Self-Assembly and Emulsification of Poly{[styrene-alt-maleic acid]-co-[styrene-alt-(N-3,4-dihydroxyphenylethyl-maleamic acid)]}

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• 作者：Yi Chenglin ; Yang Yiqun ; Zhu Ye ; Liu Na ; Liu Xiaoya ; Luo Jing ; Jiang Ming
• 刊名：Langmuir
• 出版年：2012
• 出版时间：June 26, 2012
• 年：2012
• 卷：28
• 期：25
• 页码：9211-9222
• 全文大小：609K
• 年卷期：v.28,no.25(June 26, 2012)
• ISSN：1520-5827

文摘

Self-assembled polymeric micelles can be used as efficient particulate emulsifiers. To explore the relationship between the structure and the oil鈥搘ater interfacial behavior of the micelle emulsifiers, a new type of amphiphilic random copolymer, poly{(styrene-alt-maleic acid)-co-[styrene-alt-(N-3,4-dihydroxyphenylethyl-maleamic acid)]} (SMA鈥揇opa), was synthesized, self-assembled into micelles, and used as emulsifiers. SMA鈥揇opa was synthesized via an aminolysis reaction between dopamine and commercial alternating copolymer poly(styrene-alt-maleic anhydride) (SMA). Dopamine moiety facilitated the self-assembly of the SMA鈥揇opa in selective-solvent into stable micelles, and increased the adsorption of the SMA鈥揇opa at the oil鈥搘ater interface. Additionally, the structural transition of the self-assembled SMA鈥揇opa52 micelles in response to pH and salinity changes were confirmed by means of TEM, AFM, DLS, aqueous electrophoresis techniques, potentiometric titration, and pyrene fluorescence probe methods. Micelles shrunk with increasing salinity, and flocculation of the shrunken primary micelles occurred at salt concentration exceeding 0.1 M. The micelles swelled with increasing pH, and the disassociation of the SMA鈥揇opa52 micelles occurred at pH above approximately 6.5. The structure of the micelles plays a crucial role in the oil鈥搘ater interfacial performance. Micelles with various structures were used as emulsifiers to adsorb at the styrene鈥搘ater and toluene鈥搘ater interfaces. The emulsifying characteristics demonstrated that self-assembled SMA鈥揇opa52 micelles with moderately swollen structure (at 2 < pH < 6) combine the advantages of the solid particulate emulsifiers and polymeric surfactants, possessing excellent emulsifying efficiency and good emulsion stability. Moreover, the emulsifying performance of the SMA鈥揇opa52 micelles could be enhanced by the addition of salt.