Characterization Of Movement Of Magnetic Particles In Aqueous Solution

Currently, due to the unique nature，magnetic microsphere has becomea research focus. The environment of applications of magnetic microspherewas most in liquid solution. The characteristic in liquid solution was keyindicator for application. This paper studied the magnetic microspheresfrom the perspective of aqueous phase movement.This paper measured transmittance of magnetic microspheres at the570nm, and then converted into turbidity curve to track movement ofmagnetic microspheres. A stress model of magnetic microspheres wasproposed via the analysis of magnetic microspheres. With Monte Carlomethod of a large number of particles, simulation of magnetic field and lightscattering calculation, Least-squares fitting method was used to fittingturbidity curve. The best fitting gave the movement-associated parametersof magnetic microspheres. With this procedure, the physical size andmagnetization of magnetic microspheres were estimated.When using this model to analyze the transmittance and determineparameters related to aqueous phase movement of magnetic microspheres,the fitting did not converge, but there was clear covariance betweenphysical size and magnetization. So we used least-squares fitting to get the local best fitting results of physical size and magnetization, and then toestablish an association function for such physical sizes and magnetizationachieving local best fitting. Global optimal solution of physical size andmagnetization was achieved for each curve when this association functionof physical sizes and magnetization was applied for iterative fitting.With this analysis method, physical sizes and magnetization asestimated were consistent with others methods as routinely determined; afew particles had some deviation and needed further analyses. By thisprocess, we figured out the physical size and magnetization of magneticmicrospheres which correlated with its movement in aqueous phase. Thisprocess can be used to characterize magnetic microspheres, and had veryimportant significance in guide the production of magnetic microspheres.