September 28, 2020
Way to control the interaction of microparticles in differently rotating electric and magnetic fields
Bauman Moscow state technical University has proposed a way to control the interaction of microparticles in differently rotating electric and magnetic fields. The results of the research will help to create technologies for the synthesis of materials with the specified properties. An article describing the work was published by the scientific journal Soft Matter.
It turned out that for certain rotation parameters, the fields describing a curve on the surface of a cone, cylinder, or ellipsoid lead to the same interactions of particles in the horizontal plane. The research will help to create technologies for the synthesis of new materials with specified properties based on the phenomenon of controlled self-organization in soft matter.
If an external electric or magnetic field is applied to particles floating in a liquid, they begin to interact with each other. However, if the external field rotates rapidly in space (much faster than the particles move in solution), they can be controlled. For example, you can get them to get closer or distance from each other. Thus, rotating magnetic and electric fields can be used, for example, for self-Assembly of new materials in solutions.
MSTU scientists calculated on a computer how spherical microparticles will behave in differently rotating electric and magnetic fields. For example, fields can rotate by describing curves in space that lie on certain geometric surfaces: a plane, a cone, a cylinder, and an ellipsoid. For the calculation, the researchers used colloidal particles of silicon dioxide in an electric field and particles of iron oxide in a magnetic field.
It turned out that in cases with a cone, cylinder, and ellipsoid, the interactions can be brought together. Moreover, you can create special field curves in which particles interact with their neighbors in the same way in all directions. In this case, the characteristics of these curves can be changed so that the particles either attract each other, or repel and move away from each other in different ways in the horizontal and vertical planes. For each specific case, as the researchers found out, it is possible to choose the right type of particle interaction.
"It was unexpected for us that such complex and different configurations of external fields are directly interconnected. We can construct interactions between particles using complex spatially rotating fields. The magic parameters we found make it possible to study controlled self – Assembly and self-organization in three-dimensional materials, and not just in a monolayer," said Stanislav Yurchenko, one of the authors of the study.