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The orientation and structural characterization of the ultrathin film of azobenzene-containing amphiphilic compound, C_ 12AzoNaph(1,4)C_6N +Br -, were studied in the present study. The compound can form a stable monolayer with sodium dextrin sulfate(SDS) by means of electrostatic interaction. Fourier-transform infrared(FT-IR) and near-infrared surface-enhanced Raman scattering(NIR-SERS) spectroscopies were used to study the orientation and characterize the structure of the Langmuir-Blodgett(LB) film and the dipping film. The FT-IR spectra indicate that the alkyl tail is nearly perpendicular to the substrate surface without any aggregation and adopts largely trans-zigzag conformation in the LB film. The NIR-SERS spectra demonstrate that the chromorphoric part in C_ 12AzoNaph(1,4)C_6N +Br is also nearly perpendicular to the surface of silver substrate both in the dipping film and the LB film. A new “sandwiched system” model was designed to investigate the orientation and structural characterization of the chromophoric part in the multi-monolayer LB films on the non-SERS active substrate. The SERS mechanism of the “sandwiched system” is discussed in the present paper.
The orientation and structural characterization of the ultrathin film of azobenzene-containing amphiphilic compound, C-12AzoNaph (1,4) C_6N + Br - studied were the present study. The compound can form a stable monolayer with sodium dextrin sulfate (SDS) by Fourier-transform infrared (FT-IR) and near-infrared surface-enhanced Raman scattering (NIR-SERS) spectroscopies were used to study the orientation and characterize the structure of the Langmuir-Blodgett (LB) film and the The FT-IR spectra indicate that the alkyl tail is nearly perpendicular to the substrate surface without any aggregation and dominant largely trans-zigzag conformation in the LB film. The NIR-SERS spectra demonstrate that the chromorphoric part in C-12Azo Naph (1 , 4) C_6N + Br is also substantially perpendicular to the surface of silver substrate both in the dipping film and the LB film. A new “sandwiched system ” model was designed to investigate the orientation and structur al characterization of the chromophoric part in the multi-monolayer LB films on the non-SERS active substrate. The SERS mechanism of the “sandwiched system” is discussed in the present paper.