Kinetics of localized adsorption of colloid particles

Adamczyk, Zbǐgniew; Siwek, Barbara; Zembala, Maria; Weroński, Paweł

doi:10.1021/la00047a007

Cited by 66 publications

(72 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Thus, a particle arriving at the surface is accepted if it does not overlap with a previously adsorbed one; otherwise it is rejected. Specific quantities, such as the maximum coverage of the surface, or jamming limit, are in accordance with some experimental results [3] [4] [5], so it was concluded that RSA was a good model when particles diffuse to the surface. However, further numerical studies which took into account the diffusion showed discrepancies in the pair distribution function [6].…”

supporting

confidence: 77%

Influence of hydrodynamic interactions on the adsorption process of large particles

Pagonabarraga

Rubı́

1994

Phys. Rev. Lett.

View full text Add to dashboard Cite

show abstract

supporting

confidence: 77%

Influence of hydrodynamic interactions on the adsorption process of large particles

Pagonabarraga

Rubı́

1994

Phys. Rev. Lett.

View full text Add to dashboard Cite

show abstract

“…The adsorption of latex spheres onto a flat solid surface is a simple experimental model system, on which considerable work has been done. An optical microscope permits the direct observation of structural properties of the adsorbed layer [11,12]. This apparently simple phenomenon involves several fundamental processes that govern the kinetic behavior of the system and the structure of the adsorbed layer.…”

mentioning

confidence: 99%

mentioning

confidence: 99%

Kinetics of particles adsorption processes driven by diffusion

1997

View full text Add to dashboard Cite

The kinetics of the deposition of colloidal particles onto a solid surface is analytically studied. We take into account both the diffusion of particles from the bulk as well as the geometrical aspects of the layer of adsorbed particles. We derive the first kinetic equation for the coverage of the surface (a generalized Langmuir equation) whose predictions are in agreement with recent simulation results where diffusion of particles from the bulk is explicitly considered. PACS68.10.jY,82.70.Dd,05.70.Ln The adsorption of colloidal particles onto adsorbing surfaces is a very common phenomenon in many fields of Biology and Chemical-Physics. The deposition of bacteria on teeth is an example of such a process. There are many other systems in which suspensions are in contact with adsorbing solid surfaces. The adsorption of latex spheres onto a flat solid surface is a simple experimental model system, on which considerable work has been done. An optical microscope permits the direct observation of structural properties of the adsorbed layer [11,12]. This apparently simple phenomenon involves several fundamental processes that govern the kinetic behavior of the system and the structure of the adsorbed layer. First, the attractive potential that characterize the adsorbing surface plays an essential role. Depending on the strength of this potential, adsorbed particles can either desorb or move laterally or remain irreversibly adsorbed. Second, the kinetics of the adsorption is strongly influenced by particle transport from the bulk to the surface. It depends, for instance, on whether gravity or diffusion dominates the dynamics of the particles in the bulk. Third, the adsorbing particles interact with the adsorbed ones in the vicinity of the surface. This interaction is repulsive for stable colloidal dispersions and, therefore, it is responsible for the saturation of the adsorbing surface, the so-called blocking effect.Theories have been proposed to analyze the contribution of these effects to the kinetics of the adsorption of colloidal particles. A very common model is the random sequential adsorption (RSA) [1], introduced to generate the structure of a layer of irreversibly adsorbed colloidal particles. In this model, the adsorbing particles are deposited sequentially at random. The overlaps are forbiden so that, when in a trial an adsorbing particle overlaps an adsorbed one, this trial is rejected and one proceeds with a new one. Clearly, RSA takes the excluded volume effect into account but it cannot deal with the transport process of the particles from the bulk to the surface. However, a kinetic equation for the RSA model has been proposed [2]. If one defines the coverage of a two-dimensional surface θ as πR 2 ρ s , ρ s being the number of adsorbed particles per unit area, and R the radius of the particles, one then writesHere K a is a kinetic coefficient, ρ B is the concentration in the bulk and Φ RSA (θ) is the available area at a given coverage for a new particle to adsorbe. Φ RSA was first obtained by Widom [3]....

show abstract

“…Its validity for describing adsorption processes is less clear. Although it seems to predict quite accurately the radial distribution function, g(r), of the assembly of the adsorbed particles (6,7), it leads to contradictory results as far as the density fluctuations of adsorbed particles is concerned. This latter is measured by the reduced variance (ratio of variance 2 to mean ͗n͘) of the distribution of the number of particles deposited on a great number of subsurfaces of equal size that are part of the deposition plane (6,8).…”

mentioning

confidence: 99%

Extended random sequential adsorption model of irreversible deposition processes: From simulations to experiments

Lavalle

Schaaf

Ostafin

et al. 1999

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

An experimental study of the irreversible deposition of colloidal particles of various radii R on a solid surface is presented over a wide range of the Péclet number, Pe, or reduced radius R* (Pe ‫؍‬ R* 4 ). The experimental data are analyzed by means of a new generalized random sequential adsorption model that takes explicitly the diffusion of the particles during the deposition into account. It allows description of the continuous transition from a random sequential adsorption-like to a ballistic-like deposition behavior. It depends on three parameters: d s , related to the diffusion of the particles before adhesion; n s , related to the number of allowed adhesion trials of a particle; and R e , representing the effective particle radius. The model allows accounting for all of the experimental observations relative to the radial distribution functions and the number density f luctuations over the whole coverage range and all investigated values of R*. In addition, it is found that d s ͞R is proportional to R* ؊2 as expected for a diffusional process. Moreover, the parameters d s and n s appear to be connected through the empirical relation (d s ͞ R)n s 2͞3 ‫؍‬ C, where C is found to be of the order of 50. This unique statistical model allows an accurate description of the irreversible deposition process, whatever the inf luence of gravity with respect to diffusion.The structure of an assembly of particles deposited or adsorbed on a solid surface depends on the ability of the particles to diffuse along the surface: when they can diffuse on the surface, the laws of statistical mechanics predict the properties of the system. In the case of irreversible deposition processes in which, once adsorbed, the particles can neither move along the surface nor desorb from it, the structure depends on the particle interactions and on a parameter R*, related to the Péclet number by Pe ϭ R* 4 , which characterizes the relative importance of the gravitational field with respect to the Brownian motion of the particles during the deposition process (1). Large values of R* (R* Ͼ 3) correspond to deposition processes in which gravity plays a dominant role, whereas small values of R* (R* Ͻ 1) characterize purely diffusional deposition processes.Over the last few years, our understanding of these irreversible deposition processes has evolved from both the experimental and the theoretical point of view, and a great effort toward modeling has been undertaken. For the case of large R*, the ballistic-deposition (BD) model has been developed (2, 3). It has been shown experimentally that this model describes accurately such deposition processes (4). For the case of small R*, the random sequential adsorption (RSA) model has been introduced (5). Its validity for describing adsorption processes is less clear. Although it seems to predict quite accurately the radial distribution function, g(r), of the assembly of the adsorbed particles (6, 7), it leads to contradictory results as far as the density fluctuations of adsorbed particles is...

show abstract

Kinetics of localized adsorption of colloid particles

Cited by 66 publications

References 0 publications

Influence of hydrodynamic interactions on the adsorption process of large particles

Influence of hydrodynamic interactions on the adsorption process of large particles

Kinetics of particles adsorption processes driven by diffusion

Extended random sequential adsorption model of irreversible deposition processes: From simulations to experiments

Contact Info

Product

Resources

About