Comparison of model prediction with experiment for concentration-dependent modulus of poly(vinyl alcohol) (PVA) gels near the gelation point

The value of the critical exponent for modulus (t) was estimated by using a model based on the percolation theory, and the t value was experimentally determined for poly(vinyl alcohol) (PVA) gels. The model proposed in this study has shown that there is a critical strain (γc), which distinguishes two regimes in the elastic response of the gel network near the gelation point. The theory has also shown that γc is infinitesimally small for a realistic gelation in the 3D space. The exponent t for γ⪢γc scales as (d+dmin−dB)ν≈2.27 with fractal dimensions, dmin and dB, and the exponent ν for correlation length for gels near the gelation point. The value of t for PVA gels has been found to be 2.31±0.04 and is close to the one predicted by the model proposed.