P(NIPAM-co-NVP)共聚物分子链水溶液中的可逆聚集研究

用溶液聚合方法合成了线型聚(N-异丙基丙烯酰胺-co-N-乙烯基吡咯烷酮)共聚物,通过弹性光散射(elastic light scattering,ELS)、荧光光谱与动态光散射研究了共聚物水溶液分子链可逆聚集的温度和时间依赖性.研究表明,升温时,ELS强度增加,分子链聚集;降温时,ELS强度降低,聚集的分子链解离.荧...

REVERSIBLE AGGREGATION OF POLY(N-ISOPROPYLACRYLAMIDEco-N-VINYLPYRROLIDONE)COPOLYMERS IN AQUEOUS SOLUTIONS

Poly(N-isopropylacrylamide-co-N-vinylpyrrolidone) P(NIPAM-co-NVP)] copolymers were synthesized,and their reversible aggregation in aqueous solutions were investigated in the whole heating and cooling process with elastic light scattering(ELS) spectroscopy,fluorescence and dynamic light scattering(DLS).The ELS results indicated that IELS gradually increases in the heating process while decreases in the cooling process.Fluorescence spectra also suggested that the hydrophobic interaction occurred during heating and caused the aggregation of copolymer molecular chains and the increasing of fluorescence intensity,while the intensity was opposite during cooling owning to the dissociation of molecular chains.When the temperature increased,the hydrodynamic radius of this copolymer molecules measured by DLS increased rapidly at the LCST value and then decreased,and the cooling process was also contrary to the heating.Thus,fluorescence spectra and light scattering confirmed with the elastic light scattering in measuring the aggregation behavior of copolymer chains.Besides,ELS can get the conclusion easily that the copolymer with hydrophilic comonomer NVP has a higher transition temperature than the PNIPAM homopolymer has.It was concluded that reversible aggregation of P(NIPAM-co-NVP) copolymers in aqueous solutions could be described by ELS as well as by Fluorescence and DLS.