Abstract
Waterborne colloidal coatings have long been of interest for industrial products because of their low to very low amount of volatile organic compounds (VOCs). However, there is usually a trade-off between achieving coherent and durable coatings. Traditional approaches to overcome this trade-off are to use blends of different colloids or deposit multiple layers. Both have advantages and disadvantages. A new approach is using self stratification. Self-stratification describes the phenomenon in which mixtures of two or more species separate during a film formation process leading to the spontaneous layering such that the composition varies in the direction normal to the surface. This effect happens spontaneously and is not necessarily dependant on the chemical interactions between different species. Harnessing this phenomenon therefore holds the potential to overcome some of the current challenges for performance coatings. Despite intensive research being conducted on the topic of self-stratification of colloidal coating mixtures in recent years, there is still more research needed until self-stratification becomes fully controllable.