Comments on fluctuations of cross‐links in gels

Localization of cross-links is an important issue in the theory of rubber elasticity. We consider freely-hinged rigid rod networks and show that in some cases they behave like critical objects: junctions fluctuate on all length scales. Such networks exhibit anomalously low shear modulus and cannot resist shear deformations. These conclusions are very different from the classical picture and might be of some significance for gels near the critical point of volume transition. We comment on the reasons for the different behavior of gels under more usual conditions and raise questions concerning the ability of cross-links to rearrange on scales larger than the mesh size.