TITLE: "Painting the Town Red: Light Scattering from Concentrated Particulate Dispersions"

SPEAKER: Professor Laurie E. McNeil,

The scattering of electromagnetic radiation by particles is an old and wide-ranging subject, with applications to phenomena such as the blue sky, the obscuration of galaxies by interstellar dust, the curing of photopolymers for stereolithography, the transparency of fishes and the human cornea, and the appearance of reflective display materials, paper, and paint. For single particles of simple shapes, it is possible to calculate the scattering analytically, and if the particles are sufficiently far apart, the scattering is completely described by this analysis. However, in many applications the particle density is sufficiently high or the optical depth is sufficiently large that multiple scattering and near-field interactions among the radiation fields of adjacent particles strongly influence the intensity distribution of the scattered light. In this talk I will present experimental and computational studies of near- and far-field scattering in red and white pigment systems, conducted during my recent sabbatical at DuPont. The results give insights into the microscopic details of scattering from dielectric structures, as well as how to make better red paint for sports cars.