中文摘要：

通过多重光散射法研究了纳米Ti O_2水分散体系稳定性的影响因素。探讨了分散剂类型、p H和Na Cl质量浓度对水分散体系稳定性的影响规律以及分散剂对纳米Ti O_2颗粒在分散液中粒径变化、沉降的微观作用特性。结果表明：纳米Ti O_2颗粒的粒径在100~200 nm时易相互吸附团聚沉降,分散剂会在纳米Ti O_2颗粒表面吸附形成双电层,产生更大的Zeta电位负值,增强颗粒间的排斥作用,减缓粒径增长和颗粒沉降,从而提升分散液的稳定性;纳米Ti O_2颗粒的较佳分散条件为：w（六偏磷酸钠）=0.05%,p H=9~10且不加电解质Na Cl;多重光散射法与传统的吸光度测试实验所得结果基本相符。

英文摘要：

Factors that affecting the stability of nano- Ti O_2 aqueous dispersion system were studied using multiple light scattering technique. Affecting rule with respect to type of the dispersing agent,the p H value and electrolyte mass concentration as well as the dispersing agent for microscopic action characteristics of particle size change and settlement of Ti O_2 particles in aqueous dispersion was examined. The results showed that nano- Ti O_2 particles between 100 to 200 nm is more easily to settle due to mutual adsorption and aggregation.The dispersing agent will be adsorbed on surface of nano- Ti O_2 particles and forming double electric layer;generating higher Zeta potential negative value; resulting in the enhancement of the repulsion forces between particles; thereby retarding the increase of particle size and settling migration of the particles. Subsequently,the stability of the dispersion increases. The optimal dispersion conditions are recommended as using sodium hexametaphosphate with a mass fraction of 0. 05%,keeping the p H value within 9 to 10 and without addition of Na Cl. The results obtained with multiple light scattering technique is basically conformed to that obtained from the conventional absorbance tests.