SBIR Phase II: Process Control Sensor for Fine Particles

This Small Business Innovation Research (SBIR) Phase II research project proposes to develop Dynamic Light Scattering (DLS) instruments capable of measuring fine particles in suspensions beyond the limits of current technology. By simultaneous or independent use of three innovative techniques, larger detection aperture, smaller field size, and optical, homodyne amplification, the team can now measure hydrodynamic radius over greater ranges of particle size and concentration than was formerly possible. Two key ideas for this effort are: 1) the construction of a numerical model of the complex phenomenology of DLS with eight free and independent parameters; 2) the ability to apply this new understanding to the quantitative analysis of existing instruments, and to optimize new system designs for extended applications. These ideas have been confirmed empirically, correctly defining operational boundaries, formerly less well understood and quantified. A key advantage is the ability to design DLS systems with superior ranges of performance, versatility, accuracy, and cost, noting especially that deeper understanding improves performance and reduces error limits of reported data. Newly capable and economical instruments are made available for characterizing suspended colloidal particles, from sub-nanometer to micron radii and from almost opaque to almost completely transparent. Extended capabilities include process control of high concentration colloidal materials, common in manufacturing from paint to chemical machining slurries, from foodstuff to pharmaceuticals. At the opposite end of the spectrum of difficultly lie suspensions scattering very little light, such as proteinaceous drugs, fuel cell catalysts, and many other materials of great interest to in-vivo non-invasive measurement of small sample volumes. Aside from a ready market in both real time monitoring and offline analysis for quality control in existing industrial processes, the extended capabilities offer attractive research opportunities into the properties of nanomaterials, a burgeoning field of interest and importance. Such instruments and their enhanced capability will increase materials research opportunities and be economical enough to use in a teaching environment, significantly augmenting the many and complex technologies already used for the assessment of these important materials. In contrast with more invasive measurements that may require dilution or evaporation for sample preparation irrevocably altering what is to be measured, extended DLS techniques complement and may be applied to undisturbed samples as small as a picoliter.