Modification and characterization of starch nanoparticles

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Latexes are dispersions of polymer particles in water useful in multiple applications such as paints, where they coalesce to form a protective coating on surfaces, or as binders ensuring the adhesion of non-woven fibers constituting paper and paperboard, or as carpet backing, where they provide strength and support for the woven fibers. Polymers latexes are typically produced from petroleum distillates. As oil supplies become scarce and more expensive, the industry is looking for cheaper and greener alternatives to petroleum-based latexes. Ecosphere® is a carbohydrate-based latex prepared by Ecosynthetix from corn or tapioca starch feedstocks. Ecosphere® is thus produced from renewable resources and forms stable emulsions of crosslinked starch particles in water that have already found applications in the paper industry. This proposal aims to expand the understanding and the scope of application of these biolatexes by chemically modifying them, and characterizing the properties imparted the nanoparticles by these modifications. Ecosphere® nanoparticles will be modified by the covalent attachment of either hydrophobic pendants, positively and negatively charged groups, or a combination thereof, and through the attachment (grafting) of linear polymers. The extent of these modifications will be quantified and their influence on the physical properties of the materials obtained will be investigated at the molecular and macroscopic levels with fluorescence and rheology experiments, respectively. Their performance as improved biolatex binders in paper coating applications will be tested. Furthermore the possibility of using modified Ecosphere® as drug delivery vehicles will be explored by monitoring their loading capacity, targeting efficacy, and toxicity to living cells. Together, this set of experiments will provide a comprehensive understanding of the structure-property relationships resulting from the modifications applied to the Ecosphere® nanoparticles.