报告题目:Polymer-surface interactions from the molecular perspective by AFM force spectroscopy
G. Julius Vancso studied physics and materials science at the University of Sciences Eötvös Loránd Budapest, Hungary, and at the Swiss Federal Institute of Technology (ETH-Zürich), and holds a PhD in solid state physics. Following a tenured faculty appointment at the University of Toronto in the Department of Chemistry he joined the University of Twente in the Netherlands as Full Professor, in 1994 and is ever since Professor and Chairholder in Polymer Materials Science and Technology.
His current research interests involve materials science of “smart” polymers for applications in biomaterials, medicine, fluidics and sensing; single molecule studies; surface engineering with macromolecules; and materials chemistry of organometallic polymers. He was visiting professor at the following institutions: University of California at Santa Barbara, Technical University of Budapest, Technical University of Catalonia in Barcelona, and the Swiss Federal Institute of Technology (ETH- Zürich). In Twente he held various administrative functions, including Associate Dean for Chemical Engineering.
He has been government advisor of Singapore between 2001-2005, and Visiting Principal Investigator of the Agency for Science, Technology and Research (A*STAR). Following completion of this program, he has been appointed to Adjunct Professor at Nanyang Technological University in Singapore.
Professor Vancso is Fellow of the UK Royal Society of Chemistry, and external member of the Hungarian Academy of Sciences. He published over 520 papers, which earned him over 11,500 independent citations and an h-factor of 53. He is co-inventor of 7 patents, and co-owner of Aerotech Ltd., a spin-off company which focusses on nanomaterials. He is Senior Executive Editor of European Polymer Journal since 2002.
Adsorption of polymers at surfaces is a central subject in polymer science with great relevance for many applications related to surface functionalization, nanofabrication, fouling, colloidal stabilization, coatings and adhesives, etc. AFM based force spectroscopy approaches, which have been used with success to measure forces down to the level to single molecule interactions, have been used with success to study adsorption and binding strength, conformation, and supramolecular structure of surface attached polymers. In this presentation, following a short introduction into force spectroscopy by AFM, two examples will be used to show recent progress in this area obtained in our laboratories. First we present results related to measuring the isoelectric point (pI) of proteins immobilized at AFM probe surfaces, using designer reference substrates with controlled charge over a broad pH range . We validated our approach using proteins with well-known structure and ionization behavior. This approach allowed us to determine pI values of still unsequenced and poorly characterized “temporary adhesion” proteins of barnacle cyprids, relevant for marine fouling, and available in minute amounts only. In the second example we focus on single polymer pull and show the first results related to direction dependence of the adhesion force for partially adsorbed chains, when the free end is pulled. We demonstrate direction-dependent chain pull and fingerprints in the adhesion force vs. pulling angle dependence indicating adsorption-desorption transitions as a function of the pulling angle . A short account on anticipated future developments will conclude the presentation.
 S. Guo, X. Zhu, D. Janczewski, S.S.C. Lee, T. He, S.L.M. Teo, G.J. Vancso, Nature Nanotechnology, 11, 817 (2016)
 L. Grebíková, H. Gojzewski, B.D. Kieviet, M. Klein Gunnewiek, G.J. Vancso, submitted.