凝胶色谱与多角激光光散射联用研究聚氧化乙烯的扩展效应和链构象

Band Broadening and Chain Conformation of Polyethylene Oxide by Gel Permeation Chromatography Coupled with Multi-angle Laser Light Scattering

采用凝胶色谱与多角激光光散射联用的方法,测定了一系列不同分子量的聚乙二醇(PEG)和聚氧化乙烯(PEO)在色谱柱中的扩展效应.扩展因子随PEG/PEO分子量的增加而增大,经扩展效应改正后得到了样品的准确分子量和分子量分布.同时建立了PEO的Z均回转半径Rgz与重均分子量Mw之间的单分散标度关系:Rgz=0.0272 Mw0.56,结果表明,长链PEO在水溶液中由于排除体积效应采取溶胀的无规线团构象.

The band broadening of aqueous gel permeation chromatography columns was studied by coupling with a multi-angle laser light scattering detector,using narrow polyethylene glycol（ PEG） and polyethylene oxide（ PEO） samples. The determined spreading factor of PEG / PEO increased with increasing molecular weight between 4. 0 × 10^3 and 1. 3 × 10^6. True molecular weight distributions of these samples were obtained with band broadening correction. Despite the presence of band broadening in the columns,the monodisperse scaling law between radius of gyration and molecular weight of PEO is established to be Rgz= 0. 0272 Mw^0. 56,indicating that the long PEO chains take a swollen random coil conformation in water due to the presence of excluded volume effect.