Diffusional Deposition of Charged Latex Particles on Water−Solid Interfaces at Low Ionic Strength

Abstract

The deposition of positively charged latex particles with radii between 20 and 100 nm on a negatively charged mica surface is investigated with atomic force microscopy at low ionic strengths. The polystyrene latex spheres with amidine headgroups are characterized as to their size distribution, electrophoretic mobility, and aggregation behavior. Surface coverage measurements take into account the polydispersity of the particles on the surface. Deposition kinetics from a quiescent solution are, for low coverage, in good agreement with diffusion-limited adsorption. At long times, the surface coverage tends toward a maximum surface coverage θmax independent of the particle concentration but depending on ionic strength. This work extends the available data for θmax for small particle size and very low ionic strengths. The values for θmax decrease with decreasing ionic strength; this trend is described with a simple model based on random sequential adsorption and the effect of overlapping double layers. Particle size polydispersity can modify the results for θmax substantially; its influence is investigated in detail.

Diffusion Sampler for Measurement of Acidic Ultrafine Particles in the Atmosphere

“…Additional deposition of the larger particles is inertia impaction (Cohen et al 1990). Electrostatic forces may have an effect on the enhanced deposition of smaller particles (Elimelech and O'Meliat 1990;Semmler et al 1998). In the present experimental calibration, the impact of the particle charge should be minor because the PSL particles used for calibration were electrically neutral particles and electrostatic forces might not be important since the plates making up the DS were metal.…”

Coupled Influence of Colloidal and Hydrodynamic Interactions on the RSA Dynamic Blocking Function for Particle Deposition onto Packed Spherical Collectors

“…Several theoretical approaches have been proposed to assess the influence of electrostatic repulsion on the extent of surface coverage (37)(38)(39)(40). Here, we attempt to relate the observed experimental behavior with two of these approaches.…”

Micro- and Nanopatterning of Surfaces Employing Self Assembly of Nanoparticles and Its Application in Biotechnology and Biomedical Engineering

“…(Antelmi & Spalla 1999) with sapphire substrates and by Semmler et.al. with mica substrates (Semmler, Mann et al 1998). At the point of zero surface charge density (PZC) no particle adsorption was observed.…”

“…Capillary forces (Fig.1a) act on particles as a result of the surface tension between the solvent and the particle material (Denkov, Velev et al 1992;Kralchevsky & Denkov 2001). After application of a droplet of a particle suspension onto a substrate (Denkov, Velev et al 1992;Burmeister, Schäfle et al 1997;Burmeister, Badowsky et al 1999), during the controlled withdrawal of a sample from a particle suspension (Choi, Jang et al 2004;Prevo & Velev 2004), during spin coating (Denis, Hanarp et al 2002;Choi, Jang et al 2004;Jiang & McFarland 2004) or after adsorption of particles to a substrate in a particle suspension (Semmler, Mann et al 1998;Serizawa, Takeshita et al 1998;Antelmi & Spalla 1999;Serizawa, Kamimura et al 2000;Hanarp, Sutherland et al 2003) the evaporation of the solvent plays a critical role with respect to the structure of the particle layer. As the thickness of the solvent layer becomes comparable to the particle diameter, attractive forces arise pulling particles together to form 2D crystals.…”

“…In order to induce particle adhesion, particles and substrate surface have to bear opposite charges. In case of the substrate this has been achieved by choice of an appropriate material such as an oxide or mica (Semmler, Mann et al 1998;Antelmi & Spalla 1999) or by deposition of synthetic or biological polyelectrolyte mono-or multilayer coatings (Serizawa, Takeshita et al 1998;Serizawa, Kamimura et al 2000;Lohmüller, Müller et al 2008), which can be deposited under well controlled conditions yielding reproducible results. The charge density of such a polymer layer can be tuned within a certain range by the choice of the salt concentration of the polymer solution during deposition.…”