摘要
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.荧光光谱研究表明,分子链在升温时发生了疏水缔合相互作用,从而使得分子链聚集体荧光强度增加,降温时分子链发生解离,使荧光强度减弱.动态光散射测得升温时聚合物的平均流体力学半径在最低临界溶解温度(LCST)时急剧增大,而后减小,降温过程的变化与升温相反.此外,从弹性光散射容易得出,共聚物因含有亲水性NVP而使其LCST高于PNIPAM均聚物.可见,通过弹性光散射、荧光光谱和动态光散射得到的共聚物分子链在水溶液中的可逆聚集行为是一致的.
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.
出处
《高分子学报》
SCIE
CAS
CSCD
北大核心
2011年第7期766-771,共6页
Acta Polymerica Sinica
基金
国家自然科学基金(基金号50973129
50673104)
广东省自然科学基金(基金号7003702
7001781)
中科院纤维素化学重点实验室项目(项目号LCLC-2005-168)资助
