Sponge porosity measurement

The sponge porosity was measured by the immersion medium method. First measure and record the size and weight of the initial sponge. Then the sponge was soaked in absolute ethanol for 10 min at room temperature. Finally, the sample was taken out gently and the weight of the soaked sponge was measured. The result of porosity is the average value for 3 times of testing. The porosity is calculated by the following equation (Singh and Jelinek, 2020).

Where m and m_a correspond to the weight of the sponge before and after adsorption of ethanol. ρ is the density of absolute ethanol. l, w, h correspond to the length, width and height of the sponge respectively.