Makromol. Chem., Rapid Commun. 12,347-351 (1991) 341 Photoinduced charge-transfer copolymerization of N-vinylcarbazole with 2-(dimethylamino)ethyl methacrylate Irini Sideridou-Karayannidou George Karayannidis, Georgia Seretoudi George Stalidis Department of Chemistry, Aristotle University of Thessaloniki, GR-54006, Thessaloniki, Greece (Date of receipt: January 28, 1991) Introduction It is well known that the photosensitized reaction of N-vinylcarbazole (VCZ) in the presence of various electron acceptors involves its cationic polymerization, cyclodi- merization or radical polymerization In certain cases, when the electron acceptor is at the same time a monomer capable of undergoing radical polymerization, radical copolymerization between VCZ and the monomer can also take place. This multireaction course was attributed to the dual cationic and radical reactivity of the intermediate VCZ cation radical formed by the electron transfer from VCZ to the electron acceptor in the excited state. In polar basic solvents, such as acetone or acetonitrile, cyclodimerization of VCZ takes place exclusively. By contrast, in less basic solvents, e. g. dichloromethane, benzene, etc., cationic polymerization proceeds, whereas in strongly basic solvents like DMF or DMSO radical polymerization and cyclodimerization of VCZ occurs4). The photochemical reactions of VCZ are also influenced by the atmosphere '1. When oxygen is present, the yield of polymerization and cyclodimerization is increased because oxygen acts also as an electron acceptor. The cyclodimer of VCZ is most probably formed by a radical reaction of VCZ cation radical with the VCZ monomer to give VCZ dimer cation radical, followed by an elec- tron back-transfer to it and cyclization '). However, when in the VCZ-oxygen-acetone system, which upon irradiation affords exclusively cyclodimer 3), triethylamine (TEA) was added, the cyclodimerization of VCZ was completely quenched and only radical polymerization of VCZ was confirmed4). This effect was attributed to hydrogen atom transfer between the excited VCZ and the ground-state amine, leading to free-radical species which initiate radical polymerization, and, most importantly, to the electron transfer from TEA to the VCZ cation radical (VCZt) with concurrent formation of neutral VCZ and cation radical TEAt '). The quenching of VCZt by TEA may be responsible for the complete quenching of cyclodimerization of VCZ in the above system. 2-@imethylamino)ethyl methacrylate (DMAEM) is an electron acceptor monomer which can undergo radical and anionic polymerization. Because of its dimethylamino- ethyl fragment, it can act as an electron donor like TEA when it is present with electron acceptor molecules '). Moreover, this monomer has the additional advantage that its water-soluble homopolymer is a good surface tension modificator 6*7). For this reason 0 1991, Hiithig & Wepf Verlag, Base1 CCC 0173-2803/91/$01 .W