Symbol Definition Value Remark
vw Volume of a lattice (= volume of a H2O molecule in liquid phase) 3.0 × 10-29 m3 Constant
Vi Initial volume of a gel in a fully swollen state 1.0 × 10-16 m3 [19] Constant
φNIPA Volume fraction of pNIPAM (=VNIPA/Vi) 1/20 Constant
A Elasticity-associated coefficient (dimensionless) -6.4 [13] Constant
Θ Flory’s Θ temperature of pNIPAM 315 K [13] Constant
χbio
Flory-Huggins interaction parameter between tissue-derived biopolymer and water (dimensionless)
0.161 for intact (composite) collagen type I [15] 0.107 for pronase-digested collagen type I [15] 0.48 for a gelatin coil [17] 0.49 for gelatin in coil + helical states [17,18]
Semi-fixed (4 different values)