水分散介质中离子浓度对聚苯乙烯微球粒径表征的影响

Effect of ion concentration on particle size of ploystyrene microsphere dispersed in water

为研究水分散介质中离子浓度对聚苯乙烯微球粒径大小的影响,以4种不同纯度水样为分散介质,其中超纯水(电阻率≥18MΩ·cm)为空白溶液,分析其平均粒径大小,探讨在不同含盐量的分散介质中样品平均粒径的变化。结果表明:以超纯水为分散介质,聚苯乙烯微球表面存在水化膜,使得粒径测量值大于粒子标称值,而少量离子的加入可以有效破除或压缩聚苯乙烯微球表面的水化膜,从而提高测试准确性,实现标准样品对粒径测量仪器的标定,为样品粒径测试中氯化钠或氯化钾溶液浓度的确定提供依据。

In order to study the effect of ion concentration on particle size of ploystyrene microsphere in water dispersion medium,the average particle diameters of polystyrene microsphere dispersed in four different purity water samples were analyzed.The changes of the particle sizes with various salt contents were also studied with ultrapure water as blank solvent.The resistivity of ultrapure water was more than 18 MΩ·cm.The results show that thick hydration layers will be formed on the surfaces of polystyrene particles in the ultrapure water to increase the measured values of the particle sizes,and the hydration film thickness can be collapsed or compressed by adding a small amount of ion to improve the measurement accuracy,thereby it can realize the verification of particle size measuring instrument with standard sample.Moreover,it is of advantage to choose the concentrations of NaCl or KCl solutions during the tests of the average particle diameters.