Special Issue "Composite Materials"

Guest Editor
Prof. Dr. Ralf Riedel
Institut für Materialwissenschaft, Technische Universität Darmstadt, Petersenstr. 23, 64287 Darmstadt, Germany
Website: http://www.tu-darmstadt.de/fb/ms/fg/df/index.html
E-Mail:

Dear Colleagues,

Advanced composite materials are of particular interest in basic science as well as in applied research due to their high technological potential in the production of novel materials with tailor-made properties and with performance profiles far beyond those of the existing ones. The aim and scope of the research in this field is the development of materials with superior thermo mechanical, physical and chemical properties. The combination of different types of materials can lead to a great variety of composites, basically distinguished mainly by their constitution. Thus, the most prominent examples are denoted as polymer matrix composites (PMC), metal matrix composites (MMC) and ceramic matrix composites (CMC). In these cases, the composite comprises a matrix material in which one or more phases of another material are dispersed. The dispersed phase can be present in a variety of different morphologies such as fibers, whiskers, particles or platelets. Ideally, the resulting physical or chemical performance of the composite material is superior to that of the pure component phases. Depending on the size of the individual constituents, we distinguish between nano/nano-, nano/micro- and micro/micro-omposites.

In this special issue, novel trends related to synthesis and processing suitable for the production of advanced composites as well as the property profile of their derived novel materials are highlighted and discussed.

Prof. Dr. Ralf Riedel
Guest Editor

Related Special Issues in other Journals

Composite Materials in the International Journal of Moleular Sciences

Submission

All papers should be submitted to materials@mdpi.org. To be published continuously until the deadline and papers will be listed together at the special issue website.

Submitted papers should not have been published previously, nor be under consideration for publication elsewhere. All papers are refereed through a peer-review process. A guide for authors is available on the Instructions for Authors page. Materials is an international peer-reviewed quarterly journal published by Molecular Diversity Preservation International. Review manuscripts: Before writing their manuscripts, potential authors of review articles should forward the title and a short abstract to materials@mdpi.org. We will then provide feedback on the suitability of the topic.

Article Processing Charges (APC)

Article Processing Charges (APC) will be waived for well prepared manuscripts of invited papers. For the first two volumes of this new journal the APC are of 300 CHF (or 550 CHF per paper for those papers that require extensive additional formatting and/or English corrections).

• synthesis, processing, structural and functional properties
• theoretical studies (modeling and simulation)
• applications

Feature Papers

Type of Paper: Article
Title: Thermally Conductive, Tough Silicon Carbide Composite Attempting to Mimic Nature with High Strength up to 1600°C in Air
Authors: Toshihiro Ishikawa
Affiliations: Inorganic Specialty Products Research Laboratory, UBE INDUSTRIES LTD., 1978-5 Kogushi, Ube City, Yamaguchi Prefecture, 755-8633, Japan; E-mail: 24613u@ube-ind.co.jp
Abstract: We developed a unique approach toward improving the toughness of ceramics involving the creation of a textured internal structure within the ceramic itself, similar in some respects to the fibrous structure of wood. Actually, we developed a tough ceramic, which consists of a highly ordered, close-packed structure of very fine hexagonal columnar fibres with a thin interfacial carbon layer between fibres. The interior of the fibre element was composed of sintered beta-silicon carbide crystal. The toughness of the material in this case derives from the tremendous amount of interface area created within the internal structure through the close packing of the hexagonal columnar fibres. Furthermore, this ceramic also achieved the excellent high temperature properties, high thermal conductivity and low density. These properties will make it very attractive for replacement of heavy metal super alloy components.

Type of Paper: Review
Title: Silicone Resin — Silicone Oil Applications for Ceramic Precursors and Composites
Authors: Masaki Narisawa
Affiliations: Osaka Prefecture University, 1-1, Gakuen-Cho, Sakai 599-8531, Japan; E-mail: nar@mtr.osakafu-u.ac.jp
Abstract: This review will introduce history of silicone resins from opening remark of classic Rochow process, which guarantees low cost monomer synthesis directly from metallic silicon. Thermal degradation process of linear or cross-linked silicones will be reviewed from viewpoints of basic chemical reactions. Recent developments of Si-O-C ceramics derived from silicones will be introduced from viewpoints of tailored morphology, limitation of heat resistance and chemical compositions. Filler or cross-linking agent effects on polysilsesquioxanes will become main topic. Recent activity of our group about compatibility, ceramic yields and control of melt viscosity in polycarbosilane - silicone oil blend systems will be also included.

