温度/pH双敏感性接枝共聚物P(MAA-g-NIPAM)相行为研究-陕西师范大学学报期刊社网站

陕西师范大学学报（自然科学版）

专题研究

温度/pH双敏感性接枝共聚物P(MAA-g-NIPAM)相行为研究

李芳，刘守信*，刘侠，张朝阳，余娟，房喻

(陕西省大分子科学重点实验室，陕西师范大学化学与材料科学学院，陕西西安 710062)

李芳，女，硕士研究生，主要从事刺激响应性高分子材料方面的研究.

摘要:

利用大分子单体技术通过自由基溶液聚合合成了不同组成的接枝共聚物聚(甲基丙烯酸-g-N-异丙基丙烯酰胺) (P(MAA-g-NIPAM))，通过UV透光率的测定和荧光探针技术对接枝共聚物在稀水溶液中的相行为进行了研究.结果表明，接枝共聚物P(MAA-g-NIPAM)具有温度和pH值的双重敏感性，不同组成的P(MAA-g-NIPAM)具有基本相同的低临界溶解温度(LCST).当溶液的pH<6时，随着pH值的降低P(MAA-g-NIPAM)的主链从较为松散的线团构象变为较为压缩的线团构象.

关键词：

温度和pH敏感性；接枝共聚物；构象行为；临界相变pH；低临界溶解温度(LCST)

收稿日期：

2007-05-05

中图分类号：

O631

文献标识码：

文章编号：

1672-4291(2007)03-0052-05

基金项目：

国家自然科学基金资助项目（20674048）

Doi:

Phase behavior of temperature- and pH-sensitive poly (methacrylic acid-g-N- isopropylacrylamide) in dilute aqueous solution

LI Fang, LIU Shou-xin*, LIU Xia, ZHANG Zhao-yang, YU Juan, FANG Yu

(Key Laboratory for Macromolecular Science of Shaanxi Province, College of Chemistry and Materials Science, Shaanxi Normal University, Xi′an 710062, Shaanxi, China)

Abstract:

The poly (methacrylic acid-g-N-isopropylacrylamide) graft copolymers with different composition were synthesized by free-radical copolymerization. The phase behaviors of P(MAA-g-NIPAM) in dilute aqueous solutions were investigated by UV transmittance measurement and fluorescence probe technique. The results demonstrated that the P(MAA-g-NIPAM) graft copolymers had temperature- and pH-sensitivities. The different composition graft copolymers had the approximately identical lower critical solution temperature (LCST). When the pH of the P(MAA-g-NIPAM) solution is less then 6, the conformation of P(MAA-g-NIPAM) backbone chain changed from expanded coil to tightly globular one with decreasing solution pH.

KeyWords:

temperature and pH-sensitivity; graft copolymer; conformational behavior; critical phase transition pH; lower critical solution temperature (LCST)