Highly efficient two-photon initiated polymerization in solvent by using a novel two-photon chromophore and co-initiators

摘要

Highly efficient two-photon initiated polymerization in solvent was carried out in a three-component system,which consisted of a novel D-pi-A-pi-D type chromophore (1 or 2,respectively),the co-initiator,2,6-diisopropyl-N,N-dimethylaniline (DDA)and diphenyliodoinum salt,Ph_2I~+PF_6~-(PIP).We measured the quasi two-photon polymerization rates(R_p)based on scanning speed and the width of the written protruding line.Polymerization rates of the chromophore 1 and 2 were found to be 113 mum~3 s~(-1)and 157 mum~3 s~(-1)in the case of the laser power 4.5 mW at 820 nm (pulse width:85 fs,repetition rate 82 MHz )respectively.In order to estimate the mechanism of the photochemical reaction,the change of UV absorption of the three-component system,T-T transient absorption and the cyclic voltammetry(CV)of the novel chromophores were measured.Correlated with the CV,we interpreted that highly efficient electron transfer between DDA and the chromophore contributed to the long-lived radical cations of the chromophore.As a result,the generation of both DDA radicals and phenyl radicals was ascribed to high sensitivity in TPIP.