Measurements of the Swelling Ratio

The swelling ratio experiments were conducted weighting the dried and the humid hydrogel. To that, a dried hydrogel sample cut into sheets with thickness of 2 mm and diameter of 6.3 mm, and then 10 sheets were weighed. Then, the samples sheets were immersed in deionized water at room temperature and after that the hydrogel samples sheets were removed from the water and weighted. Swelling measurements were conducted in triplicate for each sample. The swelling ratio (SR) was calculated using the equation:

Where Ws is the weight of the swollen sample sheets, Wi is the initial (dried) weight of the hydrogel sample sheets. The swelling ratio is expressed as percent weight ratio.