Polyferrocenylsilane block copolymers: Nanotubes and nanowires through self-assembly

Abstract

Polyferrocenyldimethylsilane (PFS) diblock copolymers with polyisoprene (PFS-PI) or with polydimethylsiloxane (PFS-PDMS) self-assemble in simple alkane solvents to form what appear by TEM to be dense flexible cylinders (nanowires) or "nanotube-like" structures. Typical widths are on the order of 20 to 30 nm, with variable lengths often greater than 10 μm. The structures that form, and the dimensions of the "tube-like" structures or wires, depend upon the composition of the polymers and the lengths of the blocks. Light scattering experiments show that the PFS-PDMS (block ratio 1:12) solutions aged at 25 °C contain long thin objects 950 nm in length. These structures probably rearrange on the TEM grid as the solvent evaporates to form elongated structures. Establishing a mechanistic connection between the objects present in solution and those seen in the TEM images, as well as understanding the factors that lead to these unusual self-assembled structures, remain a challenge. © Springer-Verlag Berlin Heidelberg 2006.