Immersion precipitation 3D printing (IP-3DP) holds significant potential for biomedical applications due to its ability to create complex porous microstructures. This study systematically examines how printing parameters affect the structural characteristics and functional performance of polycaprolactone (PCL) scaffolds fabricated via IP-3DP. To clarify micrometer-scale porous structure formation, we established a ternary phase diagram for the polycaprolactone (PCL)/dimethyl sulfoxide (DMSO)/water (H2O) system. Key printing parameters, including needle moving speed, extrusion pressure, PCL concentration in the ink, and DMSO concentration in the coagulation bath, were varied systematically. This approach quantified their impact on print fidelity, filament morphology, porosity, and mechanical properties. We further explored the relationship between surface pores and biomedical performance. Thermodynamic analysis based on the ternary phase diagram revealed the dynamics of phase separation during the formation and evolution of porous structures during printing deposition and solidification. We observed that increasing the PCL concentration in the ink reduced filament cross-sectional porosity while enhancing mechanical strength. A higher DMSO content in the coagulation bath decreased internal porosity while improving surface porosity and interlayer bonding. The optimized parameters enabled precise fabrication of scaffolds with controlled macro-geometry and micron-scale pores, where surface pores were found to significantly enhance cell adhesion. These findings provide fundamental guidelines for microstructure control in IP-3DP applications.
Gao et al. (2026) studied this question.