1335044-85-3Relevant academic research and scientific papers
Photoinduced self-structured surface pattern on a molecular azo glass film: Structure-property relationship and wavelength correlation
Wang, Xiaolin,Yin, Jianjun,Wang, Xiaogong
, p. 12666 - 12676 (2011)
In this study, three series of star-shaped molecular azo glasses were synthesized, and self-structured surface pattern formation on the azo compound films was studied by laser irradiation at different wavelengths. The molecular azo glasses were synthesized from three core precursors (Tr-AN, Tr-35AN, Tr-H35AN), which were prepared by ring-opening reactions between 1,3,5-triglycidyl isocyanurate and corresponding aniline derivatives. The star-shaped azo compounds were obtained through azo-coupling reactions between the core precursors and diazonium salts of 4-chloroaniline, 4-aminobenzonitrile, and 4-nitroaniline, respectively. By using the two-step reaction scheme, three series of azo compounds with different structures were obtained. The core precursors and azo compounds were characterized by using 1H NMR, FT-IR, UV-vis, mass spectrometry, and thermal analyses. The self-structured surface pattern formation on films of the azo compounds was studied by irradiating the azo compound films with a normal-incident laser beam at different wavelengths (488, 532, and 589 nm). The results show that the photoinduced surface pattern formation behavior is closely related to the structure of the azo compounds, excitation wavelength, and light polarization conditions. The absorption band position of the π-π* transition is mainly determined by the electron-withdrawing groups on the azo chromophores. When the excitation wavelength is between λmax and the band tail at the longer wavelength side, the self-structured surface patterns can be more efficiently induced to form on the films. The 3,5-dimethyl substitution on azo chromophores inhibits the surface pattern formation for certain excitation wavelengths. Increasing molecular interaction also shows an effect of restraining the surface pattern formation. The irradiations with linearly and circularly polarized light cause significant differences in the alignment manner of the pillarlike structures and their saturated height.
Self-structured surface patterns on molecular Azo glass films induced by laser light irradiation
Yin, Jianjun,Ye, Gang,Wang, Xiaogong
experimental part, p. 6755 - 6761 (2011/01/04)
In this work, formation of photoinduced self-structured surface pattern and its correlation with chromophoric structures were studied by using a series of star-shaped azo compounds, which exist as stable molecular glass at room temperature. For the synthesis, a star-shaped precursor (Tr-AN) was prepared by a ring-open reaction between 1, 3, 5-triglycidyl isocyanurate and N-methylaniline. The star-shaped azo compounds were then synthesized through azo-coupling reactions between the precursor and diazonium salts of 4-nitroaniline, 2-methyl-4-nitroaniline, and 4-aminobenzonitrile, respectively. Through these steps, three azo compounds were obtained to bear different donor-acceptor type azo chromophores at the peripheral positions. The formation of the photoinduced self-structured patterns was investigated by irradiating solid thin films of the molecular azo glass with a uniform laser beam (532 nm, 200 mW/cm2) at normal incidence. For comparison, formation of surface-relief-gratings (SRGs) was also investigated by exposing the thin films to an interference pattern of the laser beams (532 nm, 80 mW/cm2). The results show that SRGs can be inscribed on the films of all three star-shaped azo compounds, but self-structured surface patterns is only observed on film of the azo compound containing 4-cyanoazobenzene moieties (Tr-AZ-CN) under the same irradiation condition. The electron-withdrawing groups, which control the absorption band position, show a significant influence on both the self-structured pattern formation and SRG inscription rate. Under proper experimental conditions, both self-structured surface pattern and SRG can simultaneously be observed on the Tr-AZ-CN films. The observations can lead to a deeper understanding of the photoinduced effects, especially their correlation with molecular structures.
