title: Discogen-DNA complex films at air-water and air-solid interfaces.
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.
authors.affiliation: Raman Research Institute, Sadashivanagar, Bangalore, India.
authors.forename: Alpana
authors.initials: A
authors.lastname: Nayak
authors.forename: K A
authors.initials: KA
authors.lastname: Suresh
mesh_terms: D000388:Air; D004247:DNA / Q000737:chemistry* / Q000648:ultrastructure; D004548:Elasticity; D018625:Microscopy, Atomic Force; D044367:Phase Transition; D017550:Spectroscopy, Fourier Transform Infrared; D013499:Surface Properties; D014867:Water / Q000737:chemistry*
chemical_list: D014867:Water; D004247:DNA