Interview: V.G. Kessler

What is your “sol-gel” background?

I was actually very lucky to join the group of Nataliya Turova, one of the internationally recognized pioneers of the chemistry of sol-gel alkoxide precursors, already as undergraduate at the Moscow State University, Russia. I was working mostly on development of new synthetic approaches to precursors and materials, and on solution thermodynamics of precursor systems. My PhD defended in 1990 had a strong focus on reaction mechanisms, especially on halide-free non-hydrolytic transformations offering crystalline oxide nanoparticles directly in solution. I felt I needed better insight into characterization of both precursors and materials, so I made 3 postdocs – first at the X-ray Center of the Russian Academy of Sciences, studying crystallography with Dr. Alex Yanovsky and Prof. Yurii T. Struchkov, second at the University of Nice-Sophia Antipolis, in France, focusing on NMR characterization with Prof. Liliane Hubert-Pfalzgraf, and finally I worked with materials characterization at Stockholm University with Prof. Mats Nygren. I have taken then a chance to start an own research group aimed at sol-gel materials for environmental applications at the Swedish University of Agricultural Sciences in Uppsala in 1997, where I later got Full Professorship in 2004.

What are the main topics you are working on today?

We are working on a whole spectrum of precursor directed synthetic approaches with major focus on three domains: dense oxide coatings for corrosion protection, porous solids, especially hierarchically porous metal oxides, for environmental catalysis, bioencapsulation and drug delivery applications, and also – back to my roots – solution produced crystalline nanoparticles for bioimaging, photocatalysis and drug delivery. The major scientific challenges we see are, in the hydrolytic routes, the choice of modifying ligands, permitting to control and direct aggregation of primary colloid particles, generated by hydrolysis-condensation, and, in the non-hydrolytic routes, the choice of ligands, solvents and thermal conditions to control crystallinity, size and also the surface chemistry of the produced nanoparticles.

The collaborations you have initiated?

I guess, I should be an easy person to collaborate with – it is at maximum a quarter of my group’s production, may be even less, which is not made in some collaboration, interdisciplinary or international, or both. The most important collaborations in sol-gel community have been with Stephane Parola in Lyon on dense oxide coatings, with Yurii Gun’ko in Dublin on synthesis and characterization of crystalline oxide nanoparticles (especially generation of surface chirality), with Nicola Huesing (now in Salzburg), whom we helped with precursors for iron oxide doped ordered silica films, with Henny Bouwmeester and Dave Blank, and, of course, Gerald Spijksma in Twente – we made a tremendously exciting job on zirconium precursors together and succeeded in preparing hydrothermally stable microporous membranes, with Jaap Vente and colleagues at ECN we have advanced further in understanding of the solution chemistry of membrane synthesis, and with Wieslaw Strek in Wroclaw, and his colleagues Robert Pazik, Rafal Wiglusz and Leszek Kepinski we have made a lot on new approaches to luminescent biocompatible oxide nanoparticles. With Jean-Marie Nedelec in Clermont-Ferrand we have worked together on characterization of hierarchical TiO2 and of surface-active complex oxide nanoparticles for drug delivery and catalysis. With Vadim Guliants at the Catalysis Center, University of Cincinnati, USA we have developed mesoporous complex oxide catalysts. Home in Sweden it was the interdisciplinary aspects that dominated and we have worked with Lars Kloo at KTH in Stockholm on theoretical description of precursors, with Ingmar Persson at SLU on EXAFS characterization of precursors and materials, with Sebastian Håkansson and John Stenström at Microbiology Department of SLU – on encapsulation of microorganisms and biomolecules for environmental and food applications, with Lena Palmberg, Sven-Erik Dahlén and Boris Zhivotovsky at Karolinska Institute in Stockholm – on drug delivery materials and biological effects of nanomaterials. The most important collaborations that are both international and interdisciplinary have been with Andrei Shevelkov and his group at MSU on metal-metal bonding in alkoxide clusters, and with Regine Herbst-Irmer in Göttingen on treatment of twinned structures. I am sorry, there have been at least as many collaborations related to other Soft Chemistry Techniques, MOD and MOCVD, and also to more fundamental alkoxide chemistry, to…

Could you let us know the main challenges you foresee for the sol- gel process and the sol-gel materials in the next future?

With the vivid interest in colloid chemistry and synthesis of nanomaterials for environmental and biomedical applications we see today, the sol-gel process and sol-gel materials are in fact entering their golden age now. The true scientific challenges will be in achieving better understanding at both fundamental and applied level of what is happening from the point of view of chemistry and biology at the organic inorganic interfaces and how the new materials are interacting and influencing/are influenced by biological media or leaving organisms. I have strong belief that the planned new COST actions will succeed in receiving EU funding and will open new forum for exchange of insights and ideas to shed light on this topic.

What is your wish for the sol-gel community?

Our society is active, functional and well organized. What we need is, of course, to grow and to involve the tremendously broad new generation of materials scientists that do great job on nanomaterials, not realizing that it is sol-gel technology they are working with, just like a hero in Moliere’s play did not realize he was speaking in prose. We need to reach these people both thematically and geographically and help them to find their way into our community. I look forward with great expectations to our next International Conference in China and hope to find new colleagues and meet many new members of our society there.