Organization of poly(2-ethyl-2-oxazoline)-block-poly(2-phenyl-2-oxazoline) copolymers in water solution

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• 作者：Barbara Trzebicka ; Neli Koseva ; Violeta Mitova ; Andrzej Dworak
• 关键词：Poly(2-ethyl-2-oxazoline)-b-poly(2-phenyl-2-oxazoline) ; Aggregates ; Micelles
• 刊名：Polymer
• 出版年：2010
• 出版时间：28 May 2010
• 年：2010
• 卷：51
• 期：12
• 页码：2486-2493
• 全文大小：730 K

文摘

Diblock copolymers were prepared from 2-ethyl-2-oxazoline and 2-phenyl-2-oxazoline via living cationic polymerization using sequential addition of the monomers. Copolymer assemblies in aqueous solutions and on surface were studied with respect to changes in the hydrophilic-hydrophobic balance induced by increasing the length of the hydrophobic poly(2-phenyl-2-oxazoline) segment while the hydrophilic poly(2-ethyl-2-oxazoline) chain was kept constant with an average of 60 monomer units. The copolymer with a short segment of four 2-phenyl-2-oxazoline units assembled into highly hydrated aggregates that decreased twice in size after drying. Their structure was destroyed and network morphologies were formed upon spin-coating. The increase of the length of the hydrophobic segment resulted in aggregates that dissociated to micelle-sized particles when subjected to mechanical shear by spin-coating or filtering. These observations imply that the aggregates are multi-core structures originating from the assembly of primarily formed micelles. The copolymer self-assembly was evidenced by a combination of techniques: DLS, SLS, AFM and SEM.