Film Formation in Complex Colloidal Coatings

In this project we aim to establish a new understanding of film formation in latex coatings, composed of polymeric binder particles and optionally pigment particles dispersed in water. These coatings serve as a model for e.g. waterborne paints.

Coatings are an essential part of everyday life. Their applications range from low-tech surfaces such as walls, furniture, and consumer appliances, to high-performance technologies such as cars, airplanes, and military equipment. Over the past 30 years, the market share of waterborne coatings has been increasing at the expense of solvent-borne formulations. These water-based systems are more environmentally friendly and healthier for consumers. However, waterborne coatings cannot yet compete with solvent-based coatings in terms of durability and performance.

The formation of a continuous film from a water-based colloidal dispersion is a complex process. In this project we aim to shed new light on the mechanisms behind the different stages of film formation, with particular focus on the last stage of coalescence.  Proper coalescence of the binder particles has proven to be crucial in producing a mechanically and aesthetically appealing film.

We will investigate a variety of key parameters governing the film formation and coalescence mechanisms, such as the particle viscosity, size and surface chemistry, and the presence of different types and concentrations of surfactants and pigments. To obtain a comprehensive picture of the film formation process, we will complement optical measurements (light and confocal microscopy) with structural measurements (scanning electron microscopy and atomic force microscopy) and dynamical measurements; for the latter an advanced light-scattering set-up is being designed and built. These techniques allow us to resolve the film formation process both temporally and spatially.