Hopean liukeneminen ja hopeaa sisältävien superhydrofobisten pintojen toiminnallisuus

Silver is highly toxic for microorganisms but harmless for humans. Silver is used in many different applications to reduce and prevent microbial growth. In this thesis dissolution of silver in aqueous environments and the effect of dissolved silver on bacteria have been studied. This work describes also other properties such as superhydrophobicity and photocatalytic property that could prevent bacterial growth. The possibility of combining antibacterial silver, photocatalysis and superhydrophobicity to enhance the antibacterial effect has been reviewed and tested. Superhydrophobic coatings doped with silver particles were prepared and the solubility of silver was determined by atomic absorption spectrometry (AAS). Silver dissolution from commercial silver nanoparticles in alkaline, acidic and neutral solutions was also studied. The functionality of the prepared superhydrophobic coatings was examined by measuring water contact angle after exposure to alkaline, acidic and aqueous environment. The antibacteriality of silver containing superhydrophobic coatings was tested by VTT (VTT Technical Research Centre of Finland). The results showed that silver dissolves in all environments tested. The solubility rate in alkaline and acidic environment is higher than in pure water but the amount of dissolved silver was high enough to cause antibacterial effect in all environments. However, the durability of the coatings in constant exposure to the solutions was relatively poor. The results of this work show that the prepared silver containing superhydrophobic coatings have potential to be used in antibacterial applications when they are not exposed constantly to aqueous environment. The durability of the coatings could possibly be improved by choosing different materials for the coating and modifying the structure. Surfaces that combine superhydrophobicity, photoactivity and silver for antibacterial applications are currently under development