A method of fabricating gold nanoparticle coated polypyrrole(PPy) tubules was developed by coating citrate-reduced gold nanoparticles on polypyrrole tubule templates. The PPy tubules were grown uniformly with a diameter of 200 nm, which is in agreement with that of the pore size of the microporous polycarbonate(PC) membrane template. The Au particles formed by citrate reduction can be deposited on the surface of the PPy tubules. Electrostatic interaction between gold nanoparticles and PPy tubules was used as a driving force for this assembly process. The TEM image shows that a submonolayer coating of the particles was formed.The Au nanoparticle coated PPy tubules was applied to hold and analyze trace molecules as signal-enhancing cuvettes for Raman spectroscopy. Their SERS-activity was tested with Rhodamine B. In contrast with the neat PPy tubule, the Raman scattering of trace Rhodamine B on the Au nanoparticle-coated tubule was enhanced by a factor of 105. This work develops a cheap and convenient method to fabricate gold nanocrystal coated PPy tubule and its application as fabrication of Raman signal enhancing cuvette.
A bolaform amphiphile(BP-15) bearing biphenyl group and long spacers of alkyl chains was synthesized. In-situ AFM studies indicate that the amphiphile can form two kinds of surface aggregates with different morphologies depending on solution concentration: short-range ordered cylindrical surface micelles at the lower concentration and flat domains at the higher concentration. These results agree well with the two critical micelle concentrations in bulk solution as determined by the concentration-dependent conductivity.
