Department of Chemical Engineering, University of Waterloo , 200 University Avenue West, Waterloo, Ontario N2L 3G1, Canada.
Langmuir. 2014 Jan 28;30(3):710-7. doi: 10.1021/la404357j. Epub 2014 Jan 15.
Adsorption-driven self-assembly of nanoparticles at fluid interfaces is a promising bottom-up approach for the preparation of advanced functional materials and devices. Full realization of its potential requires quantitative understanding of the parameters controlling the self-assembly, the structure of nanoparticles at the interface, the barrier properties of the assembly, and the rate of particle attachment. We argue that models of dynamic surface or interfacial tension (DST) appropriate for molecular species break down when the adsorption energy greatly exceeds the mean energy of thermal fluctuations and validate alternative models extending the application of generalized random sequential adsorption theory to nanoparticle adsorption at fluid interfaces. Using a model colloidal system of hydrophobic, charge-stabilized ethyl cellulose nanoparticles at neutral pH, we demonstrate the potential of DST measurements to reveal information on the energy of adsorption, the adsorption rate constant, and the energy of particle-interface interaction at different degrees of nanoparticle coverage of the interface. These findings have significant implications for the quantitative description of nanoparticle adsorption at fluid interfaces.
在流体界面处，纳米粒子的吸附驱动自组装是一种很有前途的自下而上的方法，可用于制备先进的功能材料和器件。要充分发挥其潜力，就需要定量理解控制自组装的参数、界面处纳米粒子的结构、组装的势垒特性以及颗粒附着的速率。我们认为，当吸附能大大超过热涨落的平均能量时，适用于分子物种的动态表面或界面张力 (DST) 模型就会失效，并验证了将广义随机顺序吸附理论应用于胶体颗粒在流体界面吸附的替代模型。我们使用中性 pH 下疏水性、电荷稳定的乙基纤维素纳米粒子的模型胶体体系，证明了 DST 测量有潜力揭示有关吸附能、吸附速率常数以及在界面上不同程度的纳米颗粒覆盖下颗粒-界面相互作用能的信息。这些发现对定量描述胶体颗粒在流体界面处的吸附具有重要意义。
