Jerzy Haber Institute of Catalysis and Surface Chemistry , Polish Academy of Sciences , Niezapominajek 8 , PL-30239 Krakow , Poland.
Langmuir. 2018 Jul 24;34(29):8489-8498. doi: 10.1021/acs.langmuir.8b01491. Epub 2018 Jul 16.
Formation of positively charged gold nanoparticle layers on polystyrene microparticles (PSMs600) was studied using the electrokinetic and the concentration depletion methods based on atomic force microscopy (AFM) and scanning electron microscopy (SEM) imaging. Primarily, the dependence of electrophoretic mobility of microparticles on the gold nanoparticle concentration in the suspension was measured. These results were quantitatively interpreted in terms of the three-dimensional electrokinetic model. This allowed to derive a formula for calculating the coverage of nanoparticles under in situ conditions whose validity was confirmed by direct SEM imaging of deposited gold nanoparticles (AuNPs). Additionally, the maximum coverage of gold nanoparticles for various ionic strengths was determined using a concentration depletion method based on AFM imaging of residual particles deposited on the silica substrate. The maximum coverage increased with ionic strength attaining a value of 0.35 for the ionic strength of 3 × 10 M. This effect was attributed to the decreasing range of lateral electrostatic interactions among deposited particles. The electrokinetic properties of the gold nanoparticle layers were also evaluated in pH cycling experiments that confirmed their stability. Beyond significance to basic science, the new data acquired in this work confirm the feasibility of preparing gold nanoparticle layers on polymer microparticles characterized by a controlled structure, coverage, and electrokinetic properties.
使用基于原子力显微镜（AFM）和扫描电子显微镜（SEM）成像的电动和浓度耗竭方法研究了带正电荷的金纳米粒子层在聚苯乙烯微球（PSMs600）上的形成。首先，测量了微球的电泳迁移率随悬浮液中金纳米粒子浓度的依赖性。这些结果根据三维电动模型进行了定量解释。这允许推导出一个用于计算原位条件下纳米粒子覆盖率的公式，该公式的有效性通过直接对沉积的金纳米粒子（AuNPs）进行 SEM 成像得到了验证。此外，使用基于 AFM 成像的残留粒子在二氧化硅基底上沉积的浓度耗竭方法，确定了各种离子强度下金纳米粒子的最大覆盖率。最大覆盖率随离子强度的增加而增加，在 3×10 M 的离子强度下达到 0.35 的值。这种效应归因于沉积粒子之间的横向静电相互作用范围减小。在 pH 循环实验中还评估了金纳米粒子层的电动性质，这些实验证实了它们的稳定性。除了对基础科学具有重要意义外，这项工作中获得的新数据还证实了在具有受控结构、覆盖率和电动性质的聚合物微球上制备金纳米粒子层的可行性。
