Evaluation of Topological Defects in Tetra-PEG Gels

We have investigated the topological defects in the Tetra-PEG gel formed from two symmetrical tetra-arm polymers. The concentration of the elastically effective chains (EEC) was estimated from the elastic moduli and the reaction efficiency using the tree-like Miller-Macosko model. The concentration of EEC was in the range between the estimations of the affine and phantom theory. Furthermore, the formation of topological defects, especially entanglements and loops, was found to be negligible in the Tetra-PEG gel, which differs from other conventional model networks. This extremely homogeneous structure was formed due to the unique impenetrable sphere-like behavior of the tetra-arm star polymer in the semidilute solution and the unique symmetrical A−B type cross-end-coupling.