Robust multifunctional PVA-PAAm hydrogel-based anti-fogging membrane via the construction of active sites

Abstract

In recent years, the demand for transparent substrates (e.g. windows, mirrors and photovoltaic glass) with anti-fogging performances has increased, while conventional anti-fogging coatings, like single-component organic coatings (PVA, PAA, PAAm), show poor stability and cannot maintain their performance stably under harsh environments. In this work, KH570@TiO₂ plays the role of a bottom layer (KT coating) to increase roughness and binding, where the hydrolysis of KH570 anchors the substrate and provides active sites for the binding of the top coating, and the addition of the TiO₂ enhances UV shielding properties. A composite PVA-AAm-POSS-NH₂ gel (PAP coating) served as the top layer, which contains a large number of hydrophilic groups and thus endow the composite coating with satisfactory anti-fogging performance. The strong bonding force provided by the KT coating and the tight physical entanglement of the PAP coating endow the double-layer coating (PAPKT coating) stable anti-fogging performance (60 times of tape peeling test, 100 times of sandpaper friction test, and sand-punching test), and 48 s icing delay performance. The multi-performances make this work great potential in automotive glass as well as building facades to cope with complex situations.