Discogen−DNA Complex Films at Air−Water and Air−Solid Interfaces
- Alpana Nayak
- K. A. Suresh
View Author Information Cite this: J. Phys. Chem. B 2008, 112, 10, 2930–2936Publication Date:February 19, 2008 https://doi.org/10.1021/jp710084q
Abstract
We have studied films of an ionic discogenic (discotic mesogenic) molecule (pyridinium salt tethered with hexaalkoxytriphenylene (PyTp)) and DNA complex at air−water (A−W) and air−solid interfaces. We have formed an PyTp monolayer on an aqueous subphase containing a small amount of DNA to obtain a PyTp−DNA complex at the A−W interface. Compared to the pure PyTp monolayer, the PyTp−DNA complex monolayer exhibits a higher collapse pressure and lower limiting area, indicating condensation and better stability. A Brewster angle microscope was used for in situ observation of the morphology of the film at the A−W interface. The PyTp−DNA complex films on silicon wafers were prepared using the Langmuir−Blodgett (LB) technique. We find that several tens of layers of the PyTp−DNA complex monolayer can be transferred with good efficiency. Fourier transform infrared spectroscopy studies confirm the presence of DNA in the LB films of the PyTp−DNA complex. Nanoindentation measurements using atomic force microscope reveal that the PyTp−DNA complex films are about two times harder as compared to the pure PyTp films.