Scaling theory for diffusion-limited cluster aggregation in a porous medium

This presentation deals with the aggregation characteristics of Cu and Ag nanoparticles in presence of starch as the polymer stabilizer. Uncontrolled aggregation of the destabilized nanoparticles offers problem for applications based on surface plasmon activity. Polymer or small molecule surfactants are used to control nature of aggregation of nanoparticles produced by chemical reduction synthesis routes. Different growth models such as diffusion limited cluster aggregation (DLCA), reaction limited cluster aggregation (RLCA) proposed to explain the formation of fractal colloidal aggregates do not account for aggregate formation in presence of polymer or small molecule surfactants. We shall be discussing the role of starch on the aggregation characteristics of copper and silver nanoparticles formed by chemical reduction in aqueous conditions. The effect of NaOH concentration and consequently the pH on such aggregation kinetics during such synthesis is delineated. We use small angle x-ray scattering (SAXS) to quantitatively understand different aspects of aggregation behavior.

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Concentration Influence on Diffusion Limited Cluster Aggregation

MRS Proceedings ◽

10.1557/proc-367-373 ◽

1994 ◽

Vol 367 ◽

Cited By ~ 1

Author(s):

ST.C. Pencea ◽

M. Dumitrascu

Keyword(s):

Brownian Motion ◽

Fractal Dimensions ◽

Simple Random Walk ◽

Two Dimensional ◽

Diffusion Limited Aggregation ◽

Dimensional Lattice ◽

Cluster Aggregation ◽

Box Counting ◽

Diffusion Limited ◽

Diffusion Limited Cluster Aggregation

AbstractDiffusion-limited cluster aggregation has been simulated on a square two dimensional lattice. In order to simulate the brownian motion, we used both the algorithm proposed initially by Kolb et all. and a new algorithm intermediary between a simple random walk and the ballistic model.The simulation was performed for many values of the concentration, from 1 to 50%. By using a box-counting algorithm one has calculated the fractal dimensions of the obtained clusters. Its increasing vs. concentration has been pointed out. The results were compared with those of the classical diffusion-limited aggregation (DLA).

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Switching On and Off the Coffee-Ring Effect in Drying Sessile Nanofluid Droplets

ASME 2013 4th International Conference on Micro/Nanoscale Heat and Mass Transfer ◽

10.1115/mnhmt2013-22190 ◽

2013 ◽

Author(s):

Alexandru Crivoi ◽

Fei Duan

Keyword(s):

Capillary Flow ◽

Three Dimensional ◽

Domain Size ◽

Spherical Cap ◽

Phase Line ◽

Cluster Aggregation ◽

Diffusion Limited ◽

Coffee Ring ◽

Three Phase ◽

Diffusion Limited Cluster Aggregation

The diffusion-limited cluster aggregation (DLCA) model has been implemented in a three-dimensional (3D) domain with a shape of an approximately spherical cap for simulating the drying process of a sessile nanofluid droplet. The droplet evaporation is investigated with the pinned three-phase line, resulting in shrinking contact angle and outward capillary flow. The cluster-cluster aggregation between the particles is taken into account in the model, and the transition from the uniform deposition to the coffee-ring pattern is established by altering the sticking probability parameter. The results of the simulation turn to be consistent with the experimental observation. The influence of the parameters, such as particle volumetric concentration and relative domain size, are studied.

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