Advanced Materials Processing and Analysis Center, Department of Mechanical, Materials and Aerospace Engineering, University of Central Florida, Orlando, Florida 32816, USA.
Langmuir. 2010 May 18;26(10):7188-98. doi: 10.1021/la904285g.
Long-term stability and surface properties of colloidal nanoparticles have significance in many applications. Here, surface charge modified hydrated cerium oxide nanoparticles (CNPs, also known as nanoceria) are synthesized, and their dynamic ion exchange interactions with the surrounding medium are investigated in detail. Time-dependent zeta (zeta) potential (ZP) variations of CNPs are demonstrated as a useful characteristic for optimizing their surface properties. The surface charge reversal of CNPs observed with respect to time, concentration, temperature, and doping is correlated to the surface modification of CNPs in aqueous solution and the ion exchange reaction between the surface protons (H(+)) and the neighboring hydroxyls ions (OH(-)). Using density functional theory (DFT) calculations, we have demonstrated that the adsorption of H(+) ions on the CNP surface is kinetically more favorable while the adsorption of OH(-) ions on CNPs is thermodynamically more favorable. The importance of selecting CNPs with appropriate surface charges and the implications of dynamic surface charge variations are exemplified with applications in microelectronics and biomedical.
胶体纳米粒子的长期稳定性和表面性质在许多应用中具有重要意义。在这里，合成了表面电荷修饰的水合氧化铈纳米粒子（CNP，也称为纳米氧化铈），并详细研究了它们与周围介质的动态离子交换相互作用。CNP 的时变 ζ 电位 (ZP) 变化被证明是优化其表面性质的有用特征。观察到的 CNP 随时间、浓度、温度和掺杂的表面电荷反转与 CNP 在水溶液中的表面修饰以及表面质子 (H(+)) 和相邻羟基离子 (OH(-)) 之间的离子交换反应有关。使用密度泛函理论 (DFT) 计算，我们已经证明，H(+) 离子在 CNP 表面的吸附在动力学上更有利，而 OH(-) 离子在 CNPs 上的吸附在热力学上更有利。选择具有适当表面电荷的 CNP 的重要性以及动态表面电荷变化的影响在微电子学和生物医学中的应用中得到了例证。
