(332h) Cracking and Defect Formation in Coatings of Suspensions

Designing and processing complex multiphase materials made of nano- to microscale particles is essential in technologies like batteries, fuel cells, and coatings, where solids, polymers, solvents, and additives are combined into complex fluids and processed into films. Herein, we present a systematic workflow that combines controlled blade coating with image analysis to investigate the evolution of film morphology during drying. As an initial step, we focus on model shear-thinning systems composed of aqueous polyvinyl alcohol (PVA) and silica (Ludox) solution, which exhibit evaporation-induced stress and cracking during drying. We developed and validated a suite of image analysis algorithms—incorporating skeletonization, edge detection, and morphological operation to quantify crack features such as crack width, fragment area. Our results reveal strong correlations between dried film thickness and both crack width and area in the PVA-silica films. These findings establish a foundation for linking rheological properties to drying-induced mechanical failures. Once this image-based workflow was validated with well-controlled model systems, we extended our approach to more complex suspensions—those exhibiting shear-thickening behaviors (Silica-Polyethylene oxide aqueous solution), composed of non-spherical or polydisperse particles. This presentation will summarize recent results from these ongoing experiments, highlighting how changes in formulation complexity impact film formation and final film integrity.