Surface charge is the electric charge present at an interface. There are many different processes which can lead to a surface being charged, including adsorption of ions, protonation/deprotonation, and the application of an external electric field. Surface charge causes a particle to emit an electric field, which causes particle repulsions and attractions, and is responsible for many colloidal properties.
Surface charge practically always appears on an object surface when it is placed into a fluid. All fluids contain ions, positive (cations) and negative (anions). These ions interact with the object surface. This interaction might lead to the adsorption of some of them on the surface. If the number of adsorbed cations exceeds the number of adsorbed anions, the surface would gain total positive electric charge.
There is another possible mechanism leading to surface charging. It is dissociation of the surface chemical group.
Read more about Surface Charge: Surface Charge Density, Interfacial Potential, Applications of Surface Charge
Other articles related to "surface charge, surfaces, charge, charges, surface":
... Charged surfaces are often useful in creating surfaces that will not adsorb certain molecules (for example, in order to prevent the adsorption of basic proteins, a positively ... groups, which serve to provide a surface charge when submerged in an aqueous solution ...
... Practically all particles in fluids carry a surface charge ... This surface charge is screened with an equally-charged diffuse layer this structure is called the double layer ... of the left hand pole and an excess of positive surface charge at the right hand pole ...
... If the electrode is polarizable, then its surface charge depends on the electrode potential ... IUPAC defines the potential at the point of zero charge as the potential of an electrode (against a defined reference electrode) at which one of the charges ... The potential of zero charge is used for determination of the absolute electrode potential in a given electrolyte ...
... equilibrium”) double layer is the non-electric affinity of charge-determining ions for a surface..." This process leads to the build up of an electric surface ... This surface charge creates an electrostatic field that then affects the ions in the bulk of the liquid ... field, in combination with the thermal motion of the ions, creates a counter charge, and thus screens the electric surface charge ...
... The bound surface charge is the charge piled-up at the surface of the dielectric, given by the dipole moment perpendicular to the surface where s is the separation between the point charges ... Taking infinitesimals and dividing by the differential surface element dS gives the bound surface charge density where P is the polarization density, i.e ... the divergence theorem, the bound volume charge density within the material is hence The negative sign arises due to the opposite signs on the charges in the dipoles ...
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