Soluble Aromatic Polyamides and Copolyamides
Aramids have been known for their high heat resistance and high strength. The alkyl:aryl polyamides are derived from aliphatic primary and secondary diamines, cycloaliphatic secondary diamines, and...
Materials Literature
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Elastic scalar invariants in the theory of defective crystals
In the context of a continuum theory of crystals with defects, the elastic scalar invariants are functions of the lattice vectors and their spatial gradients which remain invariant under elastic changes of state. In particular, the lattice components of the dislocation density tensor are prototypical of elastic scalar…
On the origin of dynamic heterogeneities in glass-forming liquids
We employ classical Molecular Dynamics simulations to study the cooperative dynamics of two low molecular weight glass-formers, propylene carbonate and salol. The length scales of dynamic heterogeneities are estimated. After appropriate scaling both glass-formers display a similar temperature dependence of this length…
Monte Carlo and numerical self-consistent field study of end-tethered polymers in good solvent
We present a Monte Carlo (MC) and numerical self-consistent field (NSCF) study of end-tethered polymers in good solvent, for surface coverages found in most experiments. Properties of the system, including the layer thickness, are calculated as functions of the degree of polymerization and surface density of the chain…
Size and number density of precrystalline aggregates in lysozyme crystallization process
Using dynamic light scattering, we investigated supersaturated aqueous solutions of hen egg white lysozyme. We could observe the formation of aggregates only in solutions, from which crystals grew within a few days. The aggregates were grouped into smaller “units” and larger “clusters.” The units consisted of a few mo…
Synthesis of Acrylic Superabsorbents
Superabsorbent polymers (SAPs) are characterized by their ability to absorb and retain unusually large amounts of water and body fluids [1]. As these materials are dry substances and act as gelling...
Electronic structure and magnetic properties of high-spin octahedral Co(II) complexes: Co(II)(acac)2(H2O)2
An analysis of the electronic structure of the high-spin 3d7 Co(II) ion in the approximately octahedral Co(II)(acac)2(H2O)2 complex is presented in terms of crystal fields of descending symmetry from octahedral to orthorhombic. The energies and wave functions resulting from the interplay of these fields with the spin–…
Web-Structured Films of an Amphiphilic Polymer from Water in Oil Emulsion: Fabrication and Characterization
Fabrication of micro surface morphology of cell culture substrates is one of the current topics in biomaterials research. Recently we found that regular honeycomb structures with micrometer scale dimensions can be fabricated by simple casting of a dilute solution of amphiphilic polymers on solid substrates. The honeyc…
Biodegradable Polymers: Opportunities and Challenges
As we are approaching the 21st century, the plastics industry may be witnessing a paradigm shift—a move from an all-petroleum-based industrial economy to one that encompasses a broader base of mate...
Dynamic scaling in vacancy-mediated disordering
We consider the disordering dynamics of an interacting binary alloy with a small admixture of vacancies which mediate atom-atom exchanges. Starting from a perfectly phase-segregated state, the system is rapidly heated to a temperature in the disordered phase. A suitable disorder parameter, namely, the number of broken…
Role of Betaine as Foam Booster in the Presence of Silicone Oil Drops
Betaines (a particular class of amphoteric surfactants) are commonly used as foam boosters in various products to improve their foamability and foam stability. Foaming media often contain dispersed drops of silicone or hydrocarbon oil, which act as foam destruction agents (antifoams). A complementary set of experiment…
Thermodynamical fluctuations and photo-thermal shot noise in gravitational wave antennae
Thermodynamical fluctuations of temperature in mirrors of gravitational wave antennae are transformed through thermal expansion coefficient into additional noise. This source of noise, which may also be interpreted as fluctuations due to thermoelastic damping, may not be neglected and leads to the necessity to reexami…
Complementary packing of α‐helices in proteins
The packing of alpha-helices in proteins is restricted by both the principle of close packing and the chemical nature of side chains. As a result, (1) alpha-helical surfaces forming the interface should be complementary to each other, (2) hydrophobic stripes of the alpha-helices should fit together like pieces of a ji…
Photosensitive liposomes as ‘cages’ for laser‐triggered solute delivery: the effect of bilayer cholesterol on kinetics of solute release
Liposomes containing acyl chains incorporating azobenzene chromophores have been investigated as potential 'caging' agents for fast solute release. On photolysis, trapped marker dye can be released from gel-phase liposomes within milliseconds. Solute release is markedly sensitive to the presence of cholesterol in the…
Carbon nanotubes: From macromolecules to nanotechnology
Proceedings of the National Academy of Sciences (PNAS), a peer reviewed journal of the National Academy of Sciences (NAS) - an authoritative source of high-impact, original research that broadly spans the biological, physical, and social sciences.
Advances in Synthetic Metals: Twenty Years of Progress in Science and Technology
Preface (J. Friedel). Twenty years of synthetic metals - the role of synthesis (D. Marsitzky, K. Mullen). Twenty years of conducting polymers: from fundamental science to applications (M.D. McGehee et al.). The normal phase of quasi-one-dimensional organic superconductors (C. Bourbonnais, D. Jerome). Interplay of stru…
A Fermi Surface study of Ba$_{1-x}$K$_{x}$BiO$_{3}$
We present all electron computations of the 3D Fermi surfaces (FS's) in Ba$_{1-x}$K$_{x}$BiO$_{3}$ for a number of different compositions based on the selfconsistent Korringa-Kohn-Rostoker coherent-potential-approximation (KKR-CPA) approach for incorporating the effects of Ba/K substitution. By assuming a simple cubic…
Biomimetics: Materials fabrication through biology
Many multicellular organisms produce hard tissues such as bones, teeth, shells, skeletal units, and spicules (1). These hard tissues are biocomposites and incorporate both structural macromolecules (lipids, proteins, and polysaccharides) and minerals of, perhaps, 60 different kinds, including hydroxyapatite, calcium c…
External-Field-Induced Tricritical Point in a Fluctuation-Driven Nematic–Smectic-ATransition
We study theoretically the effect of an external field on the nematic--smectic- $A$ transition close to the tricritical point, where fluctuation effects govern the qualitative behavior of the transition. An external field suppresses nematic-director fluctuations by making them massive. For a fluctuation-driven first-o…
Inhomogeneous transport in heteroepitaxial La0.7Ca0.3MnO3/SrTiO3 multilayers
We have investigated the electrical transport properties of heteroepitaxial La0.7Ca0.3MnO3(LCMO)/SrTiO3 multilayers; as the LCMO layer thickness was varied from 25 to 2.5 nm, the metallic transition was suppressed and enhanced magnetoresistance extended over low temperatures. The results of transport and magnetic meas…