2.6. Water vapor permeability (WVP) and water contact angle (CA)
Water vapor transmission rate (WVTR) of the film sample was
determined gravimetrically at 25 °C under 50% RH conditions using
water vapor transmission measuring cups in accordance with the
ASTM E96-95 standard method. Then the WVP (g·m/m2·s·Pa) of the
film was calculated using the following equation: