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INTELLIGENT MATERIALS SYSTEMS

AND MATERIALS SCIENCE RESEARCH
IN AUSTRALIA

The concept of "smart/intelligent" materials systems is receiving increasing attention by researchers worldwide. This article summarizes recent developments reported at the Army Research Office Far East cosponsored AsiaPacific Workshop on Intelligent Materials Systems and Structures, held at the University of Wollongong in August 1991, and reviews some of the research activities in materials science at various universities and government and industrial laboratories in Sydney and Melbourne.

by Iqbal Ahmad

REVIEW OF THE WORKSHOP review, was held at the University of

Introduction

Since the first Army Research Office (ARO) supported workshop on Smart Materials, Structures, and Mathematical Issues, held at VPI in 1988, there have been a number of workshops and symposia on the subject in various countries. For example, an international workshop was held in Japan in 1989, which was followed by a U.S.-Japan workshop on Smart/Intelligent Materials and Structures held in Hawaii in March 1990 [see the article by I. Ahmad, "U.S.-Japan Workshop on Smart/ Intelligent Materials and Systems," Scientific Information Bulletin 15(4), 67-75 (1990)]. The Proceedings of the latter were published by Technomic Press in 1991. In fact, there is now a worldwide interest in the concept of "smart" or "intelligent" materials and structures. In nearly every country with advanced research activities in materials science and engineering, it is being discussed in various national and international forums. The most recent workshop, which is the subject of this

Wollongong, Australia, from 19-21 August 1991.

chemical systems based on unique groups of polymers that are inherently dynamic. The focus of their current research is on active membranes. Assuming them to be intelligent material systems, he identified the characteristics of an intelligent system to include sensing, transduction, and response. The motivation of developing the intelligent materials systems concept included not only the possibilities of discovering new materials but also new production processes and new material characterization techniques.

The main objective of this workshop was to explore the potential of this emerging technology in the context of the research, development, and testing (RD&T) capabilities of Australia. It was cosponsored by ARO Australia. It was cosponsored by ARO Far East (AROFE) and a number of Australian organizations including the New Materials and Technology Committee, Monsanto, BHP, the Royal Australian Chemical Institute, Illawara Technology Corporation, and the University of Wollongong. There were The Concept about 40 participants, all from Australia except for 3 from Japan and 2 from the United States.

The deputy vice chancellor of the university, Professor G. Sutton, gave the welcome address. Then Professor Gordon Wallace, who was the chairman of the workshop and is the director of the University of Wollongong's Intelligent Polymer Research Laboratory, described the activities of his laboratory in the area of intelligent polymers. He stated that their interest was

Professor Craig Rogers of the Virginia Polytechnical Institute, in his keynote speech, stated that man had always used nature as a source of inspiration for design and engineering of the materials and structures needed by society. The development of the concept of intelligent materials and systems was essentially mimicking nature to produce lifelike functions of sensing, actuation, and control. Realizing that there was as yet no consensus of the

in the development of intelligent scientific community on the definitions

of the terms "smart" and "intelligent," he gave his own version. He preferred to use the term "smart" for the materials and engineering systems and “intelligent" for the science aspect of the concept. He stated that in his opinion no monolith material was intrinsically intelligent. All intelligent materials in nature were systems, such as composites. He gave a number of examples of the smart/intelligent systems and structures that are being developed in the United States, as well as some of those that occur in nature. These systems are designed to adapt to the environment and represent the integration of the software with sensing and actuation.

Professor K. Takahashi of the Tokyo Institute of Technology spoke on the concept of intelligent materials and electronics. He reiterated what he had said in the previous two workshops about the definition of intelligent materials and stated that "intelligent materials" might be reasonably referred to as materials that possess characteristics similar to or exceeding those found in biomaterials.

