Organic semiconducting oligomers for use in thin film transistors.

We provide an overview of the basic concepts of scaling and dimensional analysis, followed by a review of some of the recent work on applying these concepts to modeling instrumented indentation measurements. Specifically, we examine conical and pyramidal indentation in elastic-plastic solids with power-law work-hardening, in power-law creep solids, and in linear viscoelastic materials. We show that the scaling approach to indentation modeling provides new insights into several basic questions in instrumented indentation, including, what information is contained in the indentation load-displacement curves? How does hardness depend on the mechanical properties and indenter geometry? What are the factors determining piling-up and sinking-in of surface profiles around indents? Can stress-strain relationships be obtained from indentation load-displacement curves? How to measure time dependent mechanical properties from indentation? How to detect or confirm indentation size effects? The scaling approach also helps organize knowledge and provides a framework for bridging micro- and macroscales. We hope that this review will accomplish two purposes: (1) introducing the basic concepts of scaling and dimensional analysis to materials scientists and engineers, and (2) providing a better understanding of instrumented indentation measurements.

Scaling, dimensional analysis, and indentation measurements

The objective of this article was to review the use of carbon black (CB) as a conductive filler in polymers and polymer blends. Important properties of CB related to its use in conducting polymers are discussed. The effects of polymer structure, molecular weight, surface tension, and processing conditions on electrical resistivity and physical properties of composites are discussed. Several percolation models applicable to CB/polymer blends are reviewed. Emphasis is placed on recent trends using polymer blends as the matrix to obtain conducting composites at a lower CB loading. A criterion for the distribution of CB in polymer blends is discussed. © 2002 Wiley Periodicals, Inc. Adv Polym Techn 21: 299–313, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/adv.10025

Carbon black filled conducting polymers and polymer blends

The growth in the application of electronic devices across a broad spectrum of military, industrial, commercial and consumer sectors has created a new form of pollution known as noise or radio frequency interference (RFI) or electromagnetic radiation or electromagnetic interference (EMI) that can cause interference or malfunctioning of equipment. Therefore, there is a greater need for the effective shielding of components from its adverse effects. This review surveys the shielding materials like metals, conducting plastics and conducting polymers for the control of electromagnetic radiations. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009

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EMI shielding: Methods and materials—A review

Thermal processing of starch-based polymers

The number of phases, transition temperatures, and microhardness of a series of poly(ester ether carbonate) (PEEC) multiblock terpolymers with poly(butylene terephthalate) (PBT) hard segments have been investigated as a function of ether/carbonate (EC) soft-segment composition at constant PBT content. The polymerization degree of PBT and the intrinsic viscosity of the terpolymers were determined by viscosimetry. The degree of crystal-Unity, long spacing, glass transitions Tg , and melting temperature were derived by means of x-ray diffraction, dynamic mechanical thermal analysis (DMTA), and differential scanning calorimetry (DSC) measurements. Surface mechanical properties were studied by microindentation tests. It was found that the terpolymer consists of two amorphous (EC and PBT) phases and one crystalline (PBT) phase. The Tg value of PBT does not depend on the chemical composition of the soft segments, in the contrast to the Tg of the soft-segment amorphous phase. Introduction of polycarbonat...

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Microhardness of Condensation Polymers and Copolymers. 2. Poly(Ester Ether Carbonate) Thermoplastic Terpolymers

Unit cell expansion data for branched polyethylene (PE) rapidly quenched from the melt are examined with reference to the level of chain defects incorporated within the crystal lattice. The data presented here complement earlier studies and show that the incorporation of defects, ɛc, after quenching is twice as large as the penetration obtained for slowly cooled samples. The parallel increase of the K-distortions parameter with ɛc is in direct support of the inclusion of a large fraction (40%) of bulky defects (butyl or larger) within the polyethylene lattice.

X-Ray diffraction study of lattice distortions in branched polyethylene rapidly quenched from the melt

https://digital.csic.es/bitstream/10261/228116/1/Ultra-microindentation.pdf

Ultra-microindentation at the surface of silk membranes

/pdf/microhardness-of-sintered-poly-4-hydroxybenzoate-and-poly-2-2gmrumnyf4.pdf

Microhardness of sintered poly (4-hydroxybenzoate) and poly(2-hydroxy-6-naphtoate) homopolymers: Influence of pressure and morphology

The continuous-time random-walk model used by Scher and Montroll to account for the dispersive transport phenomena observed in time-of-flight experiments on amorphous solids is extended to the non-isothermal case of thermally stimulated currents (TSCs). The basic implications of the theory of a TSC transport peak resulting from a system with random distribution of iso-energetic hopping sites are presented.

F. J. Baltá Calleja

Papers

Microhardness of Condensation Polymers and Copolymers. 2. Poly(Ester Ether Carbonate) Thermoplastic Terpolymers

X-Ray diffraction study of lattice distortions in branched polyethylene rapidly quenched from the melt

Ultra-microindentation at the surface of silk membranes

Microhardness of sintered poly (4-hydroxybenzoate) and poly(2-hydroxy-6-naphtoate) homopolymers: Influence of pressure and morphology

Thermally stimulated current transport peak in a system with spatially disordered hopping sites