Photo-controlled living polymerization has received great attention in recent years. However, despite the great success therein, the report on photo-controlled living cationic polymerization has been greatly limited. We demonstrate here a novel decolorable, metal-free and visible light-controlled living cationic polymerization system by using tris(2,4-dimethoxyphenyl)methylium tetrafluoroborate as the photocatalyst and phosphate as the chain transfer agent (CTA) for polymerization of 4-methoxystyrene. This polymerization reaction under green LED light irradiation shows clear living characteristics including predictable molar mass, low molar-mass dispersity (Đ = 1.25), and sequential polymerization capability. In addition, the photocatalytic system exits excellent “on-off” photo switchability and shows the longest “off period” of 36 h up to now for photo-controlled cationic polymerization. Furthermore, the residual photo-catalyst is easily deactivated and decolored with addition of a base after the polymerization. The present study has extended the photo-controlled living cationic polymerization systems with new organic photocatalysts, phosphate CTA and polymerizable monomer as well as the new properties of excellent photostability and in-situ decolored capacity.

光控活性聚合近年来受到了极大的关注。然而，尽管在这方面取得了巨大成功，但关于光控活性阳离子聚合的报道却非常有限。我们在这里展示了一种新型的可脱色、无金属和可见光控制的活性阳离子聚合体系，使用三（2,4-二甲氧基苯基）四氟硼酸甲酯作为光催化剂，磷酸盐作为链转移剂 (CTA) 聚合 4-甲氧基苯乙烯. 这种在绿色 LED 光照射下的聚合反应显示出明显的活性特征，包括可预测的摩尔质量、低摩尔质量分散性 ( Đ = 1.25), 和顺序聚合能力。此外，该光催化体系具有出色的“开-关”光切换能力，并显示出迄今为止最长的光控阳离子聚合“关断期”36 h。此外，聚合后残留的光催化剂很容易通过添加碱而失活和脱色。本研究通过新型有机光催化剂、磷酸盐 CTA 和可聚合单体扩展了光控活性阳离子聚合体系，并具有优异的光稳定性和原位脱色能力等新特性。