Type I, bovine skin collagen was allowed to gel in the presence of various concentrations of a carbon nanotube material covered with a polystyrene/polyaniline copolymer, called a carbon nanobrush, CNB. The rate of collagen gelation was enhanced by the presence of the CNB in a dose dependent manner. The extent of collagen gelation was due to the concentration of collagen and not the amount of CNB. Collagen D-periodicity, and average fibril diameter were unchanged by the CNB material as seen in transmission electron micrographs. Gel tensile strength was reduced by the presence of the the CNB in a dose related manner. The collagen-CNB mixture may have a role in the repair and reconstruction of wounds or degenerated connective tissue.
We report a novel method for synthesizing electrically conductive nano-brush (CNB) by physical grafting of organic conducting polymers on carbon nano tubes (CNT). The objective for this synthesis is to produce nano tubes having a CNT stem coated with flexible electronic conducting polymers. The nano-brush is to be blended into common polymers (e.g. epoxy, polyurethane, and poly(vinyl alcohol)) to form electrically conductive composite material. The flexible organic conducting polymer in CNB is a potentially sensitive electronic probe for mechanically induced nano-deformation of the composite because it is molecularly entangled with the host polymers. The electrical networks of CNB embedded in polymeric composites are potentially useful as in situ sensors for monitoring material deformation with an unprecedented level of sensitivity. The composite material is “smart” in the sense that it self-reports the structural “health” before load induced material failure.Our method for grafting conducting polymer does not require chemical reactions with the surface atoms of the carbon nano tube. We used physical adsorption to graft electronic conducting polymer to CNT. We first synthesized a water-soluble electronic conducting polymer which is a molecular complex between poly(acrylic acid) and polyaniline. The CNT solid were dispersed and un-bundled by sonnication in the conducting polymer solution. Due to the high affinity between CNT and the conducting polymer, the surface of CNT can be fully covered with the conducting polymer. The experimental data is consistent with a structure of nano brush with high density of conducting polymers grafted on the CNT surface.
Friedel-Crafts acetylation of adducts between 1,8-dimethoxyanthracene and maleic anhydride or dimethyl maleate proceeds with a strong preference toward the syn diastereomer. This stereoselectivity is especially prominent for the anhydride counterpart. Dependence of the observed selectivity on the adduct structure is rationalized by the analysis of computed HOMO energies of the reactants and relative energies of the intermediate σ-complexes. The pos-
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