A series of “H-shaped” organic dimers （azobenzene derivatives） exhibit linear absorption red shift compared with their corresponding monomers experimentally. Dipolar interaction model is not appropriate for the az...A series of “H-shaped” organic dimers （azobenzene derivatives） exhibit linear absorption red shift compared with their corresponding monomers experimentally. Dipolar interaction model is not appropriate for the azobenzene derivatives due to the small distance between two “D-π-A” chains. Energy transfer model is suggested for explanation of the absorption red shift. Two necessary conditions for energy transfer were verified. In addition, bi-exponential florescence-delay behavior of the dimer as well as Bella＇s quantum chemistry calculation shows evidence of energy transfer.展开更多
A novel polyelectrolyte PNANT functionalized with electron donor-acceptor type azobenzene chromophores has been synthesized through post-polymerization azo coupling reaction and characterized by 1H-NMR,FTIR and UV-Vis...A novel polyelectrolyte PNANT functionalized with electron donor-acceptor type azobenzene chromophores has been synthesized through post-polymerization azo coupling reaction and characterized by 1H-NMR,FTIR and UV-Vis spectroscopy.The degree of functionalization (DF) of PNANT was 20% measured by elemental analysis.The degree of polymerization and its distribution were determined by GPC to be X n=251 with a polydispersion index 1.53.A glass transition temperature of 119℃ was observed from DSC thermogram. H-aggregation of azo chromophores of PNANT in spin-coated film and self-assembled film were detected from UV-Vis spectra,and the degree of H-aggregation of PNANT in the self-assembled film was found to be higher than that in the spin-coated film.Dichroism was optically induced in the spin-coated film and self-assembled film upon the irradiation of a polarized Ar + laser beam at 488 nm.The orientational order parameter obtained was 0.15 for spin-coated film and 0.07 for the self-assembled film.The resulting dichroism detected by UV-Vis spectra exhibited long-term stability.展开更多
文摘A series of “H-shaped” organic dimers （azobenzene derivatives） exhibit linear absorption red shift compared with their corresponding monomers experimentally. Dipolar interaction model is not appropriate for the azobenzene derivatives due to the small distance between two “D-π-A” chains. Energy transfer model is suggested for explanation of the absorption red shift. Two necessary conditions for energy transfer were verified. In addition, bi-exponential florescence-delay behavior of the dimer as well as Bella＇s quantum chemistry calculation shows evidence of energy transfer.
文摘A novel polyelectrolyte PNANT functionalized with electron donor-acceptor type azobenzene chromophores has been synthesized through post-polymerization azo coupling reaction and characterized by 1H-NMR,FTIR and UV-Vis spectroscopy.The degree of functionalization (DF) of PNANT was 20% measured by elemental analysis.The degree of polymerization and its distribution were determined by GPC to be X n=251 with a polydispersion index 1.53.A glass transition temperature of 119℃ was observed from DSC thermogram. H-aggregation of azo chromophores of PNANT in spin-coated film and self-assembled film were detected from UV-Vis spectra,and the degree of H-aggregation of PNANT in the self-assembled film was found to be higher than that in the spin-coated film.Dichroism was optically induced in the spin-coated film and self-assembled film upon the irradiation of a polarized Ar + laser beam at 488 nm.The orientational order parameter obtained was 0.15 for spin-coated film and 0.07 for the self-assembled film.The resulting dichroism detected by UV-Vis spectra exhibited long-term stability.
