Turing Newcastle AkzoNobel DSG Report 2023

AkzoNobel is a global leading paints and coatings company, providing solutions to customers across a wide range of business segments from consumer goods to heavy industry (e.g. Oil and Gas and Marine industry). International Paint is a brand of AkzoNobel delivering paints/coatings solutions to the Marine, Yacht and Protective industry.

A major challenge for the marine industry is biofouling, the unwanted colonisation of marine/aquatic organisms on immersed substrates, which includes ship hulls. Biofouling on ships’ hulls increases hull surface roughness, which in turn increases frictional resistance and ultimately increases fuel consumption and total emissions of a ship. A biofilm is a type of biofouling and is a slimy layer made of living microoraganisms embedded in an extracellular polymeric matrix.

Biofilms on ships are known to increase the drag penalty by up to 40%. The degree to which a biofilm affects drag can be practically measured in hydrodynamic experiments - but such approaches require metre-scale sections of hull material (and biofilm) for testing purposes. As it is not practical to source large volumes of testing material directly, modern 3D printing technologies may offer an alternate solution, if these can accurately replicate sample materials and their surface properties.

Surveys of ships around the world show that, even visually, not all marine biofilms are the same. Variance in biofilms, attributed to differences in both the composition and community, results in differences to the frictional drag. Historically it was a real challenge to measure the surfaces of biofilms but more recently, biofilm imaging has opened up with the adoption of a technology called optical coherence tomography (OCT). OCT lets us image down through living biofilms over a surface area approximately the size of a penny.

Therefore, if practical drag measurements need metre-scale material samples, but OCT imagery can only provide centimetre-scale images, the open question for this project was to find a suitable methodology to replicate OCT textures at the metre-scale, potentially providing templates

3 for 3D printed hull sections suitable for hydrodynamic experiments.

The data available for the project was 36 sample OCT scans in the format of plain text files. Each file has the dimension 500x500 and depth values between 0 and 900, representing an elevation map covering 9mm x 9mm x 2.5mm biofilm.