This invention provides water-swellable articles and hydrogels that contain a hydrophilic polymer and perfluorocyclobutane crosslinking segments. The perfluorocyclobutane crosslinking segments are covalently attached to the polymeric chains of the hydrophilic polymer so that the crosslinking segments chemically link the polymeric chains to each other. The present invention also provides a method of making a crosslinked hydrogel by first attaching one or more substituted aromatic trifluorovinyl or aromatic trifluorovinyl ether moieties to a hydrophilic polymer to form a modified polymer and then heating the modified polymer at an elevated temperature to form perfluorocyclobutane segments from the trifluorovinyl or trifluorovinyl ether moieties. These water-swellable articles and hydrogels may be used in biomedical and pharmaceutical applications and may be suitable for implanted joint repair materials such as an articulating or bearing surface in a hip, knee, spine, finger, ankle, elbow, wrist, or shoulder joint.