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Chemically modified surfaces symposium
XI
trends’inanalyticalchemktry, vol. 6, no. 8,1987
Chemically modified surfaces
A meeting entitled Chemically Modified Surfaces Symposium was held 17-19 June, 1987, in Fort Collins, CO, U.S.A. Forty-two papers and eleven posters were presented to approximately 105 participants, nearly one third of whom were from Canada, Britain, Europe, or Asia. This was the third such meeting with coorganization between Prof. D. E. Leyden, Colorado State University, and W. T. Collins, Dow Corning Corporation, Midland, MI, U.S.A. Previous meetings were in Midland, MI, U.S.A. (1978) and Snowmass, CO, U.S.A. (1985). The theme of these meetings are topics dealing with the science and technology of the preparation, characterization and application of materials prepared by surface modification. Proceedings will be published. This year session topics were biomaterials, catalysis, surface characterization, surface modification in electronics, and a general session. The plenary speaker, Nobel Laureate Professor R. B. Merrifield, presented a review and new information concerning the use of solid phases in peptide syntheses. The keynote speaker for the session on biomaterials, C. R. Lowe, presented fascinating new information on biosensors based on a variety of semiconductor, optoelectronic and other principles. New examples of immobilized enzyme-catalyzed reactions for analytical purposes were given. For example, Professor, J. Stamberg (Prague, Czechoslovakia) described the use of modified bead cellulose support for the treatment of suppurating wounds. The topic of immobilized catalysts is one of high interest in many fields of industry and technology. The keynote speaker for the session on catalysis, G. A. Ozin, described exciting new methods of metal vapor tech-
niques for the fabrication of organometal liquid polymers, liquid poly mer stabilized metal clusters and colloids. The electronic, magnetic and electrocatalytic properties are attractive for a variety of applications. Several papers presented new results on metal cluster catalysts, organometallic compounds on oxide substrates, polymers, macromolecules and electrode surfaces. The session demonstrated the diversity of effort in the attempts to develop new and more effective catalytic and electrocatalytic materials. Surface characterization takes a variety of forms. The keynote speaker, J. T. Yates, presented a truly exceptional paper entitled ‘Interactional effects in the chemisorbed layer’. The principle technique employed in this research is electron stimulated desorption ion angular distribution (ESDIAD). The method is capable of generating images of the angular dependence of ion emission from molecules under electron bombardment. Because the ion emission depends upon the incidence angle of electrons relative to bond direction, orientation of molecules on a crystalline surface may be deduced, and the influence of surface concentration, temperature and other parameters on the molecular interactions with the substrate and/or neighboring molecules may be investigated in detail. Three papers were presented which gave new results and further demonstrated the potential of solid-state NMR with cross polarization and magic angle spinning (CPNAS) for the investigation of modified surfaces. A session on surface modification in electronics was very diverse in content. The keynote speaker, M. S. Wrighton, presented new work on the preparation of microelectrodes with surface dimensions of approximately 1 pm. By means of single or multiple surface modification, these electrodes become microelectrochemica1 ‘transistors’ or ‘diodes’. Solid state versions of these devices can be made to respond selectively to cer-
tain gases. C. M. Elliott presented results of a polymer modified electrochemical electrode in which metal complexes were incorporated with up to seven oxidation states ranging from 2+ to 4-. These materials show dramatic electrochromic behavior with extensive change of color at each oxidation state. A variety of other applications of surface modifications in electrochemical or electronic devices were described. A general session, organized by R. L. Yates, included reports of laser techniques for surface modification of polymers, and metals. These reports showed dramatic changes in surface characteristic in some cases. It is clear from these reports that laser methods of surface modification have a promising future. G. L. Richmond presented an excellent report of the use of second harmonic generation for the in situ investigation of metal electrode interfacial phenomena. This paper was somewhat a preliminary report, but shows much promise and stimulated considerable interest. From the comments of the participants one judged the meeting to be both a scientific and social success with ample opportunity for interaction.
DONALD E. LEYDEN
Professor Donald E. Leyden is at the Department of Chemistry, Colorado State University, Fort Collins, CO 80523, U.S.A.
