“…The volume change can be defined as the volumetric swelling strain, which can be decomposed into the swelling strains in three directions (in-plane, x , and y and through-the-thickness, z ): which can be related to the water uptake as follows (assuming isotropic swelling, the accuracy of which will be discussed below, and constant molar volumes) where L S and L dry are the swollen and dry (initial) dimension length, respectively, and λ ref is the reference water content at which dimensional changes start, usually at λ ref ≥ 2. A simplified expression for the swelling strain, ε swe , can also be written as a linear function of λ, where the calculated swelling-expansion coefficient, β swe = 0.009 ± 0.002, is in good agreement with the experimental data taken from various resources − (Figure ). Similarly, a thermal expansion coefficient, α T , can be defined to relate the thermal strain to temperate change, i.e.…”