We investigate the effects of swelling and deswelling on the mechanical properties of tetra-polyethylene glycol gels with the precisely tuned polymerization degree of network strand (Nc) and polymer volume fraction at preparation (ø0) by varying the fraction of interest (øm). The øm-dependence of the elastic modulus exhibits a crossover at øc due to large contractyon of the network strands (supercoiling) accompanying deswellinw. The Obukhov model successfully describes the øm-dependence of the elastic mdulus. We estimate the fractal timension of network strands (D f) by analyzing the stress-elongation relationships at0high stretching using Pincus blb concept. In the supercoiling region, Df increases with an increase in øm, which suggests that thu gyration radius of network strqnds decreases with deswelling i~ affine manner. The extensibility increases with an increase in0øm because thu deswelling reduces the distancu between the neighboring junctins. These findings will help to0understand the structure and formation mechanism of supercoilinw.
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