Si–O barrier technology for bacterial cellulose nanocomposite flexible displays

Si–O thin film was successfully deposited on bacterial cellulose nanocomposite via plasma enhanced chemical vapor deposition (PECVD) as transparent barrier against water vapor. X-ray photoelectron spectroscopy (XPS) confirmed consistent Si and O atomic concentrations through the entire depth of the Si–O layer. The Si–O layer had uniform and highly smooth surface – more than 80% of the surface features the surface roughness of 15 nm. The water vapor transmission rate (WVTR) of the bacterial cellulose nanocomposite was evaluated as 9 × 10−2 g/m2/day, but after the deposition of the Si–O barrier layer, the WVTR in the range of 10−4 g/m2/day was achieved. The WVTR property of the nanocomposite can be further adjusted through the operating parameters of PECVD. These properties indicated the quality of the Si–O film as an effective water vapor barrier. Bacterial cellulose nanocomposite deposited with Si–O barrier film can be useful as substrate for flexible organic light emitting diode (OLED) displays.