Engineering nanoscale roughness on hydrophobic surface : preliminary assessment of fouling behaviour

A preliminary investigation of the fouling behaviour of smooth and roughened superhydrophobic coatings is reported. The effect of nanoscale interfacial roughness on the adhesion of single (SW8) and mixed cultures of micro-foulant for periods of up to 6 months was assessed using visual and wettability measurements. Detailed analysis indicated virtually no micro-organism attached to the superhydrophobic surfaces in the first weeks of immersion. As a result by comparison with smooth substrates, which exhibited fouling within a day, very rough (roughness ratio >2.7) surfaces exhibited high resistance to fouling over a 6-month period. However, after periods exceeding 2 months under ocean conditions, both films showed limited anti-fouling properties. There appears to be a correlation between the nature of the nanoscale roughness in the creation of superhydrophobic coatings and their potential anti-fouling properties. The future architecture of such a correlation is investigated.