Regular Papers

Type of Paper: Review
Title: Microstructural Design and Properties of Infiltration Processed Alumina Matrix Composites with Graded Microstructures
Authors: I.M. Low, D. Asmi, P. Manurung and R.D. Skala
Affiliations: Centre for Materials Research, Department of Applied Physics, Curtin University of Technology, GPO Box U1987, Perth, WA, Australia 6845
Abstract: Infiltration processing as a novel route to simple fabrication of functionally-graded materials (FGMs) is described. An overview of the infiltration kinetics and the use of the infiltration process as a new philosophy for tailoring novel graded ceramic systems are presented. The processing involves initially the fabrication of a compacted porous preform, infiltration of the preform with an appropriate infiltrant, and finally the heat treatment to achieve densification. Various models of infiltration kinetics and their relation to FGMs are described. A good control of infiltration kinetics is essential for achieving quality graded phase composition and microstructure. The processing-microstructure-property relationships of various alumina-matrix FGMs such as alumina /mullite, alumina /aluminium-titanate, ZTA /mullite, ZTA /aluminium-titanate, and alumina /mullite /aluminium-titanate are discussed in relation to phase composition, microstructure, and mechanical properties. These materials display superior mechanical performance in terms of strength, fracture and thermal shock resistance. The potential of this novel processing approach to other graded architectures such as in-situ thin films and coatings supported on tough graded substrates is also discussed.

Type of Paper: Review
Title: The Present and Possible Future Use of FRP Composites in the Civil Infrastructure
Authors: L. C. Hollaway
Affiliations: Civil Engineering (C5), University of Surrey, GUILDFORD, Surrey, UK, GU2 7XH
Abstract: The paper will discuss the development of the advanced polymer composite material applications in the civil/structural infrastructure over the past three decades. It will endeavour to identify and prioritise research areas which are necessary to improve the understanding of the behaviour of FRP materials and FRP structural components. The paper will demonstrate the types of structures which have been developed from the material and the most advantageous way to employ composites in civil engineering. The material has extraordinary mechanical and important in-service properties which when combined with other materials are utilised to improve the stiffness/strength, durability and to lower the whole life cost and the environmental impact. The paper will conclude by summarising keys successes of the advanced polymer composite in the civil infrastructure.

Type of Paper: Review
Title: Wood/biopolymer/nanoclay Composites: A Review
Authors: Daniel De Kee * and Qingkai Meng
Affiliations: Tulane Institute for Macromolecular Engineering and Science (TIMES) and Department of Chemical and Biomolecular Engineering, Tulane University, New Orleans, LA 70118, United States; E-Mails: ddekee@tulane.edu; qmeng@tulane.edu; * Author to whom correspondence should be addressed
Abstract: Biopolymer/wood, biopolymer/nanoclay, and wood/biopolymer/nanoclay composites have recently been intensively studied. Biopolymers allow for promising substitutes for conventional petroleum-based polymeric materials as a result of their environmentally benign qualities. However, there are also problems associated with properties, such as brittleness, low melt viscosity, etc. Economic problems currently prevent wide-range applications. Here, we review the effects of wood fibers and nanoclay on biopolymers. In particular, we will address their effect on the flexural and tensile moduli, on the HDT, and on the temperature of thermal decomposition of the resulting nanocomposite materials.
Keywords: biopolymer; wood fiber; nanoclay; composite; poly (lactic acid)

