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Conductive microrods were prepared by evaporation-induced self-assembly (EISA) and subsequent polymerization of a novel, self-assembling molecule with pyrrole end groups. The newly synthesized selfassembling molecule of N91,N96-bis(3-(1-pyrrolyl)propanoyl) hexanedihydrazide self-assembled from a dilute solution into microrods. Pyrrole ring stacking was the key driving force inducing molecular selforganization to microrods. After the self-assembly, the pyrrole groups on the surface of the microrods were chemically polymerized to make the microrod conductive. The electrical conductance of the polymerized microrods was comparable to that of other conducting polymer microrods. Analyses of the polymerized microrods confirmed that the polymerization took place only at the surface of the microrod assembly. This study proved the concept of self-assembly and polymerization to generate complex structured functional materials, and is valuable for the design of functional self-assembling molecules.

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A novel approach for characterization of non-conductive protein-immobilized nanoparticles using AC impedance spectroscopy combined with conductive atomic force microscopy was examined. As AC impedance spectroscopy can provide information on diverse electrical properties such as capacitance and inductance, it is applicable to the characterization of non-conductive substances. Several non-conductive protein-immobilized polystyrene nanoparticles were analyzed using AC impedance spectroscopy, and their impedance spectra were used as markers for nanoparticle identification. Analyses of impedance signals using an electrical circuit model established that the capacitance and inductance of each nanoparticle changed with the adsorbed protein and that impedance spectral differences were characteristic properties of the proteins. From this study, AC impedance spectroscopy was shown to be a useful tool for characterization of non-conductive nanoparticles and is expected to be applicable to the development of sensors for nanomaterials.

We achieved simultaneous mineralization and patterning of inorganic nanoparticles on micropatterns using peptide as a linker and perfluoropolyether (PFPE) as a passivating molecule. The peptide was used as a linker molecule immobilizing inorganic nanoparticles on the substrate and PFPE was exploited as a mask material preventing nanoparticle binding. These two substances were used as surface-modifying molecules for the positive and negative patterns, respectively. On the patterned surface, mineralization and selective deposition of inorganic nanoparticles (such as TiO2 and Cu2S) were achieved by exploiting the characteristics of the surface-modifying molecules. The aqueous precursors of inorganic sources were mineralized to the nanoparticles, and the mineralized nanoparticles were bound directly to the peptide-decorated positive pattern, while their deposition on the negative pattern was repelled because of the low surface energy of PFPE. The nanoparticle-bound surface was identified by making a sandwich structure with a fluorescece-decorated peptide and observing the surface topology. The nanoparticle layers retained their inherent electrical properties, suggesting potential applications in micro device fabrication. This study demonstrates that selective deposition of metallic and inorganic nanoparticles can be achieved with the use of PFPE and reactive peptides while keeping the original characteristics of the nanoparticles.