Chemical functionality specific to the nanometer scale

Obiettivo

A.GENERAL BACKGROUND

A.1.Why a COST action for this topic?

In recent years chemists have focused their interest towards designing new functional materials whose properties depend on the specific organisation the molecules. This has opened a new type of Chemistry. Methods are all different from the classical approach, where a change in properties would be obtained by introducing new functional groups: properties can be modified by cluster or grain sizes, by organisation in different phases, and by supramolecular and nano-scopic molecular alignment.

Supramolecular Chemistry, molecular self-assembly, molecular recognition and sensing have been made subjects of scientific actions.

The focus of the present action it is not the mechanism of organisation that is the subject, but the influence on properties that may be observed due to these ways of organisation. The methods to observe and subsequently to create and to control those structures at nano-metric scale have only been available for a few years. Therefore the interplay of these methods and

the link to chemists which may prepare new systems adapted to the nano-structures is only now taking place. The development of theories, modelling, characterisation techniques and synthesis will have to be linked in order to obtain the important results rapidly. Nano-Chemistry therefore offers a unique opportunity for establishment of a COST Action, which will promote Chemistry. The proposing group has been cautious to use the name Nano-Chemistry, since it is wide open to interpretations. A better definition was found to be Chemical functionality specific to the nano-meter scale. Here it is emphasised that the chemical function shall be influenced by the aggregation of molecules on the nano-meter scale. No definite length scale can be given since different properties will show different sensitivity to the size of aggregates.

The results to be obtained as consequence of the COST Action will be of fundamental importance for future technologies. The European survey precluding this proposal point to chemical sensing and to separation technologies as likely activities to benefit from the work in the first stage. In a later stage coating technology, and many aspects of medicine and biotechnology may be influenced. Many parts of the chemical production technologies will also be influenced by the requirement for ultra-pure materials in quantities much smaller than for present productions.

A.2.Status of the research in this field

Research and development on the formation of nano-structured materials and complex molecular systems is rapidly expanding and there is a wide range of disciplines contributing

to this field. Besides the synthesis and control of materials in the nano-meter dimensions, in a second stage, the focus is directed towards the development of systems and devices which take advantage of the chemical and physical principles where causes are found in the nano-meter scale. New properties and functions are realised by hierarchically organisation of materials in discrete steps ranging from the atomic to the macroscopic scale. Thus, a higher level of complexity is reached by combination of smaller functional entities. However, there is little understanding of the interrelations between structure and properties of such complex systems in which the chemical reactivity, molecular recognition, catalytic efficiency are affected by a nano-structured arrangement. This effect of an organised surrounding on the chemical functionality as it is well established in biology - e.g. in the case of enzymes, photosynthetic systems, immune agents, membrane complexes (ion channels and pumps) protein folding (chaperonius) molecular motors - cannot be predicted from the properties of the constituent activities.

Present impact of nano-structured materials is concentrated on dispersions and coatings (thermal and optical barriers, inkjet materials, information recording layers and wear resistant coatings) high surface area materials (e.g. drug delivery, tailored catalysts, absorption/desorption materials) consolidated materials (low-loss soft magnetic materials, glassy metals, nano-composites) and bio-catalysis (immobilised enzymes, antibodies).

The major challenges in this area besides the dimensional control regard the long term and chemical stability. We need to know not only the structures of the surfaces and interfaces and how we can tailor them but also their local chemistries and the effects of interaction between the nano-scope structures and their surroundings. In particular in the case of molecular (soft) nano-materials small external changes can cause a strong response. The energy scales are of the order of the thermal excitation and atropic forces play a major role. The relevant dynamical processes are often slow and must study using specific experimental techniques. Corresponding to the physical size effects also a number of chemical functions have been identified to be clearly size and structure dependent, e.g. electro-chemical processes, sensing adsorption and separation of molecules and in specific cases the catalysis of chemical reactions.

