Materials Literature
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We investigated the structure of a low-bandgap conjugated polymer, polyisothianaphthene (PITN), with a joint experimental and theoretical approach. On the one hand, C-13 NMR measurements are performed on the polymer and on a series of model isothianaphthene molecules. These molecular compounds are designed and synthes…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPara-linked aromatic poly(amic ethyl esters): precursors to rodlike aromatic polyimides. 1. Synthesis and imidization studyKevin H. Becker and Hans Werner SchmidtCite this: Macromolecules 1992, 25, 25, 6784–6790Publication Date (Print):December 1, 1992Publication History Pub…
We study the dynamics of defects generated in free-standing films of liquid crystals following a thermal quench from the smectic-A phase to the smectic-C phase. The defects are type-1 disclinations, and the strain field between defect pairs is confined to 2\ensuremath{\pi} walls. We compare our observations with a phe…
Short-chain complexed poly-beta-hydroxybutyrate, 130-170 monomer units, is a ubiquitous constituent of cells, wherein it is usually associated with other macromolecules by multiple coordinate bonds, or by hydrogen bonding and hydrophobic interactions. This conserved PHB has been isolated from the plasma membranes of b…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSynthesis and characterization of novel cobalt aluminum cofacial porphyrins. First crystal and molecular structure of a heterobimetallic biphenylene pillared cofacial diporphyrinRoger Guilard, Michel Angel Lopez, Alain Tabard, Philippe Richard, Claude Lecomte, Stephane Brand…
Considerable progress has been made toward the goal of diamond synthesis by chemical vapor deposition (CVD). This progress consists of improved methods for synthesis and understanding how diamond is formed. The field has rapidly expanded with industrial consortia, international joint ventures, specialized journals, no…
Eighteen europium–nitrogen bonds are formed when a specially designed bis(terdentate) nitrogen-containing ligand L1 reacts with europium(III) perchlorate. In the resulting triple-helical dinuclear cation [Eu2L]6+ 1, the metals are coordinated to nine nitrogen atoms each, forming a slightly distorted tricapped trigonal…
Abstract This paper deals with the early stages of blend morphology development as occurs in a screw extruder. Using combinations of similar polymers (polystyrene and styrene‐butadiene copolymer) and dissimilar polymers (PS and EVA) as model systems, it has been concluded that during melting the scale of segregation b…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTCellulose acetate butyrate and poly(hydroxybutyrate-co-valerate) copolymer blendsCharles M. Buchanan, Steve C. Gedon, Alan W. White, and Matthew D. WoodCite this: Macromolecules 1992, 25, 26, 7373–7381Publication Date (Print):December 1, 1992Publication History Published onl…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTThe crystal/liquid interface: structure and properties from computer simulationBrian B. Laird and A. D. J. HaymetCite this: Chem. Rev. 1992, 92, 8, 1819–1837Publication Date (Print):December 1, 1992Publication History Published online1 May 2002Published inissue 1 December 19…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTFirst ferromagnetic interaction in a heteropoly complex: [CoII4O14(H2O)2(PW9O27)2]10-. Experiment and theory for intramolecular anisotropic exchange involving the four Co(II) atomsNieves Casan-Pastor, Julia Bas-Serra, Eugenio Coronado, Genevieve Pourroy, and Louis C. W. Bake…
Pseudomonas oleovorans is an adaptable, aerobic bacterium that can produce a wide range of storage polyesters (poly-β-hydroxyalkanoates, PHAs). With few exceptions, the PHAs obtained when this bacterium is grown with single organic substrates capable of polymer production are generally copolymers. With two different p…
Polyacrylic acid (PAA) has been chosen to stabilize BaTiO 3 powder in aqueous solution. Zeta potential studies show that the Ba‐rich particle surface is positively charged in the pH range from 2 to 11 without PAA. Adsorption of PAA decreases the zeta potential in acidic solution and changes the surface to a negative c…
Molecular dynamics (MD) studies of collision cascades have firmly established that, in addition to clusters of vacancies, clusters of self-interstitial atoms (SIAs) are formed within the cascade volume during the thermal spike phase of a cascade. These clusters are formed in a segregated fashion such that the vacancy-…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSynthesis and characterization of a superoxo complex of the dicobalt cofacial diporphyrin [(.mu.-O2)Co2(DPB)(1,5-diphenylimidazole)2][PF6], the structure of the parent dicobalt diporphyrin Co2(DPB), and a new synthesis of the free-base cofacial diporphyrin H4(DPB)James P. Co…
Recently, there has been amazing progress in the study of highly conductive polyacetylene. The advent of a metallic-conductive polyacetylene has overthrown the general view of the polymeric material. However, the conduction mechanism of the conductive polymer is as yet far from well understood. This review article cov…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTHighly efficient oxidation of alkanes and alkyl alcohols with heteroaromatic N-oxides catalyzed by ruthenium porphyrinsHiro Ohtake, Tsunehiko Higuchi, and Masaaki HirobeCite this: J. Am. Chem. Soc. 1992, 114, 26, 10660–10662Publication Date (Print):December 1, 1992Publicatio…
Molecular-dynamics simulation results are reported for systems of strongly interacting dipolar soft spheres. Calculations have been carried out along two isotherms and the structure of the liquid-crystal and solid phases obtained is described in detail. It is found that in addition to the ferroelectric nematic phase w…
Abstract HNBR rubbers, which are made by selective hydrogenation of the olefinic bonds of NBR rubbers, have been developed, because they show improved resistance towards heat and chemicals. In this study, two other properties are discussed that arise from the fact that HNBR rubbers are fairly alternating copolymers of…
Abstract Structural differences which occur on heating La-montmorillonite have been studied and compared with those for montmorillonite saturated with Na(I) and Li(I). Rehydration experiments show that La-montmorillonite swells after preheating up to 500°C. However, FT-IR spectra suggest partial migration of the La(II…