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I.13   Science and New Materials


Physics and chemistry of new materials: from basic research to technological development. Prospects for advanced materials to meet specific needs. Superconductors. Optoelectronics. Smart materials. Nanostructured materials.

Chair: Richard A. Catlow The Royal Institution, UK
Rapporteur: John Corish Trinity College, University of Dublin, Ireland

Session co-ordinator: John Corish Trinity College, University of Dublin, Ireland
Local secretary: J. Gyulai Research Institute for Material Sciences, Hungary

Challenges for polymer sciences in the 21st Century

Alexei Khokhlov
Department of Physics, Lomonosov State University, Russia

Polymer science was one of the most rapidly developing fields in natural sciences in the second half of the 20th century. This was due to unique position of this field at the boundary of physical and organic chemistry, condensed matter physics, molecular biology and different branches of materials science. As a result, all most important developments in this field influenced essentially polymer science as well. For example, the discovery of the structure of double helix of DNA in 1953 stimulated the development of a large field of biopolymers research which is now constituting one of the most important research directions of polymer science.

This diversity in the disciplines having relation to polymer science is also manifested in the diverse character of applications of this field. These applications range from the use of polymers as construction materials (plastics, rubbers, fibers) and for functional purposes (paints, superabsorbents, membranes, optically active media, all kinds of "smart" materials) to the explanation of the molecular origin of processes in living cells.

The success for the research of a polymer scientist in the 21st century will depend on his ability to accumulate knowledge from all the above-mentioned different disciplines, and to use this knowledge in a wide range of application fields. This originates special requirements for the optimum educational programs for polymer science. This problem will be discussed in the talk in detail.

As to the place of polymer science on the "map of sciences" of 21st century, its important and key position will be ensured by its numerous applications (mainly of molecular biological and molecular electronics nature) and by its role in connecting different disciplines. Examples of combining of methods and approaches of different fields of science within the area of polymer research will be discussed.

The importance of interfaces

Roger Horn

Ian Wark Research Institute, University of South Australia, Australia

The interfaces between different material components play an important role in the performance of many modern materials, and there is every reason to expect that their importance will continue to grow in the future. For these reasons it is argued that the scientific understanding of interfaces is a key to the continuing development of new materials.

Why are interfaces important? Broadly, three reasons can be identified:

Where a material consists of more than one component, the manner in which those components are joined together is vital to the properties of the material. An example is in composite materials such as fibre-reinforced polymers (FRP). Such composites benefit from the high strength of the fibre component but have much greater toughness (resistance to fracture) that the fibre material would have on its own. In fact, the toughness of FRPs is tens or hundreds of times higher than that of the either of the component materials, because it results very largely form the properties of the interface between them.

Where a material has a granular structure, the interfaces between grains play a similarly important role. An example is in ceramic materials which typically consist of small grains of metal oxide, nitride or carbide crystals. Ceramic materials have excellent strength, strength per unit mass and corrosion resistance, but they suffer from being too brittle for use in many applications. The mechanical properties of most ceramics is determined primarily by the properties of the intergranular interfaces.

The functionality of some materials relies on the particular properties of interfaces. For example, the action of microelectronic devices is based on the current-rectifying effect of interfaces between oppositely-doped semiconductor materials.

Why will interfaces be of increasing importance in the future? First, as scientists and engineers explore more materials for potential use, there will be continued development of composite materials, for the simple reason that there is a far greater range of composite materials to be investigated and developed than there is of monolithic (single-component) materials. Furthermore, there will be increasing development of more complex composites involving more than two components, and hence more types of interface, so the issues of interfacial properties between these components will always be important. Second, with ever-increasing miniaturisation of components, for example in microelectronics and in the burgeoning area of nanotechnology, the importance of interfaces increases. This is because, as the component size decreases, a greater proportion of the material is found in or near an interfacial region. By the time one reaches nanostructured materials, the interfaces become predominant.

Small Scale Materials Science with Large Scale Facilities

Bruce D. Gaulin
Department of Physics and Astronomy, McMaster University, Canada

Comprehensive studies of the properties of new materials routinely involve the use of large-scale materials science facilities, such as synchrotron x-ray and neutron sources, as well as muon spin rotation laboratories. These large facilities function in a manner intermediate between those which are normally thought of as "big science" facilities, and small scale research facilities typical of university-based materials research laboratories.

