Scattering properties of rutile pigments located eccentrically within microvoids

We study the optical properties of opaque polymer pigmented coatings. The system consists of spherical rutile particles encapsulated in spherical microvoids embedded in a transparent polymer resin, The single-scattering properties of this system have been analyzed already, in case the rutile particle is located at the center of the microvoid. Here, we use a T-matrix approach to generalize and extend this analysis to the more realistic case when the rutile particles is located off-center within the microvoid. We also consider the multiple-scattering effects of a cluster composed by a collection of air bubbles with off-center rutile inclusions. Our calculations take into account the multiple scattering and the dependent-scattering processes of each pigment particle of the aggregate, using a new recursive T-matrix algorithm. (C) 2001 Elsevier Science Ltd. All rights reserved.