Improved knowledge in this field will be required for the more complex systems and devices. This will be developed in the future, i.e. sizing and separation of specific molecules, self-organisation of complex structures, multifunctional surfaces and coatings, molecule specific sensors, chemical amplification, sequencing and templating of single molecules, information storage, nano-reactors for new chemical selectivity.

Today capabilities for synthesis of large molecules are rapidly growing. The methodology to identify and to purify the synthetic macromolecules is not developed. As a consequence the experiments frequently are performed on poorly defined samples. The technologies to manipulate and to position the macromolecules or aggregates are still in its infancy and many new tools have to be devised.

For many properties the size dependence will result in new theories which will have to be established and later exploited in new nano devices. In sensing and recognition several new concepts will emerge based on spontaneous shape recognition. Also refinements of molecular imprinting along this lines may result in vastly improved detection capabilities in health and environment problems. The ability to manipulate and orient macro and biomolecules may improve sensitivity and selectivity for many already known systems that can be perfected using the full control of location and orientation in preparation of films.

In particular in sensing and recognition several new concepts will emerge based on spontaneous shape recognition and refinement of molecular imprinting may result in vastly improved detection capabilities in health and environmental problems.

A.3.Relationship with other European programmes

The definition adopted here of nano-Chemistry makes the COST Action closely related to a number of running actions. The difference may be exemplified by COST D9 where computational methods in Chemistry are addressed. The action on Nano-Chemistry will benefit tremendously from the availability of advanced computational methods. In the proposed action it is however the use of the methods to calculate and simulate the properties dependent on aggregate sizes that will be in focus. This is most often a problem that purposely is avoided in many standard calculations. Similar relations are found to D10, D11, D14 and D15. The materials program 523 can be seen as encompassing nanoscience in general among other subjects. The 518 action in COST is promoting "smart" materials.

Inside the 5th framework programme of the European Union, synergies would be promoted with the activities of GROWTH, generic research for industrial sustainable development.

The intensive interest in nano-Chemistry justifies however that this subject is devoted by a separate Action.

B.OBJECTIVES OF THE COST ACTION AND SCIENTIFIC CONTENT

B.1.Main objective

The main objective is to investigate the effect of nanostructural features on chemical properties.

There is particular interest in answering questions such as "How are chemical reactivity or selectivity influenced by the size, shape or ordering of the pores or of the particles themselves?" "How does the ordering of molecules or macromolecules in the pores influence these properties?"

Since the provisions of answers to these questions require a wide range of techniques, a fundamental, interdisciplinary approach is recommended. The materials studied are of prime importance and have to be chosen with respect to the respective chemical functionality/ functionalities together with the corresponding application in question.

B.2.Sub-topics

Different types of chemical functionality expected to be influenced by nano-structural features, i.e. size, shape, ordering in the nano-meter range. Many of the following functionality are closely linked to (bio)sensing and separation.

1.Chemical reactivity, chemical selectivity

It is possible to consider nano-structures as nano reactor, which offer the possibilities to control, mass transport and reaction dynamics as well as chemical equilibria. Therefore also the functionality of nano objects formed inside these reactors can be influenced. Electrochemical properties like redox potentials, kinetic barriers, stability against oxidation and reduction are significantly influenced by size. This effect can be used in both electrochemical synthesis of nano-scale materials and the development of electrode materials for fuel cells and batteries, but also in the development of nano-structured surfaces for sensor applications and single electron devices (molecular electronics). Other concepts involve the realisation of reaction and process (recognition - chemical reaction - transport - analysis) sequences at neighbouring sites of a given nano-structure.

2.Site and shape selectivity, chemical recognition

In particular for this COST ACTION, site and shape selectivity in relation to separations and chemical recognition can be considered since designing nano-structures opens up possibilities to tailor host sites, including cavities, which may bind metal-containing species or molecules with well defined shapes at specific sites. Molecularly imprinted polymers, mesoporous materials based on silica, or lipid membranes with active carriers can be named as examples. Thus separations and specific recognition sites may be introduced for a wide range of chemical species from metal complexes to proteins. By varying the size of objects in the nano-meter range adsorption/desorption equilibria and kinetics can be influenced.

