Type II Photoinitiation Mediated by ZnTPP and ZnPC : Electron‐Transfer Mechanisms With TEOA / DPI Co‐Initiators

During photopolymerization, the large molecular size and complex entanglement of the products may result in the physical encapsulation of the photosensitizers within the polymer matrix, potentially influencing material properties and introducing additional optical activity, which can alter the material properties in product performance and even introduce unwanted additional optical activity. In contrast, in fields such as photodynamic therapy, organic synthesis, and wastewater treatment, the retention of photosensitizers within the products can provide sustained reactive functionality. ZnPC and ZnTTP exhibit excellent photochemical activity due to their unique rigid structures and closed‐shell configurations. In this work, these two zinc‐coordinated photosensitizers were employed in TEOA/DPI‐assisted systems for photopolymerization. The photopolymerization mechanisms of ZnPC‐ and ZnTTP‐based initiating systems were elucidated through double bond conversion, cyclic voltammetry, and electron paramagnetic resonance analyses. Furthermore, the singlet oxygen production efficiencies of the two compounds were measured, which confirmed the hypothesis that ZnPC and ZnTTP were retained within the products, and provided two possible products with potential as photosensitizers.