The novel organometallic−inorganic diblock copolymer, poly(ferrocenyldimethylsilane)-b-poly(dimethylsiloxane) (PFS-b-PDMS) (block ratio = 1.0:6.0) (M n = 35 100 g/mol with a narrow molecular weight distribution M w/M n = 1.10 based upon gel permeation chromatography in THF using polystyrene standards) forms long rodlike micelles in hexane solution. After the solvent was evaporated, transmission electron microscopy (TEM) and atomic force microscopy (AFM) showed that individual cylindrical micellar structures form with the iron-rich, organometallic PFS core encased in a sheath (corona) of PDMS. The block copolymer forms hexagonally packed cylinders in the bulk, and exposure to warm hexane causes the cylinders to disperse in the solvent. Both static and dynamic light scattering (SLS and DLS) were used to establish that the micelles are flexible rods which are stable in hexane even at 80 °C. The as-prepared sample possessed an aggregation number of ca. 2000 polymer molecules. Ultrasonication (60 W) in hexane led to the generation of short cylinders with an aggregation number of ca. 700. Since PFS can be oxidized to a semiconductive state and PDMS is an insulator, these rodlike micellar structures have the potential to function as nanoscale self-insulated wires.

Self‐assembly of block copolymers with incompatible segments is known to generate a variety of different morphologies, and provides an attractive, alternative route to nanostructures. The authors describe some of their recent collaborative work on novel organometallic nanostructures made possible by the recent synthetic access to poly(ferrocene) block copolymers (see Figure and also the cover).

A non-covalent approach to debundle single wall carbon nanotubes using a biocompatible chitosan-derivative, namely N-octyl-O-sulfate chitosan (NOSC), was investigated. The resulting stable dispersions were characterised by Raman spectroscopy, UV-Vis spectroscopy, atomic force microscopy (AFM), transmission electron microscopy (TEM) and zeta-potential measurements. Both AFM and TEM studies revealed the presence of individual carbon nanotubes wrapped with the polymer (diameters up to 7 nm). Raman spectra showed radial breathing mode frequency shifts, after the addition of NOSC, due to the wrapping of the biomolecules onto the graphitic sidewalls. Molecular modelling studies were employed to investigate the mode of binding of the NOSC chains to the surface of the nanotubes. In agreement with the experiments, modelling studies predicted that the wrapped tube has a maximum thickness of approximately 7 nm. Studies on the anticoagulant properties of these complexes revealed that NOSC coated SWCNTs exhibit similar activity to the polymer alone, this property would eliminate the risk for SWCNTs to induce coagulation as a host reaction process when used in vivo.

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We have previously demonstrated that chitosan derivative N-octyl-O-sulfate chitosan (NOSC), which presents important pharmacological properties, can suspend single walled carbon nanotubes (SWNTs) up to 20 times more effectively than other chitosan derivatives in an aqueous environment. In an attempt to further investigate the impact of different molecular weights of chitosan to the solubilization and anticoagulant properties of these hybrids an array of NOSC derivatives varying their molecular weight (low, medium and high respectively) was synthesised and characterised by means of FT-IR spectroscopy, NMR spectroscopy and thermal gravimetric analysis (TGA). Microwave and nitric acid purified SWNTs, characterised by FT-IR spectroscopy, transmission electron microscopy (TEM) and Raman spectroscopy, were colloidally stabilised by these polymers and their anticoagulant activity was assessed. The results revealed that the low molecular weight NOSC coated SWNTs exhibit the highest activity when 0.5 mg mL(-1) NOSC solutions are used, activity which is similar to that of the free polymer. Preliminary studies by exposure of these hybrids to Brine Shrimp (Artemia) cysts revealed no effect on the viability of sub-adult Artemia. Our findings suggest the possibility of tailoring these nanomaterials to bear the required properties for application as biocompatible building blocks for nanodevices including biosensors and biomaterials.