What Is Electro-osmosis?
Electroosmosis is one of the electric phenomena. In the electric field, because the porous support adsorbs positive and negative ions in the water, the solution is relatively charged. Under the action of the electric field, the solution moves to a certain direction. This situation is called electroosmosis. For example, when electrophoresis on paper, It absorbs hydroxide ions and is negatively charged, while the aqueous solution in contact with paper is positively charged, which moves the solution toward the negative electrode, and can move particles at the same time when moving, so the performance of particle swimming during electrophoresis is the swimming of the particles themselves Sum of speed and speed of movement carried by electroosmosis.
- Electroosmosis is one of the electric phenomena. In the electric field, because the porous support adsorbs positive and negative ions in the water, the solution is relatively charged. Under the action of the electric field, the solution moves to a certain direction. This situation is called electroosmosis. For example, when electrophoresis on paper, It absorbs hydroxide ions and is negatively charged, while the aqueous solution in contact with paper is positively charged, which moves the solution toward the negative electrode, and can move particles at the same time when moving, so the performance of particle swimming during electrophoresis is the swimming of the particles themselves Sum of speed and speed of movement carried by electroosmosis.
Electroosmotic electrokinetic phenomenon
- The velocity of liquid movement per unit field strength is called the electroosmotic velocity. The electroosmotic velocity of a liquid is simply proportional to the potential between the solid and liquid phases. Therefore, electroosmosis can be used to measure the potential, but this method is limited to materials that can form capillary or porous media. Electroosmosis technology is commonly used in industry, [1] to enhance fluid mixing in microchannels, [2] to drive out moisture in products, to prepare porous media materials, [3] to control the movement of liquid films in biochips, and other practical applications.
Numerical simulation method of electroosmosis
- The simulation of the electroosmotic process involves a flow equation (Navier-Stokes equation) describing fluid motion, an equation (such as Poisson-Boltzmann equation) describing electric potential and charge (electron or charged particle), and a transport equation describing ion / charged particle motion. .
- For example, an electroosmotic micromixer using COMSOL Multiphysics simulation,
- The geometric model is shown in the figure,
- >> Two fluids enter from the left end, laminar inlet
- >> Alternating electric field is applied, change according to sine curve, V0 and frequency are the same, electrode polarity changes alternately
- Simulation results: