Hydrophilic polyurethane foam has a high moisture absorption amount which is prone to swelling, aging, and deformation. Moisture barrier strategy for this kind of material faces great challenges due to the abundant polar groups, porous structure, rough surface, and poor thermal stability. Here, multilayer organic inorganic composite reactive coating is developed to construct a high moisture barrier interface for polyurethane foam.
The inner layer is active reactivity barrier coating which remedies the defects on the foam surface and GO/MgO as active filler to both reaction with H₂O molecules and barrier water permeation. An intermediate layer is dense Si-doped DLC films obtained by HPCIII method to provide a strong barrier for water permeation. The outer layer is the slippery liquid-like brush to weaken interaction with H₂O and decrease the adsorption amount of H₂O.
The multilayer coating exhibits excellent moisture barrier by combining physical barrier and chemical reaction, interface adhesion with PUF foam and corrosion resistance, and self-cleaning performance. This work provides a novel and feasible method for the moisture barrier of hydrophilic foam. 
 

Moisture Barrier, Active components, Polyurethane foam, Si-doped DLC film, Liquid-like brush