Poly[(vinyloxy)cyclophosphazenes]

Self-Assembly of Hierarchical Structures Using Cyclotriphosphazene-Containing Poly(substituted methylene) Block Copolymers

The cyclotriphosphazene-substituted diazoacetate homopolymer (polyPNDA') (PNDA' = hexaphenoxy-substituted phosphazene-containing methylene) and a novel poly(substituted methylene) block copolymer, polyPNDA'-block-poly(hexyloxycarbonylmethylene) (polyPNDA'-b-polyHDA'), were synthesized, and the self-assembly behavior of these polymers was studied in detail. A hexagonally packed aggregated structure was observed in the self-assembled structure of polyPNDA', whereas a lamellar structure was observed in the microphase-separated nanoassembly of polyPNDA'-b-polyHDA'. These results indicate that a hierarchical structure composed of highly regular polyPNDA' nanoaggregates and the long-range microphase-separated polyPNDA' and polyHDA' domains had formed.

Pd-initiated controlled polymerization of diazoacetates with a bulky substituent: synthesis of well-defined homopolymers and block copolymers with narrow molecular weight distribution from cyclophosphazene-containing diazoacetates

Pd-initiated polymerization of cyclophosphazene-containing diazoacetates proceeded in a controlled manner.

Metallophosphazene precursor routes to the solid-state deposition of metallic and dielectric microstructures and nanostructures on Si and SiO2

We present a method for the preparation and deposition of metallic microstructures and nanostructures deposited on silicon and silica surfaces by pyrolysis in air at 800 degrees C of the corresponding metallophosphazene (cyclic or polymer). Atomic force microscopy studies reveal that the morphology is dependent on the polymeric or oligomeric nature of the phosphazene precursor, on the preparation method used, and on the silicon substrate surface (crystalline or amorphous) and its prior inductively couple plasma etching treatment. Microscale and nanoscale structures and high-surface-area thin films of gold, palladium, silver, and tin were successfully deposited from their respective newly synthesized precursors. The characteristic morphology of the deposited nanostructures resulted in varied roughness and increased surface area and was observed to be dependent on the precursor and the metal center. In contrast to island formation from noble metal precursors, we also report a coral of SnP(2)O(7) growth on Si and SiO(2) surfaces from the respective Sn polymer precursor, leaving a self-affine fractal structure with a well-defined roughness exponent that appears to be independent (within experimental error) of the average size of the islands. The nature of the precursor will be shown to influence the degree of surface features, and the mechanism of their formation is presented. The method reported here constitutes a new route to the deposition of single-crystal metallic, oxidic, and phosphate nanostructures and thin films on technologically relevant substrates.

Pendant cyclodicarbaphosphazatriene-containing monomers and polymers: synthesis, crystal structures and polymerization behavior of [NC(NMe2)]2[NP(O-C6H4-p-C6H4-p-CH=CH2)(X)], X = Cl, OCH2CF3, OC6H5, OC6H4-m-CH3, OC6H4-p-Br

The reaction of the dicarbaphosphazene, [NC(NMe(2))](2)[NPCl(2)] (2), with the sodium salt of 4-hydroxy-4'-vinylbiphenyl afforded the vinyl group containing monomer [NC(NMe(2))](2)[NP(Cl)(O-C(6)H(4)-p-C(6)H(4)-p-CH=CH(2))] (3). Replacement of the lone chlorine atom of 3 by oxygen nucleophiles gave [NC(NMe(2))](2)[NP(OR)(O-C(6)H(4)-p-C(6)H(4)-p-CH=CH(2))] [R = CH(2)CF(3) (4); C(6)H(5) (5); C(6)H(4)-m-CH(3) (6); C(6)H(4)-p-Br(7)]. The X-ray crystal structures of 3-7 reveal that all the cyclodicarbaphosphazenes have a planar N(3)PC(2) ring; the ring carbons are completely planar, while the geometry around phosphorus is pseudotetrahedral. The presence of weak intermolecular hydrogen bonding [C-H---X(Cl or Br), C-H---N, or C-H---pi] interactions in 3-7 leads to the formation of polymeric architectures in the solid-state. The monomers 4-7 can be polymerized by a free-radical initiator to afford the corresponding air-stable homopolymers 8-11. These have moderate molecular weights with polydispersity indices ranging from 1.33 to 1.58. All of these polymers have high glass transition temperatures and have excellent thermal stability.