Dr. Patrick Spicer

Associate Professor

School of Chemical Engineering,

UNSW Sydney

 

Host:  Dr. Kelly Schultz

 

Website

 

Dr. Patrick Spicer is an Associate Professor in UNSW’s School of Chemical Engineering where he leads the Complex Fluids Group. His group’s research focus is on design and understanding of natural and synthetic soft materials. He is the Research Director for Chemical Engineering and leads the new Chemical Product Engineering curriculum at UNSW. The new Chemical Product Engineering program teaches development and scale-up of commercial materials that are valuable for their microstructure, flow performance, and composition. Before UNSW, Dr. Spicer ran a central engineering research department for the Procter & Gamble Company in the US for 15 years. His group developed new product and process technology there for all of P&G’s billion-dollar brands.

 

One of the most significant needs in large-scale utilization of colloidal materials is to replace unsustainable or problematic ingredients with renewables. A second key target is to significantly reduce material and water usage, so powders are increasingly attractive as a product matrix. Here we examine the creation of unique hierarchical structures of nanoscale bacterial cellulose fibers by control of fermentation and post-processing conditions. With features varying from tens of nanometers to millimeters, the structures make minimal use of solid mass to form complex, coherent gels. When dried, the materials reduce in volume by orders of magnitude, but the capillary pressures that cause such a drastic change also enable storage of elastic energy in the mesh that can be recovered and applied to speed rehydration. We use light-sheet fluorescence and confocal microscopy imaging to map the full structure of these materials as they are constructed by bacteria. In dynamic flow and hydration experiments we quantify the use of these materials as micron- and millimeter-scale devices and additives for active delivery, product compaction, and biological templates. Building on advances in commercial scale-up of continuous fermentation systems, we are developing new bacterial cellulose production methods to more broadly enable product development.