Research Projects

The project aims to optimize high aspect ratio (HAR) microstructure substrates, also known as micropillar carpets, using three-dimensional meshless simulations. Currently, the design and development of HAR microstructures for hydrophobic substrates are based on heuristics and limited to lithography techniques. The theoretical understanding of dynamic wetting of HAR microstructures is lacking due to limitations in experimental observations in dynamic scenarios. Traditional CFD techniques are challenging due to the fluid-structure interface and high aspect ratio computational domains, making them computationally expensive. The goal is to increase hydrophobicity and reduce hysteresis using parameters such as pillar density, aspect ratio of pillars, and flexural strength of the substrate material. The project will use an in-house meshless multiphysics solver based on Smoothed Particle Hydrodynamics (SPH) to provide quantitative relationships between microstructure mechanical properties and dynamic contact angles. The goal is to propose optimal HAR microstructure designs for different wetting regimes, including the pillars' self-organizing regimes. Some features need development, such as superimposing pairwise inter-particle forces on the continuum domain, developing fluid interaction with 3D filament to represent flexible pillars, and implementing a quasi static evaporation model. The project aims to deliver three groups of deliverables: validations of two and three-dimensional drops on rigid HAR microstructures against theory and experiments, introducing flexural stiffness as a parameter to identify different wetting regimes, and investigating micropillar aggregation during drop motion and drop evaporation.