Titanium oxide layers were deposited onto a BOPP film by atomic layer deposition in order to prevent
UV degradation of the film. The coatings were deposited in a low-temperature process at 80 ◦C by using
tetrakis(dimethylamido)titanium and ozone as titanium and oxygen precursors, respectively. UV block
characteristics of the coatings and their effect on the polymer were measured by using UV–vis and IR
spectrometry, and differential scanning calorimetry. According to the results, the coatings provided a
considerable decrease in the photodegradation of the BOPP film during UV exposure. IR spectra showed
that during a 6-week UV exposure, a 67 nm titanium oxide coating was able to almost completely prevent
the formation of photodegradation products in the film. The mechanical properties of the film were
also protected by the coating, but as opposed to what the IR study suggested they were still somewhat
compromised by the UV light. After a 6-week exposure, the tensile strength and elongation at break of
the 67 nm titanium oxide coated film decreased to half of the values measured before the treatment. This
should be compared to the complete degradation suffered by the uncoated base sheet already after only
4 weeks of treatment. The results show that nanometre scale inorganic films deposited by ALD show a
promising performance as effective UV protection for BOPP substrates.