Dispersion of Ultrafine Oxide Particles Utilizing Micromulsion

氧化物微粒在水或非水介质中的稳定分散具有重要意义。在这项研究中，试验中，赤铁矿细颗粒（中值直径和BET比表面积分别为0.47 μ m和5.6 m^2/g）稳定在水介质中，通过使用O/W乳液和O/W微乳液。实验由两个步骤组成：1）在正癸烷中稳定赤铁矿颗粒和2）制备稳定的O/W乳液，其中油滴含有赤铁矿细颗粒。采用两种不同的方法制备了稳定的赤铁矿正癸烷悬浮液。一种方法涉及制备赤铁矿颗粒，其表面通过在水性介质中单层涂覆油酸钠（Na-Ol），然后水洗和干燥而变得疏水。相对稳定的赤铁矿癸烷悬浮液是用在1重量%的赤铁矿水悬浮液中在PH 6下用1 × 10 - 4M Na-01处理的赤铁矿颗粒获得的。<-3>另一种方法inv ...更多信息 使用Aerosol OT将赤铁矿颗粒直接分散到正癸烷中，浓度范围为5 × 10 - 4至1 × 10 - 4 M。<-2><-1>以十二烷基硫酸钠（SDS）为乳化剂，十二烷与水的体积比为1：10，采用超声乳化法制备O/W型乳状液。<-3>用Na-OI法得到的含赤铁矿的O/W乳状液在静置7天或更长时间后仍显示出稳定的分散性，而用AerosolOT法得到的乳状液则显示出较低的稳定性。但后者在正癸烷中的分散稳定性优于前者（5 - 7ml/20ml食用者）加入到含有0.5M SDS的普通O/W乳液中。应用与制备包含赤铁矿的O/W乳液中所用相同的程序以制备包含赤铁矿的O/W微乳液。当普通O/W型乳状液转变为连续加入SDS的微乳状液后，乳状液液滴中的赤铁矿颗粒被挤出并在短时间内沉降下来。少

It is of great significance to get stable dispersions of oxide fine particles in aqueous or non-aqueous media. In this study a trial was in which hematite fine particles (median diameter and BET specific surface area being 0.47 um and 5.6 m^2/g, respectively) are stabilized in aqueous media by utilizing O/W emulsions and O/W micro-emulsions. Experiments consist of two steps; 1) stabilization of hematite particles in n-decane and 2) preparation of stable O/W emulsions in which oil droplets contain hematite fine particles. Two different methods were employed to get stable decane suspensions of hematite. One method involves making hematite particles whose surfaces are made hydrophobic by monolayer coating of sodium oleate (Na-Ol) in aqueous media, followed by water washing and drying. The relatively stable hematite decane suspension was obtained with hematite particles which had been treated with 1x10^<-3> M Na-Ol at PH 6 in aqueous hematite suspensions of 1% by weight. Another method inv … More olves dispersing hematite particles directly into n-decane using Aerosol OT in a concentration range of 5x10^<-2> to 1x10^<-1> M. This suspension revealed much better stability than that obtained by Na-Ol method.O/W emulsion was prepared by ultrasonic method using the hematite decane suspension and water, volume ratio being 1:10, where 1x10^<-3> M sodium dodecyl sulfate (SDS) was used as an emulsifier in both methods. Hematite-included O/W emulsions obtained by the Na-Ol methed revealed stable dispersion even after standing for 7 days or more, while less stability was indicated with those by the Aerosol OT method, in spite of the fact that the latter showed more stable dispersion in n-decane than the former.O/W micro-emulsions were prepared by adding n-butanol (5-7 ml/20 ml eater) into ordinary O/W emulsion containing 0.5 M SDS. The same procedure was applied as used in preparing the hematite-included O/W emulsion in order to make hematite-included O/W micro emulsion. However, hematite particles included in emulsion droplets were squeezed out of the emulsion droplets and settled down within a short period of time after ordinary O/W emulsion had been changed to micro-emulsion with successive addition of sds. Less