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Titanium dioxide’s self-cleaning effect has been broadly used in textiles, paints, windows, residual water treatment, amongst various other photocatalytic applications. Polymer substrates have found their way in the semiconductor industry as a base layer for flexible electronics, as well as in sensor and actuator applications. The optimum performance of these systems may be affected by dirt adsorbed on its surface, which can also originate mechanisms for the degradation of the polymer. The authors have endured an extensive research in order to enhance the photocatalytic efficiency and the mechanical properties of titanium dioxide thin films on glass and polymer substrates. These thin films have been deposited by unbalanced reactive magnetron sputtering from a high purity Ti target in an Ar/O2 atmosphere, at room temperature on polymer sheets, such as á- and â-PVDF, the copolymer PVDF-TrFE and Polycarbonate. Rutherford Backscattering experiments evidenced that these coatings have a TiO2 stoichiometry, which remains stable after thermal annealing in vacuum at 500 °C. X-ray diffraction revealed that the as-deposited coatings are mostly amorphous, however some evidence of anatase crystalline phases are apparent from Raman spectroscopy experiments. The photocatalytic behaviour of the titanium dioxide coatings was determined by combined ultra-violet irradiation and absorption measurements. In order to assess the mechanical behaviour of the as-sputtered films, the film/substrate composite system was loaded unidirectionally using a tensile testing machine. The stress-strain curves were analysed and correlated with photocatalytic efficiency and structural data. For a 5% deformation of the composite system with electroactive â-PVDF yielded better photocatalytic behaviour, while the porous polymers manifested severe adhesion problems that hinders application of the self-cleaning coatings. |