Grant: Research Tools and Instruments

We propose to purchase a NANOPIX mini lab-scale Ultra-Small Angle X-ray Scattering (USAXS) system to examine the size, porosity and aggregation behavior of nano-particles. The USAXS technique was implemented for the study of the nanoscale crystalline structure of edible fats by the Marangoni group. A 15-minute analysis of a fat would yield structural information at length scales from 4 nm to 10 um. Both technique and theory developed yielded valuable insight into the structure of these materials and its relationship to functionality. One of the most important parameters derived from this study is the size of a crystalline nanoplatelet (CNP). CNPs can have lengths between 100 nm and 400nm, widths between 60 nm and 100nm and thicknesses between 20 nm and 40nm. CNPs are extremely sensitive to changes in composition, cooling rate and shear. For example, we reported that the tempering process in chocolate led to a 10-fold reduction in CNP size. We have thus developed a structural probe for the nanoscale in these food materials. These experiments had to be carried out at the synchrotron X-Ray facility at Argonne National Labs in Chicago because the required equipment is not available at the University of Guelph. The difficulty in accessing the equipment severely limits the types and number of studies that can be carried out. The NANOPIX machine will allow us to carry out more exploratory studies on the correlation between the processing of fats and oils, their composition and their nanoscale crystalline structure. Defining this correlation is crucial to replace hard fats with oleogels and structured emulsions to improve nutritional properties without affecting functionality and quality. The same approach will be extended to protein gels. The Pensini lab is interested in developing particles with tunable porosity for the targeted delivery of reagents to remediate subsurface contaminants. The Pensini lab is also interested in treating chemical spills on surface waters using emulsion gels stabilized by natural emulsifiers (e.g. soy lecithin, a surfactant-like fat). Emulsion gels must be stable during the time required to decontaminate surface waters. Gel stability is strongly correlated to the structure of the emulsifier films at the oil-water interface and to the aggregation behaviour of the stabilizing species such as surfactant-like fats (e.g. lecithin). The Zhou lab is interested in understanding the size and structure of flocculated proteins, extracellular material and finely dispersed organic matter in water, to optimize the design of advanced filtration membranes for water purification. The size of the contaminant flocs is required to design membranes with the optimal membrane pore size. Also, the porosity of contaminant flocs is correlated with the strength of the flocs. The Zhou lab is interested in using additives to improve floc strength, because strong flocs are less prone to disaggregating when subject to shear in water treatment plants. *