Professor M. Aizawa of the Department of Bioengineering, Tokyo Institute of Technology, described an intelligent bimolecular material that incorporates three functional moieties, such as sensing, processing, and actuating functions, in a single molecule or that integrates these functional molecules in a collaborative supramolecular assembly. Since such molecules respond to specific information, resulting in an action of the actuating moiety, they have found a variety of applications in drug delivery systems. He used the example of calmodulin, which has covalently been conjugated with phosphodiesterase (PDE) as a model case of an intelligent bimolecular material. Calmodulin specifically binds the calcium ion, which changes its conformation, triggering PDE in its enzyme activity. The enzyme activity is modulated by calcium ions in solution through a

conformational change, which indicates that the information was transmitted from the calmodulin to the PDE moieties. This example is one of the closest (in my opinion) to the realistic characteristics of a smart/intelligent supramolecule and shows that such molecules can manifest intrinsic characteristics of the smart/intelligent concept.

Some Intelligent
Materials Systems

There were a number of papers from Australian institutions that identified various intelligent functions in biosystems. For example, Dr. Bruce A.M. Cornell of the Division of Food Processing, Commonwealth Scientific and Industrial Research Organization (CSIRO), North Rye, New South Wales, described a number of molecular systems that can be used in data storage, switching, sensing, and diagnostic devices. Molecular properties of biological membranes are his main research focus, and he discussed some of the focus, and he discussed some of the conduction properties and applications conduction properties and applications of synthetic lipid bilayers and the membrane-associated ion channels.

Dr. M. Crossley of the Department of Organic Chemistry, University of Sydney, discussed molecular electronics, which involves a “molecular wire" enabling electron flow between functional components of the system. According to Crossley, porphyrin systems in which individual porphyrin rings are directly fused or bridged by coplanar aromatic systems should meet these criteria. He is also studying a series of tetra-azanthracene-linked porphyrins, which manifest many properties that may be applicable to the synthesis of molecular electronic devices.

Dr. G. Bell of the Sensory Research Center, CSIRO, reported his work on chemical sensors based on the combination of olfactory receptor molecules and conductive electroactive polymers for process control and safety.

Professor H. Green of the Department of Physics and Mathematical Physics, University of Adelaide, gave an interesting overview of the structure and function of some of the important components of the nervous system and the cortex of animals. He described some simplified models of realistic neural networks capable of parallel processing and highlighted the role of mathematical modeling in these activities.

New Applications of the Concept

On the more applied side, Professor Y. Osada of Ibaraki University, Mito, Japan, reported on the first model of an electrically driven artificial muscle possessing motility like that of a robobug. The system is based on a chemomechanical process driven by the electrokinetic molecular assembly reaction in a weakly cross-linked polymer gel of poly(2-acrylamido-2-methyl propane sulfonic acid (PAMPS). When 20-V dc voltage is applied through a pair of carbon electrodes (450 mm long by 10 mm wide separated by a distance of 20 mm) placed on the upper and bottom sides of the hydrogel, and altering the polarity with 1-second intervals, the gel walks forward by repeating the bending and stretching action. The velocity of walking of the looper is a function of the applied current and salt concentration of sodium sulphate and the molecular size of the alkyl chain of the surfactant used. The actuation mechanism involved is different from piezoelectric materials or shape memory alloys as it is based on water-swollen hydrogel and makes continuous or analogue type movement.

The theory of electric field driven switches was the topic of the presentation by Professor N. Hush of the University of Sydney, in which the possibility of employing weakly coupled symmetrical bistable molecules or ions that undergo configurational change under external perturbation in hypothetical

logic or memory circuits was discussed. Factors influencing memory time and switching rate for dynamic and static RAM operations were described in connection with the theoretical possibility of constructing logic gates with suitable molecular switch circuits.

Professor Unsworth, director of the Center of Materials Technology and the head of Department of Materials Science, described electronic devices and circuits fabricated in his laboratory from electroactive polymers, particularly those designed to protect sensitive financial information stored on microprocessors against "hardware hacking." Unsworth suggested these devices can be of value to protect software used in command, control, com

in FY1992 (the managing agency is in
parentheses).