3.Chemical sensitivity

Since nano-scale objects are highly sensitive to changes in their environment, it might be possible to design materials, which open up possibilities to detect very small quantities of interacting species.

4.Chemical nano-actuators, chemical switches

Attaching captors who influence the interaction with absorbates/guest species can modify Nano objects and their properties. Also switching the properties - in this case chemical functionality - by light, electric fields, heat, or solvents is possible in the context of nano-scale materials.

5.Chemical stability

Owing to their large surface areas and changed redox potentials nano-particles in general are easier oxidised and/or hydrolysed. Therefore in many cases strategies of stabilising these species have to be developed.

In this COST action it is not required to manufacture a device whose function is based on the chemical functionality listed above. However, the technical application(s) considered should be defined.

The COST action is focused on chemical functionality. Materials, synthesis, characterisation, and modelling are to be considered in relation to the functionality in question:

- Sub-topic 1: Synthesis and Preparation to create nano objects

There is a broad spectrum of synthesis and preparation methods to create nano objects:

- Self assembly
- Imprinting
- Soft Lithography
- Micro contact printing
- Controlled mineralisation
- Template synthesis
- Laser ablation
- Precipitation in microemulsions
- Electrochemical methods
- Sol-gel processes
- Gas condensation

With respect to this Action it is important that the preparation permits the variation, or control, of the nano-structure. Among the many nano objects, which can be prepared by the methods mentioned above one, has to name

- Nano/mesoporous materials
- Thin films
- Imprinted polymers
- Self-assembled mono-layers
- Inorganic particles
- Dendrimers
- Coordination oligomers
- Nano-wires and nano-tubes

- Sub-topic 2: Characterisation of functionality

Analytical techniques with high spatial resolution, which give information on chemical functionality, host-guest interactions and architectures may have to be optimised and adapted to the respective material and property. However, the development of new techniques is not a major goal of this COST action. The methods to be applied are well known in principle, e. g.

- Surface wave analysis
- Surface plasma resonance
- Scanning probe techniques
- Electron microscopy
- Light scattering techniques
- Quartz micro balance
- Absorption spectroscopy
- Fluorescence spectroscopy
- Single molecule spectroscopy
- Photo-electron spectroscopy.

Special attention should be paid to time resolved and in-situ techniques.

- Sub-topic 3: Modelling, simulation methods and prediction of functionality

Theoretical calculations, modelling and simulation methods permit the prediction of functionality of the respective nano objects and complex aggregates with respect to mechanisms of formation, structure and application.

Concerning the formation of the nano objects it is important to model

- Brownian motion, especially in restricted space,
- two-dimensional processes, or
- reaction kinetics, especially at surfaces of large substrates, particles and pores etc.

In this context semi empirical methods but also quantum mechanics (density field theory) will be used. Concerning the use and application of nano objects of controlled functionality,

- adsorption properties,
- surface properties,
- size effects,
- mesogenic effects,
- photochemical properties etc.

Have to be modelled, e. g. by molecular dynamics.

C. SCIENTIFIC PROGRAMME

The scientific programme will depend on the projects submitted by individual research teams. The working group projects will be selected according to the objectives outlined above. At this stage there is no specific scientific programme suggested for this action in order to place no limitations on the invited proposals. The selection will strictly occur according to the outlined objectives.

D.ORGANISATION AND TIMETABLE

D.1.Organisation

Research projects fitting in the subtopics described in section C will be submitted by scientists to the Management Committee members.

This Committee will establish contacts between scientists.

The Management Committee has responsibilities for:

1. Drawing up the inventory during the first year, organisation of workshops and start of the activity; existing contacts will be used which should greatly facilitate this task.

2. The coordination of the joint activities with other COSTS Actions; joint meetings are likely to result from this activity.

3. Exploration of wider participation and exchange of information with EC specific programmes, ESF, etc.

4. Planning of the intermediate report, the final report and the concluding symposium.

Progress in each of the projects will also be reported by the respective participants in their own countries within the framework of existing programmes.

