Transparent and flexible vesicles/lamellae mixed matrix organic-bridged polysilsesquioxane coatings as water vapor barrier

Siloxane-based hybrid materials with lamellar nanostructure have great potential to be water vapor barrier layer for electronic devices and photovoltaic cells encapsulation. Improving water vapor barrier ability was still a big challenge. This research article proposed a facile one-pot methodology to prepare vesicles/lamellae mixed matrix organic-bridged polysilsesquioxane (BPSQ) composite coatings with excellent water vapor barrier performance. The composite coatings were fabricated from three thioether-ester-briged silsesquioxane by sol-gel method in the presence of phytic acid. Phytic acid not only acted as catalyst to catalyze the hydrolysis and condensation reactions of silsesquioxane precursors, but also formed vesicles in ethanol solution. Experimental evidence demonstrated that vesicles size mainly influenced the barrier property of composite coatings, and with bigger vesicles, the composite coating showed 10-fold enhancement in water vapor barrier ability compared to the corresponding BPSQ coating with only lamellar nanostructure. Moreover, the vesicles/lamellae composite coatings displayed outstanding transparency and flexibility which would meet the requirements of optical related moisture resistant application fields.