Fluorescent dye-labeled polymers carrying triphenylamine, styrene, or acrylate pendant groups

An alkoxyamine initiator carrying a perylene bisimide unit suitable for the nitroxide mediated controlled radical polymerization of different monomers was synthesized. The synthesis, characterization, and properties of a series of polymers obtained from monomers such as 4-vinyltriphenylamine, styrene, and different acrylates using this initiator are described. The controlled nature of the polymerization was demonstrated by time-dependent measurements of the conversion and the molecular weight. The incorporation of the single fluorescent unit to the polymer chain end was verified by MALDI-TOF MS. The perylene bisimide acts as an electron acceptor with a strong fluorescence. Since 4-vinyltriphenylamine is a donor monomer, the resulting polymers exhibit photoluminescence quenching due to electron transfer between the donor polymer chain and the acceptor moiety. The perylene bisimide moiety shows aggregation via pi-pi stacking which was studied using UV-vis and fluorescence spectroscopy. By controlling the polymer chain length, the stacking of the perylene bisimide can be controlled. The LUMO and HOMO levels of the perylene bisimide initiator and the dye-labeled polymer were determined by cyclic voltammetry as -3.7 and -6.0 eV, respectively. With this approach tailor-made fluorescent dye-labeled polymers with desired architecture, low polydispersity, and controlled molecular weight can be obtained as model systems for electron and energy transfer studies.