Performing Small Angle X-ray Scattering (SAXS) on Polystyrene Probes and Polysaccharide Microgels

Small angle x-ray scattering (SAXS) is a scattering technique that can be used to determine the average size, shape, and internal structure of nanoparticles in solution. Visible light scattering can also be used to determine size and shape distributions, but SAXS provides a wider q-range and ability to probe internal structures. The higher q-range also allows examination of smaller particles and portions of large particles. Unlike visible light scattering, SAXS yields information on the internal structure of particles as X-rays penetrate many non-transparent materials and have enough resolution to probe small structural elements. This project is focused on SAXS measurements of polystyrene spherical standards of various sizes (24-450 nm in diameter) with eventual goal of applying it to similarly sized polysaccharide microgels. Here we present the results obtained from SAXS measurements at Kent State University using the Xenocs Xeuss 3.0 system using a procedure developed by us. Our SAXS results on polystyrene hard spheres generally agree their specs. Our initial microgel results are much more tentative. Moving forward, we plan to expand our microgel runs applying the vast experience of SAXS on polystyrene probes with hopes to gain some information on the internal structure of the microgels.