(328r) A Comparison of Atomic Force Microscopy (Afm) and Dynamic Light Scattering (Dls) Methods to Characterize Nanoparticle Size Distributions

This paper compares the capabilities of dynamic light scattering (DLS) analysis and atomic force microscopy (AFM) analysis for characterizing size distributions of various nanoparticle mixture in the size range of 1 ? 100 nm. The bimodal system of polymer nanospheres, three-modal mixture of colloidal gold and CdTe quantum dots were characterized by both techniques. Average DLS values for mono-size dispersed particles of polymer and gold are slightly higher than the nominal values where AFM values were slightly lower than the nominal values. Bimodal and three-modal distributions were easily identified with AFM, but DLS results were skewed toward larger particles. AFM average particle size for mono-size dispersed particles of CdTe quantum dot is in a good agreement with the nominal values, while average DLS values were found to be erroneous. AFM characterization of nanoparticles using automated analysis software provides an accurate and rapid analysis for nanoparticle characterization.