During this Phase II SBIR development program, Tetramer Technologies will develop highlymonodisperse 100-nm and sub-100-nm diameter nanoparticles for use as latex size standards. Highlymonodisperse nanoparticle latexes are needed for improved calibration of electron microscopes, lightscatteringparticle sizing instruments, atomic force microscopes, and particle counters/contamination monitors used in the semiconductor industry. Current commercial latex standard size distributions are too broad to provide the required resolution for the calibration of these systems. During Phase I, Tetramer synthesized highly-monodisperse 100-nm nanoparticles with less than 2 nm size variation and demonstrated the ability to tune the size below 100 nm, however, the sub-100-nm syntheses were not optimized. Building on the Phase I success, Tetramer will develop reproducible synthetic methods to produce highly-monodisperse sub-100-nm nanoparticles, study the stability of the produced latexes, and scale-up the process to commercially viable levels. Initially, Tetramer will develop a synthetic method to reproducibly deliver sub-100-nm nanoparticles with controlled sizes. Subsequently, Tetramer will investigate methods to produce narrower size distributions, analyzing the samples with both dynamic light scattering and scanning electron microscopy. Nanoparticles will be analyzed to determine their long-term stability as latex solutions. Finally, Tetramer will scale-up the synthetic and purification procedures and begin sampling materials to commercial partners.