• Foundation of Intelligent Systems
(ARO)

• Interdisciplinary Research in Smart
Materials, Structures, and Mathe-
matics (ARO)

• Materials for Adaptive Structural
Acoustic Control [Office of Naval
Research (ONR)]

• Tactile Information Processing:
Biological and Machine Object
Recognition and Manipulation
(ONR)

Force Office of Scientific Research (AFOSR).

With respect to the most important areas in which research should be directed, in the context of the Australian scene, the consensus of the participants indicated biosensors, membranes, use of electroactive polymers for data storage and integrated circuits, controlled drug release systems, prosthetics, and molecular electronics and devices.

Considerable interest was expressed by some of the Australian participants in the ARO-supported URI program. I provided as much information as was available and then suggested that they contact the ARO program managers in the field.

munications, and intelligence (C31) Conclusions of the Workshop RESEARCH PROGRAMS IN operations.

U.S. Government
Funded Projects

Professor Rogers, in his second presentation, reported on some of the projects in the area of smart structures funded by the National Aeronautics and Space Administration (NASA), the Department of Energy (DOE), the National Science Foundation (NSF), and some Department of Defense (DOD) agencies. One of the important points he made was that most of the researchers involved in developing smart structures in which piezoelectric materials, electrorheological fluids, or shape memory alloys are being used did not appreciate the magnitude of the force required by the actuating assembly to perform the job in real applications such as vibration control. He emphasized the need for new actuator materials with increased "authority."

I summarized the ongoing program on Smart Materials and Structures managed by ARO and also briefly described the scope of the following programs under the University Research Initiative (URI) that will be initiated

In the panel discussion at the end of

MATERIALS SCIENCE

the presentations, comments were made General Comments
by the Australian Government and
university representatives and the
Japanese and U.S. participants pointing
out that the topic of intelligent materials
systems is of great future significance
to materials science and industry. The
United States and Japan have been
quick to recognize this potential, but
Australian involvement in this area is
relatively new. Several questions
questions
such as establishing multidisciplinary
research teams with a "critical mass"
and how to fund research in this new
area were raised. One of the govern-
ment representatives indicated that there
would be no new funds available from
the government agencies. I suggested
that some windows of opportunity, such
as the Window on Science program of
the Office of Naval Research Asian
Office (ONRASIA) and the Exchange
Visit program of ARO, which could
lead to some collaborative research with
U.S. scientists, were available. This
was enthusiastically received and a
number of questions were asked about
number of questions were asked about
the scope of activities of the international
offices of ARO, ONR, and the Air

Australia is a large country (about the size of the United States) with a population of only about 17 million. It is rich in natural resources including minerals and energy. Traditionally, its economy has been based on the export of primary products including minerals, grains, wool, and other dairy products. It has a relatively small manufacturing sector, serving mainly its small population. Australia has a relatively high standard of living. To maintain it, it is essential to vitalize its manufacturing sector, for which the importance of R&D is well recognized. Considering the number of people in the country, the R&D base in science and technology is good. However, R&D is mainly funded by the Federal Government and to a much lesser extent by the State Governments, rather than by industry. At the same time the utilization of the results of these research activities by industry is very low, which is discouraging the research institutions. Nevertheless, it is slowly changing, under the new government policies to vigorously

promote R&D in areas important for the economy of the country. One of the major fields of science seen to be the key to Australia's industrial future is materials, of which advanced ceramics forms a prime sector. Consequently, most of the laboratories I visited are involved in R&D in ceramics and thin ceramic films.

processing of materials for materials fabrication and manufacture are amongst the priority areas supported amongst the priority areas supported by these grants. Grants for industry R&D (GIRD) and new materials technology (NMT) are awarded annually to consortia consisting of both research institutions and industry in high tech materials science including surface engineering, optoelectronic materials and devices, high T superconductors, engineering polymers, biomaterials and devices, engineering ceramics and advanced structural and composite materials, and advanced processing of materials. Finally, a new government initiative announced in 1990 is the Cooperative Research Centers (CRC) program, which will fund up to 50 centers, with total government funding rising to $A100 million per annum by 1995. In addition, there are programs supported by the State Governments. Therefore, on the whole, there is no weakness in government policies of R&D promotion, particularly in materials science, which brightens the future of materials science and technology in Australia. However, at this time, one can find some very active groups conducting world class research, but there are a number of institutions where the level of research is only fair or weak.

