Interaction of fatty acid monolayers with cobalt nanoparticles
Interaction of fatty acid monolayers with cobalt nanoparticles
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DOI：
10.1021/nl035139x
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发表时间：
2004-02-01
期刊：
影响因子：
10.8
通讯作者：
Dravid, VP
中科院分区：
文献类型：
--
作者：
Wu, NQ;Fu, L;Dravid, VP
由于货车范德华力和磁偶极相互作用，磁性纳米颗粒的稳定胶体悬浮具有挑战性。因此，在化学合成过程中用表面活性剂包覆磁性纳米颗粒以制备分散良好的纳米颗粒胶体是必要的。在本研究中，以脂肪酸（油酸）为表面活性剂，合成了尺寸约为15 nm的钴纳米粒子。利用傅里叶变换红外光谱（FTIR）和X射线光电子能谱（XPS）研究了表面活性剂与Co纳米粒子的化学作用。结果表明，油酸以羧酸盐形式吸附在Co纳米粒子表面，羧酸盐中的两个氧原子与Co原子对称配位，形成共价Co-O键。这一结果表明表面活性剂与Co纳米粒子之间存在较强的相互作用，从而增强了Co胶体的稳定性。
Stable colloidal suspension of magnetic nanoparticles is challenging owing to both van der Waals forces and magnetic dipolar interactions. Thus, it is essential to coat magnetic nanoparticles with a surfactant during chemical synthesis in order to prepare well-dispersed nanoparticle colloid. In the present study, cobalt nanoparticles (similar to15 nm in size) were synthesized with the fatty acid (oleic acid) as a surfactant. The chemical interaction of the surfactant with the Co nanoparticles was studied by using Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). The results indicated that oleic acid gets chemisorbed as a carboxylate on the Co nanoparticle surfaces, and the two oxygen atoms in the carboxylate are coordinated symmetrically to the Co atoms, leading to the formation of the covalent Co-O bond. This result has implications for the strong interaction between the surfactant and Co nanoparticle, which enhances the stability of Co colloid.