organised by College 9
Tuesday 23 June, 2026 at 11h00
Seminar room 110-111, ILL 50, 1st floor
Zoom link: https://ill.zoom.us/j/95581858117?pwd=hh9paEQj6BF8u9WYzfZkvZaGspe1i3.1
Passcode: 078610
"Structure formation in paints and coatings"
Professor Lucas Goehring,
Nottingham Trent University (UK), lucas.goehring@ntu.ac.uk
Paints and coatings are typically a mix of small particles, like pigments, along with a polymer glue or binder. Similar products include inks, varnishes, cosmetics, ceramics and even the lithium-ion battery electrodes that power modern electric vehicles. These materials are prepared as a liquid, spread over a surface, and dried. As anyone who has painted a wall will know, however, this process can easily go wrong. Even a well-prepared paint can develop an undesirable skin and wrinkle, crack, or peel, and these coatings can also visibly degrade over time.
In this talk I will go through the key stages of film formation, or how a colloidal dispersion dries. I will show how small angle scattering experiments (SANS/SAXS) helped to elucidate how the structure of the film changes during drying, evolving from a dilute gas of particles, into a transient gel where capillary pressures balance electrostatic repulsion, to a final aggregated solid. I will then turn to look at how the insight gained has led to a better understanding of mechanical instabilities like fracture, shear banding, birefringence, and peeling, as well as revealing an unexpected route to colloidal crystallisation.
Finally, I will summarise our recent work using neutron scattering techniques to investigate blanching, a degradation process that can cause a visible whitening in the traditional varnishes that are used as a protective outer coating on many historically and artistically important paintings.
Speaker’s website: https://www.ntu.ac.uk/staff-profiles/science-technology/lucas-goehring
Orsolya Czakkel (College 9 Secretary)
External visitors may ask for a site access to tellier(at)ill.fr