Aggregation kinetics and cluster structure of amino-PEG covered gold nanoparticles

Abstract

In this study controlled clustering kinetics is demonstrated for PEG grafted gold nanoparticles, in response to applied environmental stimuli; the temperature and ionic strength of the medium. It is also found that the rate of assembly determines the structure of the prepared clusters. After the system is brought out of equilibrium, time-dependent extinction and dynamic light scattering data are used to follow the evolution of nanoparticle cluster formation in real time. The results show that the rate of assembly increases with increasing ionic strength or temperature of the medium. As a result the nanoparticle cluster size scales with ionic strength and temperature, over a cluster size range from a few particle sizes up to the micron-scale. It is found that, even at the lowest ionic strength, the electric double layer repulsion is eliminated; hence the observed differences in kinetics and in cluster structure arise from modulation of the repulsive steric interactions between nanoparticles. The approach should be extendable to suspensions of other nanoparticle types, where the nanoparticle stability is determined by surface-grafted responsive macromolecules.

General nucleation-growth type kinetic models of nanoparticle formation: possibilities of finding analytical solutions

“…In our previous article [25], we showed that the analytical solution of a non-lumped kinetic model is still possible despite the fact that it has an infinite number of concentration variables. The model itself was based on pervious experimental results and theoretical considerations [4,5,[26][27][28][29][30][31]. In the present work, we show that similar analytical solutions can be found in a limited number of other kinetic models as well.…”

“…A general nucleation-growth type kinetic model In this paper, a general class of models for nanoparticle formation will be considered, which is based on previous attempts to build such models and a comparison of experimental results [4,5,[26][27][28][29][30][31]. The model contains three different kinds of steps, two of which represent nucleation, whereas the third one includes particle growth.…”

“…self-cleaning mirrors or coatings or small-scale water purification systems [1][2][3]. A high number of nanoparticle synthesis methods have already been developed [1][2][3][4][5][6][7][8][9][10][11][12], and by now it is clear that the size of a nanoparticle fundamentally influences both its catalytic activity and toxicity. Therefore, controlling the size (and to a lesser extent, the shape) of nanoparticles is of primary importance for the potential applications.…”

A Versatile Route to Assemble Semiconductor Nanoparticles into Functional Aerogels by Means of Trivalent Cations

“…In other words, novel nanoparticle‐based superstructures should combine the properties of the building blocks and the emerging new features that can be achieved solely based on the self‐assembly of the nanocrystals. This challenging task has called numerous assembly procedures into being: triggering the responsive ligand shell, [ 11,12 ] cross‐linking, [ 13,14 ] ligand desorption, [ 15 ] solvent exchange, [ 16 ] controlled solvent evaporation, [ 17 ] applying templates, [ 18 ] or using the cryoaerogelation method. [ 19,20 ]…”

Self-assembly of like-charged nanoparticles into Voronoi diagrams

“…Both understanding and having control of these interactions can help to rationally design higher order structural elements. [6][7][8] Most studies investigate the assembly of nanoscopic building blocks into structures and patterns at the nanoscale or the assembly of nanoparticles and colloids into microstructures (e.g., nanocrystals). 9-18 Solvent evaporation induced self-assembly techniques are also commonly used to prepare assemblies at desired solid substrates with macroscopic dimensions.…”