Block copolymer synthesis and photoinitiated grafting via a dual-wavelength photoinitiating system based on Iragcure 2959 derivative/camphorquinone

Abstract

Although photopolymerization offers notable environmental advantages and rapid curing properties, its application in the synthesis of structurally complex polymers remains limited due to inadequate control over polymer chain initiation and propagation by conventional photoinitiators. To overcome this limitation, a novel dual-wavelength photo-initiating system (2959-EDB/CQ) was developed in this study. 2959-EDB initiator incorporates an α-hydroxy ketone moiety at one end and a tertiary amine group at the other, enabling sequential activation under 465 nm (via camphor quinone-mediated hydrogen abstraction) and 275 nm (C–C α-bond cleavage) irradiation to produce distinct radical species for the controlled polymerization of different monomers. In contrast to conventional bisacylphosphane oxide (BAPO)-based systems, which are prone to photolytic interference, the proposed system allows for the efficient synthesis of well-defined diblock copolymers. Notably, the residual α-hydroxy ketone groups on the initially polymerized surface can be reactivated to initiate UV-induced graft polymerization, as demonstrated by attenuated total reflection infrared spectroscopy, morphological analysis, and contact angle measurements. 2959-EDB/CQ system combines high radical reactivity with procedural simplicity, overcoming the cost-related drawbacks of RAFT-based strategies for diblock copolymers synthesis while retaining the industrial practicality of conventional photopolymerization. This study presents a versatile platform for the synthesis of block copolymers and the functionalization of polymer surfaces.