Assessing the Validity of Jacobs’ Model Through Conversion Measurements in Photopolymerized Resins

Abstract This study examines the applicability and limitations of Jacobs’ model in vat photopolymerization. Working curves generated for four resins cured at two irradiances showed a good agreement with Jacobs’ law. The calculated energy exposures received at the top of the printed pillars are consistent across curing conditions and match the critical exposure energy, validating the working curve methodology. Furthermore, ATR-FTIR spectroscopy revealed a similar monomer conversion (20–25%) at the top of the pillars for all formulations, supporting the hypothesis that this region corresponds to the gelation threshold. These results quantitatively connect Jacobs’ parameters to the degree of polymerization, providing deeper insight into the curing process and enabling more precise control over vat photopolymerization conditions.