Type of Paper: Article
Title: Investigations of Competitive Adsorption Processes in the Case of Glass Fibre Sizing
Authors: C. Bellmann, R. Plonka, N. Schäfer, A. Caspari and K. Grundke
Affiliations: Leibniz Institute of Polymer Research Dresden, Germany
Abstract: The mechanical behaviour of composite materials are determined by the properties of the reinforcing fibre, the polymer matrix and the interface between fibre and matrix. The matrix will be reinforced only in the case of high level of stress transfer between these two components. For increasing adhesion forces in the interface of glass fibre reinforced materials, coupling agents are used. But this agent is only one part of a sizing system which is responsible for good processing characteristics during manufacturing of the reinforcement, during transportation and handling of the glass product and during conversion to a composite part. Furthermore, the sizing must be optimised to give good performance characteristics in the final composite part. Normally, the glass fibre sizings are multi-component systems consisted of silane coupling agent (~10%), film former (~79%), lubricant (~4%), emulsifying surfactant (~4%), and anti-stats (~3%) in water and were applied to glass fibre prepared directly from molten glass. In case of E-glass fibre, ~5 wt% of the sizing mixture in water are applied. This composition is the result of a long time of experience in glass fibre industry. Much research has focused on the effects of silanol coupling agent on polymer/glass interactions. But, it is known nothing about action mechanisms of this multi-component mixture. Until now, nobody was looking to the influence of surfactants on the adsorption process and the effectiveness of the coupling agents. Investigations of adsorption processes of different components of textile finish show interesting effects by competitive adsorption processes of different parts of the finish mixture. Own research results in the field of ageing effects of sizings indicate similar effects for sizing mixtures. To study such adsorption effects, only two components of glass sizings will be regarded: the coupling agent and the lubricant.

Type of Paper: Review
Title: Electrochemical Deposition of Nanocomposites
Authors: Tao Wang
Affiliations: University of Wisconsin-Madison, Center for Nanotechnology, Madison, WI 53706, USA; E-Mail: twang8@wisc.edu; Tel. 01-608-262-7311
Abstract: Although electrochemical deposition has been used to produce metal matrix composites for decades, micro- and nanocomposites incorporating nano-sized second-phase ceramic, polymeric or metallic objects with tailored physical, chemical and mechanical properties have recently attracted much attention. This review will give a brief introduction to the fundamental principles with a focus on the object inclusion mechanisms, application-dependent processing of various material systems and property evaluation. It will cover electrodeposition, electroless deposition and electrophoretic approaches. The emphases will be placed on recent progress in carbon nanotube inclusion and emerging applications in tribology, corrosion, magnetic recording, MEMS, sensor and actuator, energy storage, photovoltaics, and biosensors.

Type of Paper: Article
Title: Cytotoxic Evaluation of Elastomeric Dental Impression Materials on a Permanent Mouse Cell Line and on a Primary Human Gingival Fibroblast Culture
Authors: F. Boraldi, C. Coppi, S. Bortolini, U. Consolo and R.Tiozzo *
Affiliations: Dept. Biomedical Sciences, Section of General Pathology, Dept. of Neurosciences, Section of Dentistry, University of Modena and Reggio Emilia, Modena, Italy
* Author to whom correspondence should be addressed; E-Mail: roberta.tiozzo@unimore.it
Abstract: The aim of this study was to determine and compare the cytotoxicity of different dental impression materials: vinyl polysiloxanes and polyethers. The cytotoxicity was evaluated on a permanent cell line, Balb/c 3T3, and on a primary cell line, human gingival fibroblasts, with direct and indirect tests. The degree of cytotoxicity was judged using the measurement of cellular proliferation and viability with MTT test. The polyethers were found to be more toxic than vinyl polysiloxanes. The primary cell line was less sensitive than the permanent cell line. Taking into consideration the limits of in vitro experiments, vinyl polysiloxanes might be the most recommendable products for intraoral and extraoral replicates.

