Novel D–π3–(A)1–3 multibranched chromophores as an efficient two-photon-induced polymerization initiator

The ability of novel branched chromophores that contained a triphenylamine group as donor, naphthalene as π-bridge and pyridyl as acceptor group, to act as two-photon absorption and two-photon induced polymerization initiators were investigated. Linear and nonlinear optical spectra revealed that chromophores with large dipolar moment change gave strong intramolecular charge-transfer characteristics that exhibited enhanced two-photon absorption cross-section. A variety of micro-objects were fabricated, using an acrylate matrix, that contained the novel chromophores as two-photon induced polymerization initiator. Molecular energy levels, electrochemistry and linear absorption spectra, as well as one-photon fluorescence quenching measurements supported the hypothesis that two-photon induced polymerization proceeds via intermolecular charge-transfer from initiator to monomer and, that the chromophore firstly generates the exciton via two-photon absorption and then transfers charge to the acrylate monomer which then polymerises.