Solid and colloidal particles via sonochemistry

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Time-efficient and inexpensive synthetic routes to manufacture engineered solids and colloidal particles are required by the ever-changing market and applications. The long term objective is to develop ultrasound (ULS)-based techniques to manufacture far-ranging materials, including inorganic, organic, composite and hybrid matrices. I anticipate that modulating the local temperature and pressure, and micro-turbulence enacted by ultrasonic acoustic cavitation will fine-tune the structural-morphological properties of solid and colloidal particles, being these inorganic, organic or hybrid. The sub-objectives include: i) Sonochemical synthesis of catalysts for liquid-solid and gas-solid systems, ii) Sonochemical sol-gel and hydrothermal synthesis of hybrid inorganic-organic frameworks, iii) Sonochemical stabilization of colloidal particles for edible films.***i) Synthesizing systems with a network of interconnected micro- and mesopores, combining high specific surface area and improved mass transfer is the major challenge in catalysis. The sol-gel technique, whereby a template directs the polymerization of the catalyst precursor in a 3D structure is the main method to synthesize these systems. I anticipate that ULS will improve the intercalation of the structure-directing agent and increase the gelation rate. The interpretation of the results will provide an understanding of the action of ULS on these mechanisms, which misses in the current state of the art.***ii) Periodic mesoporous organosilicas (PMOs) and metal organic frameworks (MOFs) are hybrid inorganic-organic materials with inherent multidisciplinarity bridging fields of application including catalysis, fuel cells, gas storage, absorbents, enzyme immobilization, drug delivery, and imaging. Developing time-efficient syntheses is crucial for their application at the commercial scale (not yet attained). I will adopt ULS to shorten the gelation time to manufacture both PMOs and MOFs, thus replacing slow diffusion syntheses, such as the hydrothermal method, which can take up to several days. ***iii) Combining polysaccharides and proteins with hydrophobic materials or polymers at low concentration produces emulsion-based edible multilayer films with combined O2, CO2, and improved H2O barrier properties. Achieving a stable dispersion is the current challenge to manufacture targeted structures and warrant at the same time the mechanical strength of the film. I anticipate that the ultrasonically generated shock waves will improve the dispersion of the polar and non-polar molecules in water creating a very fine emulsion. We will quantify the effect of ULS on the properties of the emulsions of the hydrophilic polymer with the hydrophobic component and propose successful synthesis strategies.