Type of Paper: Article
Title: Biocompatibility of Different Collagen Membranes in Cultures of Human J111 Macrophages Cells
Authors: C. G. Aruta, M. A. Croce, D. Quaglino, D. Guerra and R.Tiozzo *
Affiliations: Dept. Biomedical Sciences, Section of General Pathology, University of Modena and Reggio Emilia, Modena, Italy
*Author to whom correspondence should be addressed; E-Mail: roberta.tiozzo@unimore.it
Abstract: We have carried out an in vitro study regarding the interaction of two different collagen membranes (types I and II) isolated from horse tendon, articular and trachea cartilage with human macrophages (J111), in order to obtain data on their biocompatibility. We have described the morphology of cells, seeded on collagen films, and we have evaluated their proliferation and the cytokines production. The inflammatory response may induce the destruction of collagen membranes and on the consequence modified their biocompatibility. The information, about these new collagen films, might be relevant for in vivo application such as “tissue engineering” and/or specialized cells implantation.

Type of Paper: Review
Title: Dielectric and Elastic Characterization of Nonlinear Heterogeneous Materials
Authors: Stefano Giordano
Affiliations: Dipartimento di Fisica, Università degli Studi di Cagliari, Complesso Universitario di Monserrato, S.P. Monserrato-Sestu Km 0,700, I-09042 Monserrato (CA), Italy
E-Mails: stefgiord14@libero.it; stefano.giordano@dsf.unica.it
Abstract: This review paper deals with the dielectric and elastic characterisation of composite materials constituted by dispersions of nonlinear inclusions embedded in a linear matrix. The dielectric theory deals with pseudo oriented particles shaped as ellipsoids of revolution: it means that we are dealing with mixtures of inclusions of arbitrary aspect ratio and arbitrary non-random orientational distributions. The analysis ranges from parallel spheroidal inclusions to completely random oriented inclusions. Each ellipsoidal inclusion is made of an isotropic dielectric material described by means of the so-called Kerr nonlinear relation. On the other hand, the nonlinear elastic characterization takes into consideration a dispersion of nonlinear (spherical or cylindrical) inhomogeneities. Both phases are considered isotropic (actually it means polycrystalline or amorphous solids). Under the simplifying hypotheses of small deformation for the material body and of small volume fraction of the embedded phase, we develop a theory for obtaining the linear and nonlinear elastic properties (bulk and shear moduli and Landau coefficients) of the overall material
Keywords: nonlinear constitutive equations; composites (nanosystems embedded in a larger structure); mixture theory and order parameters

Type of Paper: Article
Title: Mediterranean Coral Organic Matrix Influence on CaCO₃ Precipitation
Authors: Patrizia Vergni ¹, Eric Caroselli ², Simona Fermani ¹, Goffredo Stefano ^2,* and Giuseppe Falini ^1,*
Affiliations: ¹ Dipartimento di Chimica ‘G. Ciamician’, Alma Mater Studiorum, University of Bologna, Via Selmi 2, 40126 Bologna, Italy; ² Department of Evolutionary and Experimental Biology, Alma Mater Studiorum, University of Bologna, Via F. Selmi 3,40126 Bologna, Italy
* Author to whom correspondence should be addressed; E-Mail: giuseppe.falini@unibo.it
Abstract: Scleractinian corals from Mediterranean are made mainly of aragonite. In them the deposition of calcium carbonate occurs in a biological confined environment. However, it is still a theme of discussion at which level the calcification occurs under biological and environmental control. The skeleton of coral contains an intracrystalline organic matrix that has been so far characterized in some of its chemical and physical properties. In this work the organic matrix from the skeleton of the Balanophyllia europaea, a solitary scleractinian coral living in the Mediterranean sea, is studied with the aim of understanding its role in in vitro crystallization of calcium carbonate. The crystallisation of calcium carbonate has been carried out by diffusion of ammonium carbonate vapour in solution of calcium chloride containing different amounts of the soluble organic matrix, both soluble and insoluble components, and magnesium ions. The results have shown that the organic matrix components influence the calcium carbonate precipitation and that this effect is enhanced by their co-presence. Also the effect of magnesium ions on the precipitation of calcium carbonate is regulated by the presence of the organic matrix components. The organic matrix influence on calcium carbonate crystal morphology, aggregation and polymorphism is discussed as a function of the content of magnesium ions in the precipitation environment.

