Dušak Peter, Mertelj Alenka, Kralj Slavko, Makovec Darko
Department for Materials Synthesis, Jožef Stefan Institute, Jamova 39, 1000 Ljubljana, Slovenia; Jožef Stefan International Postgraduate School, Jamova 39, 1000 Ljubljana, Slovenia.
Department for Complex Matter, Jožef Stefan Institute, Jamova 39, 1000 Ljubljana, Slovenia.
J Colloid Interface Sci. 2015 Jan 15;438:235-243. doi: 10.1016/j.jcis.2014.09.086. Epub 2014 Oct 13.
Composite particles combining nanoparticles of different functional materials, as well as nanoclusters of nanoparticles of controlled size, can be synthesized by the assembly of nanoparticles in an aqueous suspension. Different interactions between the nanoparticles in the suspension can be applied for their heteroaggregation and controlled by engineering the surface properties of the nanoparticles. The heteroaggregation of nanoparticles in a suspension was studied on a model system composed of superparamagnetic carboxyl-functionalized silica-coated maghemite nanoparticles (cMNPs) (24 nm in size) and larger, amino-functionalized, silica nanoparticles (aSNPs) (92 nm). The heteroaggregates formed with electrostatic attractions between the nanoparticles displaying an opposite electrical surface charge, or with chemical interactions originating from covalent bonding between the molecules at their surfaces. The suspensions were characterized with measurements of the zeta-potential and dynamic light scattering (DLS). The heteroaggregates were analyzed by transmission (TEM) and scanning (SEM) electron microscopy. The kinetics of the heteroaggregation was followed by continuous monitoring of the changes in the average hydrodynamic size by DLS. The results show that covalent bonding is much more effective than attractive electrostatic interactions in terms of a much greater and more homogeneous coverage of the larger central aSNP by the smaller cMNPs in the outer layer.
通过在水悬浮液中组装纳米颗粒，可以合成结合了不同功能材料纳米颗粒以及尺寸可控的纳米颗粒纳米团簇的复合颗粒。悬浮液中纳米颗粒之间的不同相互作用可用于它们的异质聚集，并通过设计纳米颗粒的表面性质来控制。在一个由超顺磁性羧基功能化二氧化硅包覆的磁赤铁矿纳米颗粒（cMNPs）（尺寸为24纳米）和更大的氨基功能化二氧化硅纳米颗粒（aSNPs）（92纳米）组成的模型系统上研究了悬浮液中纳米颗粒的异质聚集。异质聚集体通过纳米颗粒之间显示相反表面电荷的静电吸引力形成，或者通过源自其表面分子间共价键的化学相互作用形成。通过测量zeta电位和动态光散射（DLS）对悬浮液进行表征。通过透射电子显微镜（TEM）和扫描电子显微镜（SEM）对异质聚集体进行分析。通过DLS连续监测平均流体动力学尺寸的变化来跟踪异质聚集的动力学。结果表明，就外层较小的cMNPs对较大的中心aSNP有更大且更均匀的覆盖而言，共价键比有吸引力的静电相互作用更有效。
