Lead University: Carnegie Mellon University
PI: James Schneider, Chemical Engineering
Co-PIs: Aditya Khair, Chemical Engineering

This proposal aims to develop a means to measure the surface charge of polymer-titania composite particles used in architectural paint formulations. The project is a collaboration with Dow Chemical Company (Collegeville PA), one of the largest producers of paint compounds in the world. These composite particles greatly reduce the amount of titania required in architectural paints, leading to substantial decrease in the energy required for the synthesis of titania and energy required for transportation of the resulting paint products. Due to the nature of the polymer-titania interactions, these composite particles have a diverse surface chemistry, and as such, it is expected that measurement of averaged properties will not adequately predict the stability of these composite particles in paint. To address this, we will develop a microfluidic electrophoresis system to measure the surface charge on individual particles, one at a time. This "digital" approach will capture rare chemistries that may play an outsized role in dictating stability. Simulations of particle aggregation will also be performed using the data collected and compared with stability measurements to validate the digital characterization approach. First, a simpler latex model system will be used, with a series of buffers that will allow control of the stability with precision. Later, the method will be applied to the composite particles. All materials for characterization will be supplied by Dow Chemical using a high-resolution sizing technique called asymmetric flow field flow fractionation.