In 1989-90 the Australian Government support for major programs in science amounted to $A2.4 billion, of which government research agencies received $A813 million. Most of the high tech ceramic research was in CSIRO, the Defense Science and Technology Organization (DSTO), and the Australian Nuclear Science and Technology Organization (ANSTO). To encourage industrial participation in research, an R&D tax concession is the major instrument used by the Government. The Australian Research Council (ARC) is a major arm of the government science policy that recommends funding to the universities. In 1990 the ARC allocated grants totalling $A66 million of which $A32 million went to five universities. One of the priority areas for these grants is materials science and mineral processing. The Offset Program established by the Government provides opportunities to obtain new technology and access to international markets. Where govern- Site Visits ment purchase contracts made with overseas suppliers contain in excess of $A2.5 million worth of imported content, the overseas supplier is required to perform "offset activities" in Australia to a value of 30% of the value of the contract's imported content. These activities may include R&D and technology transfer. Special grants to enable Australian scientists to participate in international scientific research are administered by the International Science and Technology Advisory Committee (ISTAC), for which an allocation of $A2.35 million has been announced recently. Optoelectronic materials and technologies and advanced

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At the University of New South Wales, Professor Dou is developing advanced techniques to fabricate and characterize high T wires, which have shown one of the highest J values. The work is being supported by an industrial consortium. An impressive facility for the deposition of diamond films and characterization of thin films of diamond and cubic boron nitride is headed by Professor McKenzie. He has established a modified arc-evaporation system to deposit thin, dense, and porefree films of diamond and other inorganic phases. The conventional arcevaporation techniques used extensively

to apply wear-resistant coatings to machine tools has the problem of extensive distribution of microparticles, which limit the performance of the coatings. McKenzie filters out these particles using a magnetic plasma duct. The ions produced in the arc-evaporator are focussed into the plasma duct, which consists of a vacuum tube surrounded with magnetic solenoids. The electrons in the plasma are confined by the magnetic field. The resulting electric field is coupled with a positive potential applied to the duct that is sufficient to steer most of the ions around the duct. One can use this technique to deposit defect-free thin films of metals, alloys, nitrides, carbides, or carbon. McKenzie also collaborates with Japanese researchers M. Murakawa, S. Miyake, and S. Watanabe at the Nippon Institute of Technology on the characterization of cubic boron nitride (CBN) films. According to McKenzie, only the Japanese workers have been able to successfully prepare cBN films; there are no reports of production in the United States. These films were prepared by reactive ion plating from a boron evaporation source on a silicon substrate. To achieve good bonding with the substrate, apparently, a titanium interface layer, was introduced. McKenzie is also collaborating with Dr. Amaratunga of the Engineering Department of Cambridge University, United Kingdom, on the deposition of amorphous diamond-silicon semiconductor heterojunctions.

Professor Y.-X. Mai at the Engineering Department of the University of Sydney is well recognized for his work on the fracture mechanics related to the modeling of the indentation technique for determining the fracture toughness of ceramics. He is also contributing regularly in the area of micromechanics of interfaces in ceramic composites.

At the invitation of Dr. Michael Swain, I visited the CSIRO Applied Physics Laboratory, which is also the

site of the National Measurement Laboratory, which is very well equipped with state-of-the-art instrumentation for precise measurement of physical properties of materials as well as developing standards. There is considerable activity on the development of new and improved instruments. For example, an ultramicro indentation system for investigating plastic and elastic properties of coatings and near-surface materials has been developed and is being marketed internationally. The laboratory is also involved in advanced development of electronic materials and devices. Swain showed me the facilities for reactive sputtering and ion plating.

