Research On Particle Size Measurement Of Submicron Particles Based On Polarized Light Scattering

With the wide application of submicron particles in materials,chemical andother fields,the particle size detection technology is becoming more and more important,among which the particle size detection technology based on polarized light scattering has become the research focus of scholars at home and abroad because of its high measurement accuracy,strong stability,real-time detection and other characteristics.In this paper,a submicron particle size measurement system is designed based on Mie scattering principle and polarization scattering characteristics of submicron particles.The main research contents are as follows:1.Based on Mie scattering theory and polarization scattering characteristics of submicron particles,the polarization scattering intensity difference characteristics of submicron particles with different sizes under vertical/horizontal polarized light irradiation are studied.The theoretical polarization difference energy distribution of submicron particles with multiple sizes was obtained by software simulation.By analyzing the characteristics of multi-group simulation curves at large angles,the feasibility of differentiating different submicron particle sizes by polarization difference energy distribution is verified.2.The submicron particle size detection system is designed,which consists of optical path system,sample module,photoelectric detection unit and data analysis software.A single linearly polarized He-Ne laser equipped with a half-wave plate provides two groups of incident light with vertical polarization and horizontal polarization for the experimental system.The incident light irradiates the sample pool with oblique incidence to reduce the influence of total reflection on the accurate measurement of scattered light energy.The photoelectric detection unit is composed of a turntable combined with a single photomultiplier tube to realize multi-angle and large range light energy distribution detection.The resolution of light energy distribution is improved and the structure of particle size measurement system is simplified.Finally,a data analysis software is designed to control the collection of polarized scattered light energy distribution,and data preprocessing and submicron particle size distribution inversion algorithm are integrated,which can process,store and display the collected and calculated data and improve the operability of the system.3.The influence factors of the inaccuracy of particle size measurement are analyzed,including the scattering Angle deviation caused by oblique incidence and the background noise generated by the system structure.To offset the scattering Angle,the scattering Angle correction was realized by establishing the relationship between the detector rotation Angle and the scattering Angle.The goodness of fit R~2between the release of polarized light and the theoretical value of 350 nm,200 nm and 100 nm standard samples after correction was calculated as 0.94517,0.96823 and 0.97241,respectively.The causes of background noise are analyzed and studied.The influence of background noise on the measurement of light energy distribution is eliminated to a large extent by subtracting the light energy distribution without sample.4.Based on Mie scattering mathematical model,the scattering coefficient matrix of polarization difference light energy was calculated,and the particle size distribution was obtained by inversion of polarization difference light energy distribution of submicron particles by Chahine algorithm.The particle size measurement results of 350 nm,200 nm and 100 nm submicron standard samples show that the peak location of particle size distribution is accurate and the width coefficients are 0.15,0.25 and 0.66,respectively.The cumulative particle size distribution curves are consistent with the theoretical analysis.Multiple groups of submicron particle size distribution data were obtained through repetitive experiments,and the relative standard deviations of data were calculated.The most representative D50 relative standard deviations were 1.95%,2.34%and 2.79%,respectively,which were all less than the international standard value of 3%.In conclusion,the particle size detection system designed in this paper can accurately measure the particle size of submicron particles,and the repeatable experimental data meet international standards.