D.2.Reports

The progress of the programme will be monitored by brief annual reports from each of the participating scientists. The reports will describe the results of research obtained through scientific coordination. A milestone report ought to be prepared by the Management Committee after 2 years of joint activities. The report will be presented to the COST Technical Committee for Chemistry for their review.

A final report will be published to inform scientists' non-participant and research workers interested in the results about the scientific achievements of the Action. It is expected that some reviews by participants will describe the progress made and state of the field will be published in International Journals. To conclude the COST Action, a symposium will be held after 5 years who will be accessible to other scientists.

D.3.Timetable

The Action will last five years and comprise the following four stages:

Stage 1:After the first meeting of the Management Committee, a detailed inventory of ongoing research and existing plans of the participating groups to begin joint projects will be made. This will result in a discussion document. This will allow further planning to occur.

Stage 2:It will be evident which projects are closely related and would benefit from joint activities. Researchers (and co-workers) will set up (and continue) joint collaborative projects and exchange their recent research results. It may be appropriate to explore wider collaboration with other European countries during this stage.

Stage 3:An intermediate progress report will be prepared after 2 years for review by the COST Technical Committee for Chemistry and by the COST Senior Officials Committee.

Stage 4:This final phase will begin after 4 years and will involve the evaluation of the results obtained. It may include the organisation of a symposium for all the participants and co-workers. The final report will be submitted to the COST Technical Committee for Chemistry for a scientific assessment and after to the COST Senior Officials Committee.

E.ECONOMIC DIMENSION

At the moment there are few commercial uses for the materials described so far. However, the materials are still being studied at the precompetitive stage and may well have significant potential within Europe for separations and molecular recognition.

The economic dimension of the Action (initial estimate of total costs = personnel + operational + running + commission costs) is: EUR 60 million.

The human effort in the area of "Chemical functionality specific to the nano-meter scale", as described in this document, amounts to 400 man-years (80 researchers during 5 years), being equivalent to EUR 40 million approximately.

E.1.Personnel costs

Estimates of personnel costs (research + administration) will depend on the rates applicable for various EU countries (one man-year = EUR 100 k.

Estimates of personnel costs (research + administration) are as follows:

Sub-topic 1: in about 20 countries a total of 100 man-years, totalling EUR 10 million
Sub-topic 2: in about 20 countries a total of 200 man-years, totalling EUR 20 million
Sub-topic 3: in about 20 countries a total of 100 man-years, totalling EUR 10 million

E.2.Operational and running costs

The estimate of the total operational and running costs including costs of instruments and materials is EUR 20 million.

E.3.Coordination costs

The costs of coordination to be covered by the COST budget are estimated at EUR 60 000 per year, i.e. a total of EUR 300 000 for the five years duration of the project. (i.e.: 0,5% of the total cost of the research co-ordinated).

F.DISSEMINATION OF SCIENTIFIC RESULTS

All publications arising from research carried out under COST Action D19 will credit COST support and the Management Committee will encourage and promote all co-authored papers. Results of research carried out by the working groups under COST Action D19 will be submitted to international scientific journals and reviews.

Joint meetings among different working groups in COST Action D19 and with working groups from other COST Actions, particularly with those of COST Action D11, D14, D15, will be organised in such a way as to best promote interdisciplinary communication.
The Management Committee (MC), in conjunction with the working groups (WG) of the Action, will meet one meeting every year with the main aim of presenting results to the MC as a whole and, where possible, the MC will invite potential users and interested parties to this meeting.

The Management Committee will, during the first year of the Action, also set up a work plan for interdisciplinary events for the dissemination of results of the COST Action D19.

G.DURATION OF THE ACTION

The Action will last for five years: 2000-2005.

Invito a presentare proposte

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Meccanismo di finanziamento

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Coordinatore

N/A

Contributo UE

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Indirizzo

Costo totale

Nessun dato

Obiettivo

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Programma(i)

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