2.5.2. Emulsion Stability

Stability of the emulsions was determined by following the method reported by Amin et al. [22] with little modifications. Briefly, 6 mL from each coating formulation was taken in a test tube on test tube rack and placed under ambient condition for three days. Stability of the emulsion was measured by the following equation:

$$\text{Emultion stability} = \frac{h\_{\phi} - h\_{\text{f}}}{h\_{\phi}} \tag{1}$$

where *ho* and *ht* is the initial and final height of the emulsion in the test tube after 3 days' time, respectively.

### 2.5.3. Water Vapor Transmission Rate

Water vapor permeability of the coatings was measured according to ASTM method [24] with few modifications. Coating solutions were casted into films and dried at 23 ± 2 ◦C on a smooth horizontal surface until the coating solutions shaped into a thin sheet or films. Glass tubes (5 × 10 cm) were filled with desiccant (silica gel) and dried films were fixed over

the face of the tube (by using gel). Films were placed in the climate chamber (POL-EKO-APARATURA-KK-350, Poland) and maintained at 38 ± 0.6 ◦C and 90 ± 2% R.H. Change in weight of tubes was measured periodically for 7 days to obtain moisture transfer rate. Water vapor permeability (WVP) was calculated by the following equation:

$$\text{WVP} = \frac{\Delta m \times T}{A \times t \times \Delta P} \tag{2}$$

Here, Δ*m* is the change in mass (g) before and after the specific time, *A* is the area (m2), *t* is the time (hours), *T* is the thickness of films and Δ*P* is the difference in pressure at saturated pressure and pressure under the testing conditions.
