Showing papers in "Chemistry of Materials in 1989"

Chemical Vapor Deposition of Copper and Copper Oxide Thin Films from Copper(I) tert-Butoxide

Abstract: The low-temperature deposition of thin-film materials from molecular transition-metal precursors is an area of rapidly growing interest. We now describe the deposition of copper-containing films from copper(I) tert-butoxide tetramer, (Cu(O-t-Bu)){sub 4}, which was chosen because it is one of the more volatile molecular derivatives of copper known. These results are related to efforts directed toward the chemical vapor deposition of thin films of the new copper oxide based high-temperature superconductors.

Uniform colloidal zinc compounds of various morphologies

Abstract: The preparation of finely dispersed zinc compounds consisting of uniform particles is described. Aging at elevated temperatures ({approx} 90{degree}C) of aqueous solutions of zinc nitrate or zinc chloride in the presence of urea resulted in precipitation of uniform rodlike basic zinc carbonate particles. These solids show x-ray characteristics of crystalline hydrozincite. In the presence of sulfate ions amorphous spherical particles of narrow size distribution of the same chemical composition are generated. On calcination both kinds of solids change to zinc oxide yet retain the original shape. In the presence of NaH{sub 2}PO{sub 4} and urea, aqueous zinc salt solutions on aging yield rather uniform amorphous spherical zinc basic phosphate particles, which on calcination lose water.

Water-soluble self-doped 3-substituted polypyrroles

Abstract: The preparation of sodium sal& of 3-akyhdfomte pyrroles with various lengths of the alkyl chain (propyl-, butyl-, and hexylsulfonate) and their electrochemical polymerization to poly(3-alkylsulfonate pyrroles) are described. The low oxidation potential of the monomers allows a direct oxidative electrochemical polymerization, without additional conduction salts. The experimental conditions provide, for the first time, solid evidence of the existence of self-doped conducting polypyrroles. The polymers are characterized by spectroscopy (ETIR, W-vis-NIR, ESR, 'H NMR in D20 solution), X-ray diffraction, cyclic voltammetry, and elemental analyses. The covalently attached sulfonate groups act as counterions for the charged backbone. The charge carriers are mainly spinless bipolarons. The conductivities are in the range 0.fi-10-3 S/cm, the lower value referring to the hexyl chain. Indications are given for deviations from planarity of the main chain. The substituted polypyrroles are water soluble in the self-doped state. 'H NMR spectra of the aqueous solutions of self-doped polymers are discussed.

Potential dependence of the relative conductivity of poly(3-methylthiophene): electrochemical reduction in acetonitrile and liquid ammonia

Abstract: Relevant topics for Chemistry of Materials include both theoretical and experimental studies that focus on the preparation, characterization, processing, or understanding of materials with unusual or useful properties. Of particular importance are the originality, significance, overall quality, and completeness of the work as well as its relevance to both chemistry and materials science. The last of these considerations, in particular, serves to define the particular focus of this journal and the special niche that it seeks to fill among periodicals in materials science. Recognizing the international scope and the breadth of the subject, the Editorial Advisory Board of Chemistry of Materials has been selected to ensure a strong international representation as well as a broad perspective on the wide range of subjects in materials chemistry. Included on the Advisory Board are over sixty scientists and engineers from academic, industrial, and governmental laboratories in ten different countries. The articles scheduled for publication in the first few issues are illustrative of this broad, international perspective on materials chemistry. Among the topics covered are molecular and polymeric conductors, nonlinear optical materials, thin-film resists, various aspects of solid-state inorganic chemistry including high-T, superconductors, sol-gel processing, chemical vapor deposition, ceramic precursors, biosensors, colloid chemistry, electronic materials processing, heterogeneous