Adhesion and repulsion between calcite surfaces
Joanna Dziadkowiec, Physics
Calcite is a common mineral resource and its consumption reaches over 4 billion tonnes each year. Most of is burned as a source of calcium oxide for cement production and less than 30% of mined carbonates are used as fillers and pigments in paper, plastics and paints. Calcite is thus usually an inert filling material with no specific function. On the contrary, calcite in biominerals has a very specific and advanced function such as in lenses, gravity sensing systems or crack-resistant shields. This offers remarkable potentials to engineer calcite in man-made materials.
Our approach is to investigate and modify surface properties of calcite by experimental measurements of forces between calcite surfaces. We seek at which conditions calcite surfaces repel each other and when they attract each other. We use water, electrolytes and organic additives. We observe repulsive interactions in water and low-concentration electrolytes and adhesive interactions in concentrated electrolytes and solutions of long-chained dicarboxylic acids. We follow the notion that in order to improve the properties of calcite-based materials, strong attractive links between calcite surfaces are needed and we explore these forces in our experiments.