrotaxane micelles in such solvents through hydrophilic–hydrophobic phase separation. DSC investigations indicated that the threading prevents the crystallization of the crown ether and allows phase mixing to some extent, since two altered T g's were observed.