The use of contact angle measurements to estimate the adhesion propensity of calcium carbonate to solid substrates in water

We have studied a series of solids using contact angle measurements; stainless steel, gold, aluminium, titanium nitride and PTFE that are frequently used in domestic water environments. It was found the influence of electron-donor (γ−) and electron-acceptor (γ+) free energies on material scaling rate was dominated by water wetting angles, providing materials exhibit an average roughness below 100 nm. The γ− component had the greatest influence on theoretical adhesion, while γLW, (Lifshitz-van der Waals) γ+ and γAB (acid-base) had little effect. From the materials analysed, amorphous carbon coatings were least adhesive, while ‘kettle coating’ and highly roughened steel the most adhesive. The size and distribution of asperities also influenced the polar free energies and subsequent adhesion due to fluctuations in the wetting angle. The results obtained indicate works of adhesion can be used as a complementary technique with Lewis acid–base theory to deliver useful information about the propensity of scale to deposit on solids.