KSEF R&D Excellence: Application of Light Scattering Techniques to Study Microdroplet Based Processes for Tailored Particles and Thin Films Synthesis

In recent years, tailored microparticles are finding increasing applications in existing and emerging technologies. We propose to examine microdroplet-based processes for synthesis of tailored particles for various applications. In this process, a solution microdroplet undergoes liquid to solid phase transformation. The property of the final solid particle depends on a number of time-dependent physical and chemical transformations occurring in the microdroplet. The mechanisms for controlling structure of the solid phase is not well understood. The maj or reason for this lack of understanding is the difficulty associated with the in situ determination of size, composition distribution and homogeneity during the phase transformation process. A number light scattering techniques developed in our laboratory can be used for in situ physical and chemical characterization of homogeneous and inhomogeneous microdroplets. We propose to experimentally investigate mechanisms for formation of solid phases trom solution microdroplets using high precision light scattering techniques based on optical resonances. Linear streams of highly monodisperse droplets will be used to chart evolution of solid phases in solution droplets with high temporal resolution. Such a system provides a unique space-time relation; thus, by examining droplets at several distances trom the generation point the variation of a droplet with time can be deciphered. The processes that will be investigated include: (i) evaporation of solution microdroplets, (ii) chemical reactions of micro droplets with gas phase reactants, and (iii) photopolymerization of monomer solution droplets. We examine generation of homogenous and layered particles of organic and inorganic materials, microencapsulated particles, and nanoparticles dispersed in polymeric matrix. The objective is to understand the factors that control the morphology (e.g. dimension, porosity and mechanical strength) of the final solid phase with an ultimate aim to develop novel applications of micro droplet-based processes.