Universal diffusion-limited colloid aggregation

Abstract

We study the process of diffusion-limited colloid aggregation (DLCA) using both static and dynamic light scattering. Static light scattering is used to measure the fractal dimension of the clusters as well as their structure factor, which is found to be in good agreement with that obtained from calculation using computer-generated clusters. Dynamic light scattering is used to probe both translational and rotational diffusion motion of the clusters. A method to separate their respective contributions is developed, allowing a quantitative determination of the average hydrodynamic radius. In addition, we determine the ratio of the hydrodynamic radius to the radius of gyration for individual aggregates, and find / 3 = 0.93. A method is developed to scale all the dynamic light scattering data onto a single master curve, whose shape is sensitive to key features of the DLCA process. Good agreement is found between our prediction of the shape of the master curve and that obtained from experiments. Using several completely different colloids, we find that the shape of their master curves are identical, their fractal dimensions are identical and their aggregation kinetics are identical. This provides strong evidence of the universality of the DLCA regime of colloid aggregation.

Interaction of metal oxide nanoparticles with lung surfactant protein A

“…The evaluation of the AUC raw data incorporated the fractal morphology of nanoparticle agglomerates and applied the fractional dimension of 2.1 together with the sedimentation relation as specified in Eq. (6) of the reference [58]. This value of the fractional dimension has been shown to be universal for all reaction-limited colloid agglomerates [58,59].…”

“…(6) of the reference [58]. This value of the fractional dimension has been shown to be universal for all reaction-limited colloid agglomerates [58,59]. The tabulated material's constant of refractive index allows the interference optics to linearly direct quantify the fraction that is dispersed to diameters below 100 nm in the actual test preparation, with the full size distributions shown in the integrated Table in Figure 3.…”

Fractal Analysis of Aggregates Formed by Heating Dilute BSA Solutions Using Light Scattering Methods

“…This method is simple, however, at a later stage in the aggregation so that the I(q) is entirely dominated by aggregates of qR~ > 1, satisfactory extrapolation is difficult due to the polydispersity effect. 16 …”

Simulated Reversible Aggregation Processes for Different Interparticle Potentials: The Cluster Aging Phenomenon

“…8,35 Considering that the cluster fractal dimension for RLCA (d f RLCA ) 2.10 ( 0.05) is also very close to the one obtained for this reversible regime, a detailed study of the cluster size distribution becomes very convenient as a general practice for discerning between both situations. [14][15][16] 4.3. Breakable Primary and Secondary Bonds.…”