Process chain and characterisation of nanoparticle enhanced composite coatings

Abstract

The structure and the application properties of complex nanoparticulate coatings depend on the entire process chain, i.e. the nanoparticle production, the stabilization, the formulation and the further processing to a coating. Especially the formulation and the dispersing process affect the suspension characteristics and the application properties of the resultant coatings significantly. The aim of this study is to investigate the influence of mean particle size and solids content on the application properties of composite coatings for easy-to-clean surfaces. For this purpose, stable suspensions of hydrophobic alumina nanoparticles of defined particle sizes in styrene are produced. The stable suspensions are then used in a gel coat formulation and coated into sheets using a doctor blade. Finally the coatings are cured and characterised in terms of thickness, contact angle, hardness and abrasion resistance. This example shows how the use of particles with different sizes and mass contents affect the different properties of composite coatings. It is found that all analysed parameters show improved characteristics with decreasing particle size. To confirm the results in more detail and show the obvious influence of the particle distribution on the coating properties, a new AFM method was used to determine interactions on the surfaces in dependency of different formulation parameters.