Highly Elastic and Deformable Hydrogel Formed from Tetra-arm Polymers

After decades of efforts by many researchers, we have succeeded in realizing a near‐ideal polymer network. This network, the Tetra network, is made by cross‐end‐coupling of tetra‐arm polymer modules. The mechanical energy dissipation was extremely low (tan δ ≈ 10−4). The macroscopic stress–strain relationship of the Tetra network was in good agreement with that of microscopic elastic blobs. The maximum breaking strength was extremely high (≥27 MPa). These results indicate that the Tetra network is closer to an ideal polymer network than any other conventional model networks. Because the Tetra network can be treated as uniformly packed elastic blobs, it should help apply the knowledge of single polymer chains seamlessly to the design of polymer materials and help further develop the theory of rubber elasticity. An “ideal” network is a polymer network consisting of an infinite series of uniform meshes connected by cross‐links without any inhomogeneities. Here, we show a near‐ideal polymer network, the Tetra network, made by cross‐end‐coupling of tetra‐arm polymer modules. The homogeneity of the Tetra network should help apply the knowledge of single polymer chains seamlessly to the design of polymer materials and help further develop the theory of rubber elasticity.