CO2-switchable behavior of chitosan-g-poly[(2-dimethylamino)ethyl methacrylate] as an emulsifier. (15th August 2017)

• Record Type: Journal Article
• Authors: Shieh, Yeong-Tarng; Lin, Yen-Tzu; Cheng, Chih-Chia
• Is Part Of: Carbohydrate polymers. Volume 170(2017)
• Page Start: 281
• Page End: 288
• Publication Date: 2017-08-15
• Subjects: Chitosan -- Carbon dioxide -- Switchable emulsifiers -- Emulsification/demulsification -- Graft polymers; Polysaccharides -- Periodicals; Polysaccharides -- Periodicals; Polysaccharides -- Périodiques; Electronic journals; 547.78
• DOI: 10.1016/j.carbpol.2017.04.095
• Languages: English
• ISSNs: 0144-8617

Abstract

Graphical abstract: A new water soluble polymer-grafted chitosan possesses a multiple-stimulus response property with CO2 -switchable emulsion behavior. Highlights: Chitosan-based multi-responsive copolymer was synthesized and characterized. Chitosan could manipulate the phase transition behavior in aqueous solution. The copolymer exhibited reversible CO2 /N2 -switchable behavior. Reversible emulsion/de-emulsion could be approached by simple CO2 /N2 bubbling. Abstract: Chitosan- g -poly[(2-dimethylamino)ethyl methacrylate] was investigated as a CO2 -switchable emulsifier in this study. Poly(2-dimethylamino)ethyl methacrylate (PDMAEMA) was prepared by atom transfer radical polymerization followed by grafting to chitosan (CS). The CO2 -responsiveness and reversible CO2 -switchable temperature- and pH-sensitive behavior of PDMAEMA and CS- g -PDMAEMA were investigated as emulsifiers via simple CO2 and N2 bubbling. The lower critical solution temperatures (LCSTs) of PDMAEMA and CS- g -PDMAEMA aqueous solutions both increased as pH decreased to about pH 7.3, at which point the LCSTs disappeared. At elevated temperatures (e.g. 60 °C), CO2 bubbling removed the turbidity in CS- g -PDMAEMA aqueous solution and N2 bubbling restored turbidity. The presence of CS- g -PDMAEMA in a two-phase solution of n -butanol/deionized water enabled the formation of a completely emulsified single phase after CO2 bubbling, which reverted to a two-phase solution on N2 bubbling. Overall, CS- g -PDMAEMA has potential as a CO2 -switchable emulsifier.