π-conjugated polymers such as polyaniline, polypyrrole and polythiophene, have been widely studied and applied in various fields because of their unique electronic, optical and catalytic properties. Thus, controlled fabrication and patterning of such polymers on a nanometer scale could provide new platform technologies, such as nanodevices and nanosensors. To further miniaturize structures, template-directed materials assemblies allows directly physical patterning when individual biomolecules with well-defined architectures are used as the templates.
Here, we describe a simple method for the fabricating highly aligned and integrated π-conjugated polymer nanowires with DNA templates. π-conjugated polymer, polyphenazasiline, having alkyl ammonium salts on the N atom (PPhenaz-TMA) could be organized along stretched and aligned DNA molecules on surfaces. The observed height (diameter) of DNA was <1 nm before treatment with PPhenaz-TMA but increased to 1.31±0.18 nm after treatment. We believe that the height increase after treatment is caused by polymer deposition. Furthermore, PPhenaz-TMA/DNA nanowires were stretched and aligned on surfaces, even when PPhenaz-TMA/ DNA complexes formed in solutions. It is interesting to note that PPhenaz-TMA with interparticle spacing was attached to DNA like beads. By using atomic force microscopy (AFM) and scanning near-field microscopy (SNOM), we discuss structural changes of PPhenaz-TMA/DNA nanowires before and after treatments of adequate oxidant or metal salts. |