*2.11. Water Sorption Measurements*

The rate of the water uptake of the powder samples was measured using a Krüss K100 Force Tensiometer (KRÜSS GmbH, Hamburg, Germany). The powders were loosely packed in capillaries with an inner diameter of 1 mm. As soon as the samples came into contact with water, we recorded the increase in the mass. The Lucas–Washburn equation [51,52] was used to calculate the rate of water sorption:

$$\frac{d^2}{dt} = \frac{(\mathbb{C} \cdot \overline{r})\sigma \cos \theta}{4\eta} \tag{4}$$

where *l* (*m*) is the position of the wetting front, *t* (*s*) is the liquid sorption time, *C* is the quantity describing the orientation of the microcapillaries (*dimensionless*), *r* (*m*) is the average radius of the capillaries (assuming the powder porosity as a bundle of capillaries), σ (*N*/*m*) is the surface tension of the liquid, θ is the wetting angle (*deg*), and η (*Pa* × *s*) is the dynamic viscosity of the liquid [53]. The wetting constant (*C* × *r*) of each formulation was calculated by the LabDesk software (version 3.0, KRÜSS GmbH, Hamburg, Germany).
