Abstract：In order to determine whether the surface effect affect the measurement result of dynamic light scattering or not, a width adjustable sample cell was designed, and measurements of standard particles based on a dynamic light scattering system with high-speed linear CCD was performed. The results show that when the sample cell width is less than 1.3 mm, the measured particle size increase linearly with the decrease of the width. As the width reduces to 0.6 mm, the difference between the measured values and that in the free space can be more than 5%. This demonstrates that the sample cell width affects Brownian motion of particles obviously. Hence, the measured results of dynamic light scattering using micor-cell should be corrected accordingly.

Keywords: dynamic light scattering; nanoparticle size measurement; micro-cell; surface effect