These sources are expensive, and therefore few exist, and are operated as either national or international facilities. However the User community associated with many such large laboratories ranges from about one hundred to a thousand. Because they accommodate so many users, researchers have relatively little time available at the facility, and making progress requires that the experiments fit into a hierarchy of studies, in which the new materials have already been well characterized by traditional small scale materials science techniques, such as heat capacity, resistively, and susceptibility, before the experiment at the large scale facility is attempted.

The materials research community which is expert in these neutrons, synchrotron, and muon techniques is relatively small. The large majority of users of these facilities will require expert collaborators from the facility or elsewhere. Efficient use of these laboratories requires collaborative programs that ensure that these facilities are part of a coherent program, which mesh materials preparation and characterization into the use of large-scale facilities.

Porous Solids, Environment and Strategic Developments

Gérard Ferey
Institut Lavoisier, Université de Versailles, France

The most known porous solids are natural and synthetic zeolites which are aluminosilicates. At the atomic scale, their crystal structures show empty tunnels or cages, with dimensions in the range of 8-10Ĺ. These pores can accept guest molecules and this property was widely used in the domains of petrochemistry, catalysis, ion exchange and gas separation. These properties created an increasing demand from the concerned industries which asked for ‘tailor-made compounds’ for more and more specific applications. Therefore, there has been an enormous growth in the chemical diversity of open framework inorganic materials during the 1990s. Most of them are based upon oxygen-containing materials, especially phosphates, but there is a growing list of examples based upon other chemistries (oxide fluorides, nitrides, sulphides...).

At the beginning of the XXIth century, and owing to the environmental problems which take every day an increasing importance, porous solids, owing to their capabilities of absorption linked to the existence of the pores, can provide more than before a solution to many problems: elimination of toxic species, storage of radioactive species... This needs a real design of particular solids for given applications, and therefore, a deeper understanding of the formation of these solids to manage the synthesis of solids with dimensions and shape of pores adapted to a particular purpose.

The lecture will show on several examples the state of the art in the domain, with the examination of the results, an analysis of the mechanisms and, after a critical analysis of the present results, strategic developments which have just been discovered and which open the way to solutions to some environmental problems.

New materials: their contribution to our futures

John Corish
Trinity College, University of Dublin, Ireland

Progress in the modern physical, chemical, biological and engineering sciences has made it possible to design, synthesise, and to characterise substances on the molecular level, to assemble them into novel structures and to find applications for such new materials. The impact of these advances will in the future encompass most sectors of industry and optimum participation will require investment in research across a wide range of materials from polymers to ceramics and beyond. A multidisciplinary approach to this development is essential if materials chemistry is to serve as the key enabler in new technologies such as electronic components and systems, bio-materials and healthcare, nanotechnology, energy generation and storage and in the communication media.

This presentation will review some of the areas in which new materials are likely to make major impacts and will describe the particular advances that are required in each. The diversity of opportunity for innovation is essentially unlimited in the design of active constituents and in their modification by the applications of coatings or through minor additions of dopants. The extension of properties, on the one hand to withstand extremes of temperature and pressure and on the other to render materials biocompatible is another challenge facing the material scientist. As we come ever more closely to grips with our atomic world, and increase our ability to assemble the exact molecules and larger structures that we require we will be empowered to provide solutions for ever more complex, interesting and important problems.

Part of this presentation is, with permission, based on a 'Scientific Forward Look for Chemistry' a paper compiled for the Royal Society of Chemistry by Dr. Mario Moustras as part of its foresight programme. Further details of that programme can be found on the RSC Website

Computer modelling of materials at the atomic scale

Richard Catlow
The Royal Institution, UK

One of the key advances over the last twenty years in general scientific methodology has concerned the ability to construct increasingly accurate models of molecules and materials at the atomic level. In the talk, we highlight recent applications of this exciting field in the science of materials. In particular, we will describe how atomistic modelling techniques are used to reveal the complexity and beauty of the structures of complex crystals and glasses. We will then explore surfaces and surface processes including molecular adsorption and reaction, of major importance in the industrially important field of heterogeneous catalysis. Next we will show how modelling methods allow us to investigate the movement of atoms in materials. We will conclude by discussing how the continuing spectacular growth in computer power is likely to influence future developments in the field.


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