Monolayer of octadecylamine（ODA） and salmon sperm DNA or salmon sperm DNA-Cd complex were studied on air-water interface by π-A isotherm. After being co-transferred onto substrates by Langmuir-Blodgett technique, atomic force microscope（AFM） measurements show the DNA molecules are packed into lines in the film, due to the interactions between the ODA and DNA molecules. By exposing the ODA and DNA-Cd complex LB film to H2S, needle-like CdS nanoparticles were formed along the DNA lines as characterized by transmission electron microscope（TEM）. Electron diffraction（ED） image indicates that the so prepared needle-like CdS is a new kind of nanostructured materials.
DNA/octadecylamine(ODA) monolayers were transferred onto silicon substrates and the morphologies of the monolayers were investigated by Atomic Force Microscope(AFM). AFM images show that the morphologies of DNA dissolved in pure water are very different from those of DNA dissolved in the NaCl solution. When DNA molecules are dissovled in pure water, they will form ball-like structure in the monolayer. When the DNA molecules are dissolved in NaCl solution, they will form bunch lines. This DNA line offers a valuable template to direct the formation of unique inorganic nanomaterials.
