A Hybrid Experimental and Model-Based Methodology for the Formulation of Self-Stratifying Coatings

A systematic procedure to formulate self-stratifying coatings using a hybrid experimental and model-based methodology has been developed. Herein, first different combination pairs of polymeric resins are screened through computer-based algorithms. These make use of models to predict the physicochemical properties which are responsible for the different factors that affect self-stratification. A few promising candidates for preparing the formulations are selected. First, only the polymeric resins are studied for phase separation. The resins showing phase separation are combined in optimum quantities to produce 500 μm films (wet film thickness) on plastic substrates, which are then evaluated for the degree of stratification using FTIR-ATR and SEM-EDS analysis techniques. The difference in the absorption spectra of the top and bottom surfaces of these films as well as a significant difference in topography of the microscopic images across the cross-section confirmed the occurrence of stratification. Following this evaluation, the effect of solvents and pigments on the extent of stratification will also be considered.