A novel approach is presented for the controlled intramolecular collapse of linear polymer chains to give well-defined single-molecule nanoparticles whose structure is directly related to the original linear polymer. By employing a combination of living free radical polymerization and benzocyclobutene (BCB) chemistry, nanoparticles can be routinely prepared in multigram quantities with the size being accurately controlled by either the initial degree of polymerization of the linear chain or the level of incorporation of the BCB coupling groups. The latter also allows the cross-link density of the final nanoparticles to be manipulated. In analogy with dendritic macromolecules, a significant reduction of up to 75% in the hydrodynamic volume is observed on going from the starting random coil linear chains to the corresponding nanoparticles. The facile nature of the living free radical process also permits wide variation in monomer selection and functional group incorporation and allows novel macromolecular architectures to be prepared. Furthermore, the use of block copolymers functionalized with benzocyclobutene groups in only one of the blocks gives, after intramolecular collapse, a hybrid architecture in which a single linear polymer chain is attached to the globular nanoparticle.

Three-dimensional ceramic nanostructured films were produced from silicon-containing triblock copolymer films exhibiting the double gyroid and inverse double gyroid morphologies (space group Ia3d). A one-step room-temperature oxidation process that used ozonolysis and ultraviolet irradiation effected both the selective removal of the hydrocarbon block and the conversion of the silicon-containing block to a silicon oxycarbide ceramic stable to 400 degrees C. Depending on the relative volume fraction of the hydrocarbon block to the silicon- containing block, either nanoporous or nanorelief structures were fabricated with calculated interfacial areas of approximately 40 square meters per gram and pore or strut sizes of approximately 20 nanometers.

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The synthesis and homo- and copolymerization of new cyclic esters containing protected functional groups (hydroxyl, bishydroxyl, amino, and carboxyl) are described. Each of the ε-caprolactone derivatives was generated by the Baeyer−Villiger oxidation of the corresponding cyclohexanone derivative. Monoprotection of 1,4-cyclohexanediol by benzylation or esterification was accomplished in moderate yields by reaction of benzyl bromide or 2,2‘-bis(phenyldioxymethyl)propionyl chloride. Each could be oxidized with pyridinium chlorochromate to yield the respective protected hydroxyl and bis(hydroxyl) functional cyclohexanones. The benzyl ether and benzyl ester protecting groups are readily removed by catalytic hydrogenolysis using Pd/C. Alternatively, ethyl-4-ketocyclohexylcarboxylate was hydrolyzed, and the free carboxylic acid was reesterified to the benzyl or tert-butyl 4-ketocyclohexylcarboxylate by esterification with either benzyl bromide or tert-butyl alcohol. These protecting groups were chosen because they are readily cleaved to the respective carboxylic acids under mild conditions. The aza-cyclohexanone derivative was produced from the commercially available ethylene ketal of 4-piperidone by acetylation with trifluoroacetic anhydride followed by transketalization using p-toluenesulfonic acid in excess acetone. The trifluoroacetyl protecting group is easily removed by NaBH4 reduction. Polymerization of the new monomers was accomplished either in bulk (110 °C) initiated from benzyl 2,2‘-bis(hydroxymethyl)propionate in the presence of stanneous 2-ethyl hexanoate (Sn(Oct)2) or from Al(O i Pr)3 in toluene (0 °C), yielding polymers close to their targeted molecular weights (5000−15 000) with modestly narrow polydispersities (1.20−1.35). Removal of the protecting groups on the aliphatic polyesters yielded the functionalized polymers.

Multilayer nanoporous films generated by a layer‐by‐layer spin‐on method are presented (see Figure). Precise control of the porosity of the individual layers that comprise the multilayer structure is demonstrated. Due to the simplicity of this fabrication method a wide range of potential applications in the areas of separation science, biotechnology, optics etc. are envisaged.