Ze Wang, Hao Lin, Yuechang Wang, Yuechang Wang, Xiao-Ping Yin, Jinghua Li, Yi Wang, Yi Wang
Enhancing the lubrication and wear resistance of biomedical devices remains challenging. The zwitterionic polymer poly(sulfobetaine methacrylate) (PSBMA) provides superlubricity through hydration but lacks mechanical strength. Poly(ε-caprolactone) (PCL) offers toughness, but its hydrophobicity compromises both lubrication and biocompatibility. The hydrophilic/hydrophobic polarity contrast in solvent-cast PCL/PSBMA composites induces macrophase separation. These microstructures critically govern surface homogeneity, interfacial characteristics, and tribological behavior. Therefore, this study investigates the tribological behavior of solvent-cast zwitterionic PCL/PSBMA composite films exhibiting macrophase separation. Films of varying PCL/PSBMA compositions (30:70, 50:50, and 70:30) were tested against different counterfaces (PTFE, Si 3 N 4, GCr15 balls) under reciprocating and rotational motion modes at loads of 0.5–1.0 N in both air and water environments. Results demonstrate that the P3Z7 film achieved ultralow friction (COF reduction >50%) in water via hydration lubrication, while the P7Z3 films showed superior stability in air.