The membrane was oxidized through a photochemical treatment
under oxygen in order to confer to thematerial as a hydrophilic character.
During this process, low pressure oxygen (400 mbar) is exposed to
UV light using a xenon excimer lamp (172 nm). This step involves oxygen
radicals and ozone active species that react with the diamond surface.
It has been shown that this surface treatment leads to hydroxyls
and ethers' surface moieties [24]. Before oxidation, the hydrophobic
character of the hydrogenated diamond membrane is illustrated
through the water droplet angle depicted in the Supporting information.
After oxidation, the high hydrophilic character of the membrane
does not allow water droplet formation anymore.