New Amphiphilic Poly(2-ethyl-2-oxazoline)/ Poly(L-lactide) Triblock Copolymers

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• 作者：Chau-Hui Wang and Ging-Ho Hsiue
• 刊名：Biomacromolecules
• 出版年：2003
• 出版时间：November 2003
• 年：2003
• 卷：4
• 期：6
• 页码：1487 - 1490
• 全文大小：71K
• 年卷期：v.4,no.6(November 2003)
• ISSN：1526-4602

文摘

A new series of cationic, thermo-sensitive, and biodegradable poly(L-lactide)-poly(2-ethyl-2-oxazoline)-poly(L-lactide) (PLLA-PEOz-PLLA) triblock copolymers were synthesized by ring-opening polymerization.With increasing molecular weight and crystallinity of hydrophobic PLLA blocks, the critical micellizationconcentrations (CMC) occurred at lower concentration. The PLLA-PEOz-PLLA aqueous solution wastransparent at room temperature. Heating the solution resulted in precipitations, which were caused by thecombination of dehydration of water around PEOz and the aggregations of PLLA segments. Acid/basetitration profiles indicated that PLLA-PEOz-PLLA were protonated at neutral and acidic conditions.Considerable buffering capacity was found over the entire pH range. The specific PLLA-PEOz-PLLAtriblock copolymers with thermal- and pH-sensitive properties can be tailored by varying the compositionsand can be applied as controlled release carries for biomedical applications.