The ability of ALD deposited TiO2 surface coatings to protect
BOPP film against UV induced photodegradation was investigated.
The coatings were produced from TDMAT and ozone precursors
in a low-temperature ALD process having the process temperature
(80 ◦C) clearly below the substrate’s melting point. The results
showed that the 36 nm TiO2 layer as measured on silicon samples
provided a moderate and the 67 nm layer significant UV protection
for BOPP. It is also demonstrated that there is a significant difference
in the thickness of films on BOPP compared to silicon because of an
extended nucleation period which needs to be taken into account
when estimating the thickness. According to IR analysis, the 67 nm
coating was able to largely prevent the formation of the main photodegradation
products in BOPP after a 6-week UV exposure. DSC
analysis showed that neither the UV treatment nor the TiO2 coating
process affected the degree of crystallinity in BOPP. However,
the melting behaviour of samples indicated that the TiO2 coating
protected the BOPP film from UV degradation.