Contact Angle and AFM Analysis of Glassy Carbon Coatings after an Extended Stay on the International Space Station (ISS)

The proposed work presents the results for contact angle and atomic force microscopy (AFM), which are applied to characterize the surface of two types of samples, “reference” sample and “space” sample, both made of the same material – graphite covered with glassy carbon coating, but stored for 28 months in different environments (conditions). One “space” sample was mounted outside the International Space Station, and the other “reference” sample was stored on Earth. The technique applied to measure the contact angle of wetting of the surface of the samples (hydrophilicity-hydrophobicity) is using water droplets. Values of the energy surface area of the sample surfaces were determined by measuring the contact angle with the substances formamide and diiodomethane. Atomic force microscopy (AFM) was applied to characterize the glass surface morphology of carbon coatings.