Nanophase separation and interfacial entanglements enable tough hybrid polymer networks

Elastomers and hydrogels are essential components in soft robotics and biomedical devices due to their flexible and swollen polymer networks. However, designing soft polymeric materials that reconcile tunable water content and mechanical performance remains a key challenge. Here, we report hybrid polymer networks toughened by nanoscopic arrested phases. The as-prepared, dry elastomeric networks demonstrate a 4- to 25-fold synergistic enhancement in ductility while maintaining high moduli and strength. When fully hydrated, the blend gels display tunable swelling ratio (150-413%), moduli spanning 2 orders of magnitude (6.4-200 MPa), high elongation (230-410%) and toughness (2.5-4.4 kJ m^-2). Such properties are rarely accessible in conventional gels. Morphological investigation reveals distinct reinforcing nanophases of hydrophobic chains, while viscoelastic measurement shows dense entanglements. This platform bypasses traditional solution-based methods, offering a scalable route to tough, functional hydrogels. Our findings establish a blueprint for soft, multiphase materials for soft actuators or biomedical implants.