十二烷基硫酸钠对聚乙烯吡咯烷酮水溶液黏度特性的影响

Influence of sodium dodecyl sulfate on viscosity characteristics of aqueous polyvinylpyrrolidone solution

利用乌氏黏度计在(30±0.05)℃条件下研究了不同聚乙烯吡咯烷酮(PVP)质量浓度与不同十二烷基硫酸钠(SDS)浓度组合的复合溶液的黏度,观察到PVP-SDS溶液黏度曲线上存在双临界浓度c1和c2,表明在c1和c2之间SDS以束缚胶束形式簇集在PVP高分子链上;研究了不同"比簇集量"的PVP-SDS团簇溶液的比浓黏度特性,发现比浓黏度随PVP质量浓度降低反而显著增大,偏离了单纯PVP溶液而与典型的聚电解质聚丙烯酸钠(Na PAA)溶液相似;计算了PVP-SDS团簇中高分子链的均方末端距r2及其与单纯PVP类比的链相对扩张量k值,发现随着比簇集量[Г]增加k值增大。根据实验结果,将上述现象解释为由于带电的SDS束缚胶束簇集在PVP高分子链上,产生了"聚电解质效应",从而导致高分子链扩张。

Flow time data of aqueous polyvinylpyrrolidone- sodium dodecyl sulfate（ PVP- SDS） complex solutions composed of different PVP mass concentrations（ ρPVP） and SDS concentrations（ cSDS） were examined with Ubbelohde viscometer. Observation results showed that there exists double critical concentrations of SDS,c1 and c2on the flow time plots of PVP- SDS solutions,which means SDS bound- micelles were associated in cluster on PVP chains. It was also found that the reduced specific viscosity（ ηsp/ ρPVP） of PVP- SDS solutions increases with the decrease of ρPVPevidently in lower ρPVPscope,which was different from the behavior of simple aqueous PVP solution but similar to the typical polyelectrolyte sodium polyacrylate solution. The mean square end- to- end distance r^2 and the relative expansion value k of PVP chains in the PVP- SDS cluster as compared with that of the simple PVP chains were calculated,and k values increases with the increase of specific clustered quantity [Г]. Such an abnormal phenomenon in reduced specific viscosity curve was reasonably explained based on the calculation results and was attributed to the coil expansion of PVP chains caused by the charged SDS bound- micelles associated in cluster on PVP chains,which resulted in a unique effect on reduced specific viscosity similar to the ＂polyelectrolyte effect＂.