화학공학소재연구정보센터
Langmuir, Vol.18, No.16, 5971-5973, 2002
Formation of conjugated azomethine oligomers on quartz and silicon oxide surfaces
We describe a solution phase method to generate conjugated oligoazomethine assemblies on quartz and silicon oxide surfaces. The method is based on a controlled iminization reaction in which aromatic aldehydes and amines (1,4-terephthaldicarboxaldehyde, TPDA, and 1,4-phenylenediamine, PPDA) are sequentially assembled onto amino-functionalized substrates. Polarized attenuated total reflectance Fourier transform infrared spectroscopy and spectroscopic ellipsometry confirm monomer assembly on oxidized silicon surfaces. Using UV-visible spectroscopy with quartz substrates, we explored the roles of temperature, acid catalyst, and monomer concentration on rates of film formation. Arrhenius plots of observed rate constants yielded values for activation energies of 28 7,14 7, and 17 8 M mol(-1) for uncatalyzed TPDA, catalyzed TPDA and catalyzed PPDA assembly, respectively. Observed rate constants for TPDA assembly grew linearly with monomer concentration, while those for PPDA assembly were independent of monomer concentration. Fully formed films were found,to be remarkably stable to repeated sonication and exposure to solvents at elevated temperatures.