Dynamic scaling in colloidal fractal aggregation: Influence of particle surface charge density

Author(s):  
A. Fernández-Barbero ◽  
M. Cabrerizo-Vílchez ◽  
R. Martínez-García
1996 ◽  
Vol 53 (5) ◽  
pp. 4981-4989 ◽  
Author(s):  
A. Fernández-Barbero ◽  
M. Cabrerizo-Vílchez ◽  
R. Martínez-García ◽  
R. Hidalgo-Álvarez

2016 ◽  
Vol 186 ◽  
pp. 419-434 ◽  
Author(s):  
Venkateshwar Rao Dugyala ◽  
Thiriveni G. Anjali ◽  
Siliveru Upendar ◽  
Ethayaraja Mani ◽  
Madivala G. Basavaraj

In this contribution, we discuss the role of surface charge on the adsorption of shape anisotropic particles to fluid–fluid interfaces in the context of their application in particle-stabilized emulsions. Starting with a pendent aqueous drop containing nano-ellipsoids of known surface charge density suspended in an oil medium, we study the kinetics of adsorption of the ellipsoids to the water–decane interface using pendant drop tensiometry. The interfacial tension of the drop is recorded as a function of time by analyzing the shape of the drop. We show that the particles that are weakly charged readily adsorb to the water–decane interface and the adsorption behavior is influenced by the particle surface charge density. Furthermore, as the area available for the particles deposited at the interface is reduced, the interface populated with self-assembled ellipsoids shows wrinkles indicating buckling of the particle-laden interface under compression. However, the buckling is not observed if nano-ellipsoids are highly charged confirming that the particles do not adsorb to the interface when they are highly charged. This suggests that in several examples where the particles at interfaces concept is exploited, the repulsive energy barrier due to the particle surface charge plays a key role in the adsorption of particles to the interfaces. However, once the particles are adsorbed, the interfacial properties of the monolayer depend on the particle–particle interactions. Thus a combination of these interactions determines the concentration of particles at the interface, their microstructure and interfacial properties. The effect of these interactions on the quantity and size of the emulsion drops stabilized by ellipsoidal particles is also explored.


1950 ◽  
Vol 34 (2) ◽  
pp. 183-192 ◽  
Author(s):  
H. B. Williams ◽  
A. R. Choppin

1. Adsorption of ovalbumin on the latex surface was in excess of the quantity required to produce coverage of the surface over most of the protein concentrations range which was investigated. 2. "S" shaped isothermals which probably indicated multilayer adsorption were obtained. 3. The quantity of ovalbumin required to produce a constant surface charge density on the latex particle surface was a function of the pH, and a theory of active centers on the latex particles has been suggested. 4. A shift in the isoelectric point from that of native ovalbumin has been observed for the protein when adsorbed on a synthetic latex.


Cells ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 1519
Author(s):  
Leixin Ouyang ◽  
Rubia Shaik ◽  
Ruiting Xu ◽  
Ge Zhang ◽  
Jiang Zhe

Many bio-functions of cells can be regulated by their surface charge characteristics. Mapping surface charge density in a single cell’s surface is vital to advance the understanding of cell behaviors. This article demonstrates a method of cell surface charge mapping via electrostatic cell–nanoparticle (NP) interactions. Fluorescent nanoparticles (NPs) were used as the marker to investigate single cells’ surface charge distribution. The nanoparticles with opposite charges were electrostatically bonded to the cell surface; a stack of fluorescence distribution on a cell’s surface at a series of vertical distances was imaged and analyzed. By establishing a relationship between fluorescent light intensity and number of nanoparticles, cells’ surface charge distribution was quantified from the fluorescence distribution. Two types of cells, human umbilical vein endothelial cells (HUVECs) and HeLa cells, were tested. From the measured surface charge density of a group of single cells, the average zeta potentials of the two types of cells were obtained, which are in good agreement with the standard electrophoretic light scattering measurement. This method can be used for rapid surface charge mapping of single particles or cells, and can advance cell-surface-charge characterization applications in many biomedical fields.


Author(s):  
Linards Lapčinskis ◽  
Artis Linarts ◽  
Kaspars Mālnieks ◽  
Hyunseung Kim ◽  
Kristaps Rubenis ◽  
...  

In this study, we investigate triboelectrification in polymer-based nanocomposites using identical polymer matrixes containing different concentrations of nanoparticles (NPs). The triboelectric surface charge density on polymer layers increased as the...


2021 ◽  
Vol 22 (5) ◽  
pp. 2270
Author(s):  
Joanna Kotyńska ◽  
Monika Naumowicz

Interactions between phospholipid membranes and selected drugs affecting the central nervous system (CNS) were investigated. Small, unilamellar liposomes were used as biomimetic cell membrane models. Microelectrophoretic experiments on two-component liposomes were performed using the electrophoretic light scattering technique (ELS). The effect of both positively (perphenazine, PF) and negatively (barbituric acid, BA) charged drugs on zwitterionic L-α-phosphatidylcholine (PC) membranes were analyzed. Experimental membrane surface charge density (d) data were determined as a function of pH. Quantitative descriptions of the adsorption equilibria formed due to the binding of solution ions to analyzed two-component membranes are presented. Binding constants of the solution ions with perphenazine and barbituric acid-modified membranes were determined. The results of our research show that both charged drugs change surface charge density values of phosphatidylcholine membranes. It can be concluded that perphenazine and barbituric acid are located near the membrane surface, interacting electrostatically with phosphatidylcholine polar heads.


2020 ◽  
Vol 22 (35) ◽  
pp. 20123-20142
Author(s):  
Hadi Saboorian-Jooybari ◽  
Zhangxin Chen

This research work is directed at development of accurate physics-based formulas for quantification of curvature-dependence of surface potential, surface charge density, and total surface charge for cylindrical and spherical charged particles immersed in a symmetrical electrolyte solution.


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