Type of Paper: Review
Title: Thermal Decomposition of Composites by Fire
Authors: Javier Trelles
Affiliations: Hughes Associates, Inc., USA; E-Mail: jtrelles@haifire.com
Abstract: Modern fiber-reinforced materials such as sandwich composites exhibit favorable characteristics in the areas of strength-to-weight ratio and corrosion resistance. Failure under the action of mechanical stresses is typically plastic but many modern constructions can still maintain a measure of structural integrity thanks to the type and arrangement of the fibers. Damage by the action of unwanted fires, however, poses a more formidable challenge to strength characteristics. Although many composites are formally flammable, fire resistant formulations have been very successful in controlling and limiting flame spread along exposed surfaces. Nonetheless, prolonged exposure to fire temperatures and heat fluxes will cause the material to decompose. Using the sandwich composite as a concrete example, the cured resign holding the fibers together will be the first part of the construction to be affected. It will respond by melting, chemically decomposing, and eventually gasifying. As the resin wastes away, bare fibers delaminate. The progress of the thermal wave next has an impact on the wood. Composite materials, like wood itself, decompose in stages. The first stage for the wood is gasification and chemical pyrolysis of its resins accompanied by dehydration. The outcome is a high-carbon-content char very similar to char coal. This in turn decomposes in its own stage. The end results for the wood is a mostly inorganic ash. Unlike solid explosives, combustion does not typically occur inside the structural composite because the gases in the pores are too fuel rich. Combustion instead occurs outside of the material. The fuel comes from the gasified decompositions and the oxidizer from the ambient air. The heat fluxes from the resulting flame work in conjunction to sustain the thermal decomposition. Depending on the resulting fire environment and the original properties of the material, the composite can be severely compromised structurally. The goal of this article is to review the theory of thermal decomposition of composite materials and to detail the work done to date address the survivability of composites in the presence of fires.

Type of Paper: Review
Title: Pseudo-Scaled and Scaled Description and Scaleportation of Inorganic and Organic Polymer and Polymer Composites Properties
Authors: V. S. Travkin and N. N. Bolotina
Affiliations: Hierarchical Scaled Physics and Technologies (HSPT), Los Angeles, CA, USA
Abstract: We start with a short outline in which some definitions of a few scales physics and a developed volume of results that is used in the contemporary physics will be introduced. We continue with the reminding of the history of structure-properties relation-formulation in 80s-90s including the calm fading of that campaign, and then we go on with the currently proposed approaches. The specific attributes of complex materials, biomedia and tissue engineering are hardly to be achieved without polymer-based constituents. That is of interest in promoting the understanding of multiscale studies. We consider the new techniques of "multiscaling" that allegedly connect different scale properties of polymers and polymer-based composites, materials. The critical review will be dealing mostly with the attempts to "multiscale", pseudo-scale, quasi-scale, ad-hoc scaling approaches and techniques in physics, mostly in continuum mechanics and materials science and related to polymer and polymer-based materials and composite modeling fields. The claims of this kind would be better to name as multi-resolution ones. At the same time, we compare and describe in some detail the true multiscaling mechanisms stemmed from the heterogeneous analogs of Gauss-Ostrogradsky theorem (GOT) and further use of those theorems (WSAM) for the same purposes which used the homogeneous GOT. The interests will be focused on the problems of scaled materials, composites with multiscale, heterogeneous, nonlocal and nonlinear character.

Type of Paper: Review
Title: Impact Behaviour of Glass Filled Fibre-Reinforced Thermoplastic Engine Components
Authors: Z. Mouti ¹, Keith Westwood ², K. Kayvantash ¹ and J. Njuguna ^1,*
Affiliations: ¹ Centre for Automotive Technology, Department of Sustainable Systems, Cranfield University, Bedfordshire, UK
² Eaton, Automotive Group, West Midlands, UK
* Author to whom correspondence should be addressed; E-mail: j.njuguna@cranfield.ac.uk
Abstract: Weight reduction is vital in the automotive industry in order to help reduce fuel consumption and emission levels to meet present and future standards. Among the new technologies used widely to meet the challenge of cost and performance, thermoplastic materials have long been held in high regard. The usage of polyamides as a composite in under-bonnet parts has grown considerably these last years thanks to its well-balanced performance profile that have allowed the replacement of metals, thermoset and other materials. In particular, polyamide glass fibre-reinforced plastics offer distinct advantages over more conventional engineering materials such as aluminium and steel including higher specific strengths and stiffness’s, superior corrosion resistance as well as improved fatigue properties and the cost of manufacturing components is often less than with more conventional metals. However, it has some limitations and the most significant is their response to localised impact loading such as that imparted by a dropped tool or road debris. The intention of this paper is to critically review impact resistance of currently used thermoplastic material by focusing on the engine and transmission oil pans which are most exposed to high rate impact. An attempt is made to draw much of the work published in the literature and also our own work so as to identify the fundamental parameters determining the impact resistance of a glass-filled polyamide oil pan module. This is intended to bring about a detailed understanding of the mechanisms of component failure and also shed some light in damage tolerance of typical under-the-hood automotive components.
Keywords: oil pan; sump; impact resistance; polyamide; glass fibre-reinforced composite

