Surface chemistry of nanoscale Fe_3O_4 dispersed in magnetic fluids

作     者：Bernd GüNTHER 

作者机构：Fraunhofer Institut für Fertigungstechnik und Angewandte MaterialforschungD-28359 Bremen Germany 

出 版 物：《Science China Chemistry》 (中国科学（化学英文版）)

年 卷 期：2007年第50卷第6期

页      面：754-758页

核心收录：

学科分类：081704[工学-应用化学] 07[理学] 08[工学] 0817[工学-化学工程与技术] 0703[理学-化学] 070301[理学-无机化学] 

基　　金：Supported by the National Natural Science Foundation of China (Grant No. 50476039) Guangdong Provincial Department of Science and Technology (Grant No. 2004A10- 703001) 

主　　题：nanoscale materials heat effect magnetic fluids surface chemistry 

摘      要：The interaction between stabilizers and nanoparticles is one of the important factors to prepare stable magnetic fluids. The magnetic nano-size Fe3O4 core with single domain and the average grain size around 8-12 nm were prepared by chemical precipitation method. The O/Fe molar ratio of the particle surface was measured by X-ray photoelectron spectroscopy (XPS). The heat effects of stabilizers ad- sorption on nanoparticles were measured by solution calorimetry. The excess amount of oxygen was possibly the result of the hydroxygen formed on the surface of the nanoparticles. The heat effects showed that compounds containing carboxyl groups can be adsorbed chemically on magnetite by forming chemical bonds. The other stabilizers involving NH-groups, such as polyethylene-imine, can be adsorbed physically. The exothermic value is about half of the former case.