CONICET | Buscador de Institutos y Recursos Humanos

In this work a light scattering apparatus developed to study heterogeneous liquid systems of evolving morphology is presented. A Fraunhofer configuration consisting of a linear array of photodiodes is used to detect the light scattered by thin samples illuminated by a He-Ne laser light. Temperature control is available. The instrument is tested with the polymerization induced phase separation of a thermosetting polymer formulated with a divinylester resin copolymerized with styrene and modified with poly(methylmethacrylate). The system is successfully modeled as an arrangement of particles growing in size and number, and varying in composition. The aptitude of the experimental setup to provide results that can be quantitatively analyzed is checked using polystyrene microspheres standards. Different samples of nominal sizes of 0.5, 1 and 2 µm are used in different combinations of sample thickness and concentration. The analysis of the light scattering spectra is performed using inverse techniques to estimate the particle size distribution of the microspheres. The results agree with the previous knowledge on the parameters of the samples.