Type of Paper: Review
Title: The Strengthening of Mg and Mg Alloys by Short Fibres and Particles
Authors: Erhardt Lach
Affiliations: French-German Research Institute of Saint-Louis, ISL 5, rue du Général Cassagnou F-68301 SAINT LOUIS, France; E-mail: erhardt.lach@isl.eu
Abstract: Mg and its alloys are the metallic materials with the lowest density in industrial scaled use. For many applications the strength of Mg alloys is not sufficient. For that reason in the last three decades many research has been done to reinforce Mg alloys by incorporating short fibres and particles. In this way the compression strength is significantly increased whereby the strain to failure is strongly reduced, but there is only a minor effect of the reinforcement on the tensile strength. MMC’s are mainly elaborated by infiltration of a preform or a mould, which is charged by particles. The processes are mainly the squeeze casting or the gas pressure infiltration. The mechanical properties are also influenced by the shape of the reinforcement. The Orowan mechanism is governing the strengthening of particle reinforced MMC’s. Whereby short fibres influencing the mechanical property by their tensile strength. Therefore the bonding between the incorporate fibres and the matrix alloy is important. Particles are strongly increasing the Young’s modulus also.

Type of Paper: Article
Title: Some Properties of Strand Board Panels Manufactured from Eastern Redcedar
Authors: Salim Hiziroglu
Affiliations: Department of Natural Resource, Ecology&Management, 303-G Agricultural Hall, Oklahoma State University, Stillwater, OK 74078-6013, USA; E-mail: salim.hiziroglu@okstate.edu; Tel. 405-744-5445; Fax: 405-744-3530
Abstract: This study evaluated some of the properties of experimental strand board panels with random flake alignment manufactured from low quality eastern redcedar (Juniperus virginiana L.) logs. Panels were made at two density levels of 0.65 g/cm3 and 0.78 g/cm3 using phenol formaldehyde adhesive at 8% rate. Mechanical properties including modulus of elasticity and modulus of rupture and internal bond strength of the panels in addition to their thickness swelling characteristics were evaluated. As expected mechanical properties of the samples improved with increasing panels density. Thickness swelling for 2-hr and 24-hr water soaking ranged from 6.32 % to 18.41%. Both physical and mechanical properties of the panels showed acceptable and comparable results to those found in past studies used other species to manufacture similar type of product. Based on initial findings of this study it appears that eastern redcedar which is an under-utilized invasive resource can have a pot ential to be used as raw material for structural panel manufacture.
Keywords: strandboard; eastern redcedar; mechanical properties

