Abstract: Nano-ZnO was synthesized by an improved direct precipitation method, followed characterization by both of XRD and TEM. It demonstrates that the diameter of nano particles is 10nm calculated with Scherrer formulate and observed with the photo of TEM. The nano particles were modified with oleic acid, span-60 and sodium laurate, respectively. Macroscopically, the stability of the nano particles was analyzed by the subsidence experiment and discussed the stability of the modified nano-ZnO by the three surfactants. The effect of modification with oleic acid is excellent and the others can not exist in liquid paraffin stably. Microcosmically, the FT-IR spectra indicate that nano particles combine with oleic acid by both types of covalent bond and hydrogen bond to form a singlemolecule layer, but the modification with span-60 and sodium laurate is not stable.

Key words: zinc oxide, surface modification, oleic acid, hydrogen bond