Reprints We can supply reprints of any article in TrAC at very reasonable rates, (minimum order 100). Please apply for details to: TrAC Editorial Office P.O. Box 330 1000 AH Amsterdam The Netherlands
trends’inanalyticalchemktry, vol. 6, no. 8,1987
Chemically modified surfaces
A meeting entitled Chemically Modified Surfaces Symposium was held 17-19 June, 1987, in Fort Collins, CO, U.S.A. Forty-two papers and eleven posters were presented to approximately 105 participants, nearly one third of whom were from Canada, Britain, Europe, or Asia. This was the third such meeting with coorganization between Prof. D. E. Leyden, Colorado State University, and W. T. Collins, Dow Corning Corporation, Midland, MI, U.S.A. Previous meetings were in Midland, MI, U.S.A. (1978) and Snowmass, CO, U.S.A. (1985). The theme of these meetings are topics dealing with the science and technology of the preparation, characterization and application of materials prepared by surface modification. Proceedings will be published. This year session topics were biomaterials, catalysis, surface characterization, surface modification in electronics, and a general session. The plenary speaker, Nobel Laureate Professor R. B. Merrifield, presented a review and new information concerning the use of solid phases in peptide syntheses. The keynote speaker for the session on biomaterials, C. R. Lowe, presented fascinating new information on biosensors based on a variety of semiconductor, optoelectronic and other principles. New examples of immobilized enzyme-catalyzed reactions for analytical purposes were given. For example, Professor, J. Stamberg (Prague, Czechoslovakia) described the use of modified bead cellulose support for the treatment of suppurating wounds. The topic of immobilized catalysts is one of high interest in many fields of industry and technology. The keynote speaker for the session on catalysis, G. A. Ozin, described exciting new methods of metal vapor tech-
niques for the fabrication of organometal liquid polymers, liquid poly mer stabilized metal clusters and colloids. The electronic, magnetic and electrocatalytic properties are attractive for a variety of applications. Several papers presented new results on metal cluster catalysts, organometallic compounds on oxide substrates, polymers, macromolecules and electrode surfaces. The session demonstrated the diversity of effort in the attempts to develop new and more effective catalytic and electrocatalytic materials. Surface characterization takes a variety of forms. The keynote speaker, J. T. Yates, presented a truly exceptional paper entitled ‘Interactional effects in the chemisorbed layer’. The principle technique employed in this research is electron stimulated desorption ion angular distribution (ESDIAD). The method is capable of generating images of the angular dependence of ion emission from molecules under electron bombardment. Because the ion emission depends upon the incidence angle of electrons relative to bond direction, orientation of molecules on a crystalline surface may be deduced, and the influence of surface concentration, temperature and other parameters on the molecular interactions with the substrate and/or neighboring molecules may be investigated in detail. Three papers were presented which gave new results and further demonstrated the potential of solid-state NMR with cross polarization and magic angle spinning (CPNAS) for the investigation of modified surfaces. A session on surface modification in electronics was very diverse in content. The keynote speaker, M. S. Wrighton, presented new work on the preparation of microelectrodes with surface dimensions of approximately 1 pm. By means of single or multiple surface modification, these electrodes become microelectrochemica1 ‘transistors’ or ‘diodes’. Solid state versions of these devices can be made to respond selectively to cer-
tain gases. C. M. Elliott presented results of a polymer modified electrochemical electrode in which metal complexes were incorporated with up to seven oxidation states ranging from 2+ to 4-. These materials show dramatic electrochromic behavior with extensive change of color at each oxidation state. A variety of other applications of surface modifications in electrochemical or electronic devices were described. A general session, organized by R. L. Yates, included reports of laser techniques for surface modification of polymers, and metals. These reports showed dramatic changes in surface characteristic in some cases. It is clear from these reports that laser methods of surface modification have a promising future. G. L. Richmond presented an excellent report of the use of second harmonic generation for the in situ investigation of metal electrode interfacial phenomena. This paper was somewhat a preliminary report, but shows much promise and stimulated considerable interest. From the comments of the participants one judged the meeting to be both a scientific and social success with ample opportunity for interaction.
DONALD E. LEYDEN
Professor Donald E. Leyden is at the Department of Chemistry, Colorado State University, Fort Collins, CO 80523, U.S.A.
Reprints We can supply reprints of any article in TrAC at very reasonable rates, (minimum order 100). Please apply for details to: TrAC Editorial Office P.O. Box 330 1000 AH Amsterdam The Netherlands