Type of Paper: Review
Title: Tuneable Composite Metamaterials with Arrays of Magnetic Microwires
Authors: L.V. Panina, M. Ipatov, V. Zhukova, G. Aranda and A. Zhukov
Affiliation: Dept. Material Physics, Chemistry Faculty, P.O. Box 1072, 20080 San Sebastián, Spain
Abstract: Composite structural materials containing periodic or random arrays of metallic wires often referred to as wire metamaterials have a strong dispersion of the dielectric function in the GHz frequency band. This behaviour could be of plasmonic or resonance type for long or short-cut wires, respectively. In both cases, the real part of the permittivity can be negative in the dispersion region resulting in many fascinating effects including negative refraction and frequency selective band-gap or band-pass regimes. A recent trend is to achieve adjustability in these structures. Here we review recent results on tuneable metamaterials utilising thin ferromagnetic wires exhibiting magnetoimpedance effect (MI). Our and some other groups work demonstrates that this leads to powerful adjustment of their electromagnetic properties, in particular, effective permittivity, by a weak magnetic field or a mechanical stress. Thus, enhanced transmission (by more than 10 dB) in a narrow frequency region near 2 GHz through a silicon layer containing Co-rich amorphous wires of 5 cm long in the presence of a magnetic field has been reported. Furthermore, new effects as microwave activity typical of chiral structures can be foreseen. This paper also discusses potential applications of magnetic wire metamaterials in reconfigurable networks, tuneable 'microwave windows', structural health monitoring, and remote stress/temperature sensing.

Type of Paper: Review
Title: Tailoring Anisotropic Optical Properties of Glass-Metal Nanocomposites with Ultrashort Laser Pulses
Authors: Gerhard Seifert* and Heinrich Graener
Affiliation: Physics Department, Martin-Luther-University Halle-Wittenberg, D-06099 Halle, Germany; * Author to whom correspondence should be addressed; E-mail: gerhard.seifert@physik.uni-halle.de
Abstract: Glasses containing metallic nanoparticles show very promising linear and nonlinear optical properties, mainly due to the surface plasmon resonance (SPR) of the nanoparticles. Spectral position (in the visible and near-infrared range) and polarization dependence of the SPR are, besides other parameters, characteristically determined by the nanoparticles’ shapes. The focus of this review will be on nanostructural modifications in glass-metal nanocomposites induced by femtosecond laser pulses. In particular, a comprehensive physical picture of the processes leading to laser-induced persistent shape transformation of the nanoparticles will be given. In addition, the resulting local optical dichroism allows producing very flexibly polarizing optical microstructures. The achieved considerable progress towards technological application of this technique will also be discussed.

Type of Paper: Review
Title: Interface Reactions and Reaction Synthesis of Composite Systems
Authors: J. S. Park and J. M. Kim
Affiliation: Division of Advanced Engineering Materials, Hanbat National University, Daejeon, 305-719 Korea
Abstract: Interface reactions in composite systems often determine overall properties of composite systems, since product phases usually formed at interfaces during composite fabrication processing makes a large portion of the composites. Since most composite materials represent a ternary or higher order materials system, many studies have focused on analyses of diffusion phenomena and kinetics in multicomponent systems. However, the understanding of the kinetic behavior increases a complexity, since the kinetics of each component during interdiffusion reactions need to be defined for interpreting composite behaviors. In this standpoint, it is important to clarify the interface reactions for producing compatible interfaces with desired product phases. A thermodynamic evaluation such as a chemical potential of involving components can provide an insight to understand the diffusion reactions, which resulting to governing diffusion pathway and product phase formation. A strategic approach for designing compatible interfaces is discussed in terms of chemical potential diagrams and interface morphology with some materials examples.

Type of Paper: Review
Title: Types of Tooth-Colored Composite Dental Biomaterials; Competition and Combination
Author: E. C. Combe
Affiliation: University of Minnesota, Minneapolis, MN 55455-0459, Minnesota, USA
Abstract: Two major quests have been prominent in dental Biomaterials research for the last half-century: (1) The need for tooth-colored restorative materials, (2) The development of materials capable of adhesion to teeth.
There are two major distinct systems: (1) Polymerizing materials, based on dimethacrylate monomers with inorganic fillers. Adhesion to tooth enamel is by a micromechanical bonding, and to dentin by hybridization. (2) Aqueous solutions of polalkenoic acids which react with a fluoro-aluminosilicate glass, adhering to tooth substance by an ionic mechanism.
These two material types have been suggested for the restoration of teeth, pit and fissure sealants, orthodontic bonding and dental adhesives.
These material types are in ‘competition’ with each other, and also new materials have been developed which are combinations of the two types. These hybrid materials include resin-modified glass-ionomers and compomers. These materials are compared and contrasted in terms of their structure, properties and applications.