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The patterning of surfaces on the nanometer scale is desirable for a variety of applications ranging from membranes to magnetic data storage.[1±4] Block copolymers provide a very promising route to this goal since they self-assemble into ordered arrays of nanostructures, [5±10] where the size is dictated by the molecular weight, and the type of morphology depends on the volume fractions of the blocks. However, control over domain orientation and lateral order of these arrays in thin films has been a challenge. Preferential wetting of a surface by one of the blocks typically results in the orientation of the copolymer microdomains parallel to the substrate, and the film thickness is quantized by the equilibrium period, L 0 . As the film thickness (D) approaches L 0 , the orientation of the microdomains becomes increasingly dictated by the strength of interfacial interactions and the commensurability of L 0 in relation to D. [11] In the case of a confined thin film, incommensurability of L 0 causes either a stretching or compression of the period or a reorientation of the structure normal to the surface. In thin films where the surface is not confined, control over the interfacial interactions has provided a simple route to control the orientation.[12] For thicker films, external fields (i.e., an electric field) have proven to be very effective in controlling the orientation of the microdomains. [13,14] Here, the spontaneous ordering of cylindrical microdomains in thin films of a metal-containing polyferrocene block copolymer perpendicular to a substrate surface is demonstrated. In addition, the pyrolysis of the ordered films to generate patterned arrays of ceramic nanostructures is described.Most studies of block copolymer self-assembly performed to date have focused on organic materials. Metal-containing block copolymers offer additional opportunities for the creation of functional nanostructured materials. [15,16] In this study, the microphase separation in thin films of an amorphous organic±organometallic block copolymer is discussed. Asymmetric poly(styrene-b-ferrocenylethylmethylsilane) block copolymers (PS 374 -b-PFS 45 , number average molecular weight, M n = 52 000 g mol ±1 , polydispersity index (PDI) = 1.21, PS volume fraction of 0.806) having cylindrical domains of PFS block in a PS matrix were studied. The copolymers were prepared by sequential anionic ring-opening polymerization (ROP) as described previously. [17,18] The T g of the PFS block is 19 C, whereas the T g of the PS block is~100 C. This contrasts with symmetrically substituted polyferrocenylsilanes, where the T g of the PFS block is significantly higher and the PFS block crystallizes. Both perturb microphase separation. [19±21] Small-angle X-ray scattering (SAXS) studies of a thermally annealed bulk sample of PS 374 -b-PFS 45 gave a scattering pattern consistent with a cylindrical morphology with a period of 33 nm, as shown in Figure 1. A series of PS 374 -b-PFS 45 films were prepared by spin coating the diblock copolymer onto silicon waf...

A novel and convenient route to the first poly(ferrocenylsilanes) with alkoxy and aryloxy substituents at silicon is reported. The reaction sequence involves (i) unexpectedly facile and clean halogen replacement at the bridging atom of a readily accessible dichlorosilyl-bridged [1]ferrocenophane Fe(η-C5H4)2SiCl2 (3) by OR groups via reactions with aliphatic alcohols and phenols in the presence of an HCl acceptor and (ii) thermal or transition metal-catalyzed ring-opening polymerization of the new [1]ferrocenophanes of structure Fe(η-C5H4)2Si(OR)2 (4). This allows the preparation of high molecular weight poly(ferrocenylsilanes) [Fe(η-C5H4)2Si(OR)2] n with side group substituents such as short chain alkoxy groups (5a − 5b, R = OMe, OEt), fluorinated ethoxy groups (5c, R = OCH2CF3), long chain alkoxy groups (5d − 5 g, R = OBu, OHex, OC12H25, OC18H37), and aryloxy substituents (5h, 5i, and 5k, R = OPh, OPh-p-tBu, OPh-p-tBu, OPh-p-Ph) at silicon. The molecular structures of the [1]ferrocenophane monomers 4a and 4j have been studied by single-crystal X-ray diffraction, and these species possess strained structures with tilt angles between the planes of the cyclopentadienyl ligands of 18−19°. The new poly(ferrocenylsilanes) possess a wide range of glass transition temperatures (T g = −51° (5e) to 97 °C (5k)) and the materials with long chain (OC12 (5f) or OC18 (5g)) alkoxy groups crystallize and exhibit melt transitions (T m) at −30 and +32 °C, respectively. Wide-angle X-ray scattering studies of 5g suggest a lamellar structure with interdigitated side groups. Cyclic voltammetry studies of the selected poly(ferrocenylsilanes) 5a and 5i show the characteristic two-wave pattern for poly(ferrocenes) with interacting iron atoms with a redox coupling ΔE = ca. 0.22 V.

Investigations on a series of crosslinked poly(ferrocenylsilane) networks that have been prepared via the ring‐opening copolymerization of the silicon‐bridged [1]ferrocenophane fcSiMe2 (fc = Fe(η‐C5H4)2) with controlled amounts of a spirocyclic [1]ferrocenophane fcSi(CH2)3 are reported. These crosslinked poly(ferrocenylsilane)s have improved thermal stability relative to their linear counterparts. The swelling response was investigated as a function of temperature, solvent and crosslink density. As expected, the degree of crosslinking had a dramatic effect on the swelling in various media. From swelling measurements in a variety of liquids, it was determined that the best solvents for poly(ferrocenyldimethylsilane) are THF, chloroform, and dichloromethane. The solubility parameter (δ) for the linear homopolymer was found to be 18.7(7) MPa1/2. Reversible electrochemical oxidation of the gel was observed at oxidation potentials greater than 450 mV (vs Ag/AgCl), consistent with the oxidation potential of the linear homopolymer, and an intervalence charge transfer band was detected at 1300 nm for the partially oxidized material.