Titanium dioxide deposition on consumer technical products

With the PLASMONWIRE project "Atmospheric pressure PLASMA deposition of PLASMONIC coatings ON a WIRE substrate", funded by the Luxembourg National Research Fund, researchers at the Luxembourg Institute of Science and Technology (LIST) have been working for three years on the synthesis at atmospheric pressure of functional titanium dioxide (TiO2) deposits. This chemical compound, which is widely used in powder form in the cosmetics, food and even chemistry sectors, can be used for other applications if it is synthesised in the form of a deposit on a functional part. Some techniques are already in use, but they require the part to be coated to be heated above 150°C and nanoparticles to be handled in order to achieve spiking. Moreover, they cannot always be industrialised because they are not productive enough given their low rates of deposition.

Deposition of TiO2 in one single stage

With PLASMONWIRE, which has now come to an end, specialist process engineering and prototyping researchers were able to develop a chemical synthesis method that is capable of producing deposits of TiO2 in one single step, which in turn could be spiked by various other chemical elements. This method, which is carried out using plasma under atmospheric pressure, can produce layers about 100 nanometres thick with nanometric grain sizes and anatase-like crystallographic structures. These functional deposits can be carried out on heat-sensitive substrates such as polymers, with very fast rates of deposition.

A demonstrator has been developed to continuously coat optical fibres with a photocatalytic film that is active in a wide wavelength range as a result of the spiking. It is therefore now possible to consider treating liquid or gaseous media  in environments that are not open to external lighting.

A possible application for water decontamination

During the project, a possible application of the coated material for use in water decontamination was carried out in partnership with LIST researchers specialising in environmental innovation. Together, they were able to establish degradation kinetics for water polluted by an antibiotic (sulfamethoxazole) as a function of the active surface of various spiked nanocomposite TiO2 deposits.

Finally, this project enabled the team to produce 7 scientific publications, 2 registered patents, and a thesis conducted in partnership with University College London (UCL).