Our goal is to develop combinatorial and high-throughput measurement approaches for rapid characterization of the structure and phase behavior of multicomponent fluid mixtures, as needed to advance the development of polymer-based formulations. Our approaches, which leverage microfluidic "lab on a chip" concepts, help industry discover, develop, and understand the complex fluids that are the basis of formulations, including paints, coatings, adhesives, pharmaceuticals, and personal care products.
Additional Technical Details
Polymer additives in formulations such as coatings, personal care goods, and pharmaceuticals can enhance key performance properties, but optimization of these components requires means to measure critical structure-property relationships over vast multivariate spaces.
Building on our earlier work, this microfluidic system has a built-in dynamic light scattering (DLS) probe. This fiber- based detector enables rapid and nanometer precision measurement of the size and dispersion of polymer aggregates in solution. Accordingly, it is a highly powerful tool for determining whether the library of polymer molecules synthesized on the device form structures such as nanoscale micelles for drug delivery or monodisperse latex nanoparticles.
We demonstrated the power and operation of our integrated microfluidic device by having it synthesize a series of styrene-b- methacrylate block copolymer surfactants. The polymer library varied the composition and length of the methacrylate block. Subsequent addition of dodecane reduced the solvent quality for the styrene block, inducing the formation of nanoscopic micelles, but in some cases larger micrometer-sized aggregates (see below). The online DLS probe was able to map these solution behaviors over the library variables and determine optimal molecular parameters for micelle formation.
We reported this work via invited lectures at FY07 national meetings of the American Chemical Society and the Materials Research Society, and at two NIST Combinatorial Methods Center industry member workshops. In FY08, we will extend and employ this integrated DLS strategy to measure the behavior of specialty surfactants through processing routes that vary temperature and composition.