Acquisition of a Scanning Ultrasound Analyzer for Gelation and Drying Studies inSol-Gel Ceramic Coatings and Monoliths

摘要

The overall goal of this research project was to develop a fundamentalunderstanding of how colloid chemistry influences structure and properties of ceramic monoliths fabricated by sol-gel synthesis from colloid suspensions. The specific objective in the first part of the project was to determine how the interaction potential between colloidal particles influenced gel structure and strength. We proposed to do this using Stokesian Dynamics computer simulations and time-dependent ultrasonic measurements of elastic modulus for gels synthesized using various colloidal silica sol concentrations and electrolyte strengths. Detailed negotiations about equipment pricing and capabilities revealed that a simpler experimental method (mechanical rheometry) could be more effective than the proposed ultrasonic technique for elucidating time-dependent gel structure evolution and yielding. With the written permission of Dr. Pechenik, the Program Director, funding allocated for purchasing the ultrasonic device and designated matching funds from Texas AM University were used to purchase a Paar Physica Universal Dynamic Spectrometer (UDS). During the last year this instrument was successfully purchased installed at Texas AM University and is already shedding needed light on the gelation kinetics of concentrated colloid suspensions. The following report summarizes our reasons for choosing the UDS and provides an overview of our research findings using the instrument.