The influence of nanobubbles on the interaction forces between alumina particles and ceramic foam filters

With decreasing wettability and rough surfaces the adhesion forces between the interacting surfaces shift to higher values. This is due to capillary bridging by nanobubbles which are sitting on one or both rough surfaces and cause capillary interactions. For particles, the coverage with such bubbles for different wettability and gas oversaturation is shown. Also, it is possible to identify three general types of force distance curves: curves with no capillary interactions, curves with capillary interactions but no repulsion during approach and curves with capillary interactions and a small repulsion just before snap-in. Possible reasons for repulsion are analysed and a calculation of Hamaker constants is presented. Furthermore, well-known models for adhesion on rough surfaces are compared with the experimental data. (C) 2019 Published by Elsevier B.V.