In Melbourne I visited another institute of CSIRO known as the Institute of Industrial Technology. It may be pointed out here that CSIRO is one of the largest and diverse institutions in the world. It has a staff of 7,000 including 2,500 scientists working in some 100 laboratories and field stations throughout Australia. The major objectives of CSIRO include:

• Carry out strategic research that can be applied by Australian industry or government for the community benefit.

• Collaborate with other institutions and industry to strengthen the research effort and ensure its transfer and application.

• Lead and promote an expanded science and technology effort in Australia.

At the Institute of Industrial Technology, major programs include ceramic powders such as those of zirconia, glasses, carbon fibers, ceramic composites, high

superconducting materials, fuel cells, etc. The significant contributions of this institution include the development of processes for the manufacture of zirconia powders and the transformation toughening of ceramics. Zirconia

powders, partially stabilized zirconia, and zirconium chemicals are being manufactured by Imperial Chemical Industries (ICI) subsidiaries Z-Tech Industries (ICI) subsidiaries Z-Tech Pty Ltd. and Nilcra Ceramics Pty Ltd., Pty Ltd. and Nilcra Ceramics Pty Ltd., which are located very close to the CSIRO laboratory. At the Polymer Division, Dr. Peter Wailes and his associates discussed with me some of the ongoing projects on the special resins that were being developed for use in the ceramic fiber reinforced polymer composites. This group is also collaborating with the Institute of Industrial Technology, where a pitch-based carbon fiber is being developed at the pilot plant scale.

Monash University, which is located in the vicinity of the CSIRO laboratories, is essentially an undergraduate engineering school. Its Materials Sciengineering school. Its Materials Science Department is headed by Professor Paul Rossiter, who has been successful in establishing a Center for Advanced Materials Technology, which serves as a service laboratory to members of a consortium that includes four universities, one DSTO laboratory, and some industrial concerns. The center aims to provide an Australian focus for the generation of advanced aerospace technologies that will foster the development of an efficient and globally competitive aerospace industry.

Another research institution in the area is the BHP Research Center. BHP is one of the largest industrial complexes in Australia. With a capacity of 7 million tons a year, BHP is Australia's 7 million tons a year, BHP is Australia's major steel producer and is one of the leaders in continuous casting technology. BHP's Melbourne Research Laboratory, also known as MRL, supports the steel group's activities with R&D in steel processing and product development. Major programs involve the development of models for the prediction and control of solidification behavior in slab, bloom, and strip castings and the pilot scale simulation of continuous casting for optimizing conditions for the production of high quality

steel. The laboratories are equipped with the necessary equipment for studying experimental alloy melting, casting, and thermomechanical processing and characterizing the composition and metallurgical and crystallographic structure. The structural engineering group studies the behavior of steel and composite structural elements for the development of design codes for composite slabs and other elements. Research is also in progress on other advanced structural materials including high molecular weight polyethylenes, sialon, silicon carbide, whisker-reinforced ceramics, and cutting tools. Another department is engaged in the ground radar probing program of sensing mineral deposits. BHP is also a large producer of oil and gas. Therefore, research programs are addressed at supporting these activities, as well as developing alternate fuels, including synfuel, coal gasification, and catalysis.

Dr. Maurice de Morton was the host at the Materials Research Laboratory of DSTO in Melbourne. I was briefed by the program managers on the progress of their projects since I visited them in August 1990. Noteworthy was the work on the stirling engine, which the MRL scientists are evaluating for their submarine program. A full-scale engine has been imported from Europe and is being evaluated for fuel efficiency and other engine characteristics. At a lunch meeting, Morton discussed administrative matters, including the Australian Government's plans to reduce manpower and funding at the laboratories. He stated that there was pressure on them to bring in funds from outside and to establish collaborative R&D programs with industry.

At the University of Melbourne, I visited the Microanalytical Research Center, which has been recently equipped with high resolution electron microscopes and other surface characterization instrumentation and analysis devices. One of the unique pieces of equipment brought to my attention was

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