Nanoparticle sizing for poly-dispersed particles using Nanoparticle chip

Abstract

For poly-dispersed nanoparticles, which have more than two peaks on their particle size distribution (PSD), it is important to determine the mean particle diameter and their dispersion at each peak in a liquid. Dynamic Light Scattering (DLS), that is one of a typical nanoparticle sizing method, has difficulty to determine the several peaks in the PSD for the poly-dispersed particles. On the other hand, Image analysis methods (IA) can distinguish the peak for both the primary particle and secondary particle in the PSD of poly-dispersed particles accurately. However, IA is a time-consuming method and it is difficult to apply the measurement of the PSD due to the requirement of measuring the large number of particles, one by one. The particles in the liquid are transferred to a substrate in air when observing the particle to measure their size and the size distribution. In this procedure, some particles usually aggregate with surrounding particles. It causes the difference between the PSD for dispersed particles in liquid and that of the particles on the substrate. In this study, we suggest a novel particle sizing method using “Nanoparticle chip”, that is nanoparticles grid on the substrate to maintain the poly-dispersed condition in the liquid, to develop IA for measuring the poly-dispersed particles in liquid. The dispersed condition of the particle on Nanoparticle chip can be kept from the condition in liquid when the particles are transferred to the substrate in air. Therefore, measuring the PSD on Nanoparticle chip is equal to measure the PSD in the liquid. In this paper, in order to verify the feasibility of the nanoparticle sizing using Nanoparticle chip to measure the PSD for poly-dispersed particles in the liquid, we performed a fundamental experiment to fabricate the Nanoparticle chip and to determine the PSD for poly-dispersed particles. In this report, it is reported that the PSD for the poly-dispersed particles, which is the mixture of 152nm particle and 498nm particle, using Nanoparticle chip.

Keywords

• nanoparticle sizing
• nanoparticle chip
• geometric diameter
• image analysis
• dynamic light scattering (dls)
• primary particle
• secondary particle
• particle size distribuiton
• aggregation