Method for preparing a barrier film

A method for preparing a water vapor transmission barrier film, the method comprising:

• coating a composition comprising an amine catalyst and a polysilazane on a base layer via a wet coating process to form a barrier layer, wherein:
• the amine catalyst is ammonia, ammonium hydroxide, ammonium chloride, trialkylamine, dialkylamine, monoalkyl amine, dialkanolamine, dialkylalkanolamine, trialkanolamine or dialkylaminoalkyl trialkoxysilane;
• and
• the amine catalyst is present in an amount within a range of 0.1 to 10 parts by weight relative to 100 parts by weight of the polysilazane;
• and
• subjecting the barrier layer to a curing process that includes performing a plasma hardening treatment comprising plasma-treating a surface of the barrier layer containing the polysilazane and the amine catalyst in a processing space in which water vapor, a discharge gas, and oxygen as a reaction gas are injected resulting in maintaining a vapor pressure of water vapor in the processing space at about 5% or more to cause oxidation of the polysilazane whereby SiN units of the polysilazane are converted into Si—O units in a thickness direction to layer satisfy Equation 2 below thereby yielding the water vapor transmission barrier film:
• 0.75≤d/(c+d)≤0.97 [Equation 2]
• wherein:
• c is the number of Si—N units present in the barrier layer after the plasma hardening treatment, and
• d is the number of Si—O units present in the barrier layer after the plasma hardening treatment.