"Sol-gel-based nanostructured coatings, processing by dip-coating and characterization by ellipsometry" by David Grosso

Seminar by David Grosso, professor at IM2NP, Marseille

Abstract

Complex hierarchical nano structured (hybrid) coatings can be achieved when combining chemical advanced bottom-up strategies, such as self-assembly and sol-gel chemistry, together with liquid solution processing. Amongst them, dip-coating is an extremely versatile tool to prepare coatings of various chemical compositions and structures from liquid solutions and has been used for many decades without taking advantage of its whole potentiality. This communication reports first on the recent implementations of the dip-coating process, including controlled atmosphere, capillary deposition, thickness gradient, deposition from supernatant, angle dependence deposition, and single side deposition. Besides, in most applications, sol-gel coatings interact with the ambient atmosphere and physical-chemical properties may be altered through temperature and humidity variation or adsorption of volatiles species present in the surrounding medium. Such phenomena are difficult to assess and it will be demonstrated that ellipsometry is not only a technique adapted to deduce optical constant and physical thickness of optical layers, but is also highly appropriated to the determination of adsorption/desorption mechanisms. Finally, many microfabrication tools can be used to further process the coating and obtained controlled patterns, amongst which soft-nano imprint lithography (Soft-NIL) has proven to be simple to apply to the as-prepared xerogel. This approach will be discussed in terms of adjustment of critical processing parameters and applications in controlled wetting, photonics and gas detection will be presented.  

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[4] T. Bottein et al. Environment-controlled sol–gel soft-NIL processing for optimized titania, alumina, silica and yttria-zirconia imprinting at sub-micron dimensions, Nanoscale, 2018, DOI: 10.1039/C7NR07491C.
[5] T. Bottein, et al. "Black" Titania coatings composed of sol-gel Imprinted Mie resonators arrays. Adv. Funct. Mater. 2016 (DOI: 10.1002/adfm.201604924).
[6] M. Naffouti et al.  Complex dewetting scenarios of ultrathin silicon films for large-scale nanoarchitectures. Science Advances 2017, 3, 1472.
[7] E. Bindini et al. Critical Role of the Atmosphere in Dip-Coating Process. ACS J. Phys. Chem. C, 2017, 121, 14572-14580.
[8] T. Bottein et al. Full Investigation of Angle Dependence in Dip-Coating Sol–Gel Films. ACS J. Phys. Chem. B, 2017, 121, 6220-6225.
[9] M. Faustini, et al. Dynamic Shaping of Femtoliter Dew Droplets. ACS Nano, 2018, 12, 3243.

David Grosso was appointed full-professor in 2007 at the University of Paris. He led the team working at the interface between Chemistry and Processing at the Laboratoire Chimie de la Matière Condensée de Paris (UPMC-Collège de France) where most of his achievement concerned nanostructured thin films and aerosol materials prepared through liquid processing approaches. From 2015, he received a "Chair of Excellence" grant at the university Aix Marseille to develop nanofabrication methods at the interface between top-down and bottom-up approaches. From 2017 he started to lead the NOVA team at the Institute of Microelectronic, Materials and Nanosciences of Provence (IM2NP). Today his work focalises on micro and nanopatterned sol-gel coatings for applications in gas sensing and photonics. His work was awarded by the International Sol-gel Society in 2005 and by the French Society of Chemistry in 2009. He was a junior member of the French Institute of University from 2009 to 2014, and he is co-founder of two start-ups. His track record: 192 publications (H-index 56), 25 patents, 40 invited conferences, 20 supervisions of PhD students.