ICG expert meeting on Glass Surfaces & Thin Films on Glass

Most, if not all, properties of glass ultimately depend on surface behaviour postulated one of the participants at the 2010 ICG roadmap workshop which took place in Paris at the Institut du Verre, 21 …

Most, if not all, properties of glass ultimately depend on surface behaviour postulated one of the participants at the 2010 ICG roadmap workshop which took place in Paris at the Institut du Verre, 21 Boulevard Pasteur. Some of the leading world experts on glass surfaces and thin films on glass met for a two days workshop to develop a roadmap in that field for the future R&D which will be of most importance for future glass applications. The 18 invited experts came from eight nations, and from both industry and academia; each had special expertise in a different research area. This expert workshop continues the series of meetings organized by the ICG and started in 2008 on the hot spots on glass R&D; results from the previous meetings have been published recently in a booklet MAKING GLASS BETTER: An ICG roadmap with a 25 year Glass R&D horizon edited by Klaus Bange and Marion Weissenberger-Eibl. To initiate and motivate the discussion, each expert had a time slot of one hour that was spilt into a 30-minute presentation followed by 30 minutes for discussion. The speakers were asked to make in their presentations clear but also provocative statements on the types of activities that will be essential in their field. In particular questions were discussed like What topic will be presented as an exceptional success between now and 2025?; What are the future key challenges (till 2025) in this specific field of expertise?; What topic is expected to become a real bottleneck for future developments? and What would be the key breakthrough and when is it likely to occur? Whilst the first day was more oriented towards applications and focussed on the two important fields Glasses for Biomedicine & Pharmacy and Glasses for Energy (generation and saving), the second day concentrated on Thin Film Processes and Fundamental aspects of glass surfaces. As key challenges in the field of biomedicine and pharmacy the experts discussed the different aspects of in vitro reactivity versus in vivo reactivity on glass surfaces; in vitro reactions versus glass composition; the bonding mechanism of bioactive glass to bone; glass surface-protein interactions and various related topics. In the session on glasses for energy applications, the requirements for photovoltaics were described and analysed, and coatings for solar control were discussed in detail. The need of thin and lightweight glasses was addressed as relevant for future applications in that field but also strong and durable glasses are desired. The challenge for coatings in that field was seen mainly as the need for self-cleaning surfaces. The second day focused more on the fundamentals of glass surfaces and thin films. In the glass surfaces session, this included: the impact of boron oxide upon the surface chemistry; the understanding and controlling of environmental effects on tribochemical properties of surfaces; and also some recent results of atomistic simulations of interactions with water. In addition, the role of the substrate on thin film growth was elucidated, the relevance of durable, wear-resistant functional coatings described and the properties of mesoporous nanostructured coatings produced using sol-gel based processes investigated in detail. In the final roadmapping discussion, a fundamental and quantitative understanding of adsorption phenomena on different types of glass surfaces was ranked high but also adhesion and interfacial strength on an atomistic scale, and chemical durability in different environments were seen as important for future applications of glass. Further research on selected glass surfaces is necessary to create a broader experimental database and link these with atomistic modelling activities, i.e. better coordination between the experimental and modelling activities is essential. In the long term, predictive models on the atomistic scale were seen as the tools of the future. This approach is not a short-term action. In a time when many glass producers are stealthily converting to surface processing or coating companies and moving away from the glass community the small and fairly homogenous and coherent group of glass surface scientists have to coordinate their below critical“ research resources. In addition cross cutting and interdisciplinary actions and workshops with surface scientists from other research fields should be organized in the future to speed up progress in the field: glass surfaces and thin films.