Agenda

prof. Raymond Phaneuf, University of Maryland - DAIS

The seminar will take place on Zoom https://unive.zoom.us/j/85845693039

Abstract:
Atomic layer deposition (ALD) of certain thin films provides a seemingly near-ideal approach toward the protection of a wide range of cultural heritage objects, combining optical transparency, high conformality and thus resistance to corrosive gases and reversibility. In this talk I’ll discuss two examples illustrating the capabilities and limitations of this method toward cultural heritage conservation: objects crafted from silver and from glass. We find amorphous aluminum oxide ALD films to be a more effective diffusion barrier to corrosive compounds, notably H2S, than cellulose nitrate lacquer films, which are commonly used to protect silver, while minimally changing object appearance. Standard surface characterization techniques were used to determine the effect of the ALD application and removal on the silver surface, and sulfur diffusion through ALD films.  I’ll also discuss the reversibility of such a coating process, an important consideration for art conservation.
The application of such films to glass conservation is more complex-while we find amorphous alumina to be capable of slowing water-mediated corrosion by at least an order of magnitude, the performance of these films is not limited by simple interdiffusion but instead by delamination, suggesting the presence of defects in the films related to their growth mode.

Bio Sketch:
Ray Phaneuf is a Professor and Past Interim Chair in the Materials Science and Engineering Department at the University of Maryland. He joined the University of Maryland in 1985, where he used electron diffraction to study phase transformations on stepped Si(111) surfaces, resulting in the identification of a thermodynamically driven faceting associated with the formation of the (7x7) reconstruction. In 1989 he visited with Ernst Bauer’s group in Clausthal, Germany, using low energy electron microscopy (LEEM) to image this faceting in real time. In 2000 he joined the Materials Science and Engineering Department, and began studies of directed self-organization during growth and sublimation on semiconductor surfaces, using lithographic patterning. In 2006 he was a visiting professor at the National Nanotechnology Laboratory, in Lecce, Italy. He is the author of more than 100 papers and has given over 40 invited talks on his work in the US, Europe and Japan. He was named the Laboratory for Physical Sciences Faculty Researcher of the year in 2002. In addition to MSE, he has affiliate positions in Physics and ECE, and was a founding member of the UM-MRSEC at the University of Maryland.
He was the founding Coordinator of the Interdisciplinary Minor Program in Nanoscience and Technology. His current research is in the fields of directing self-assembly of nanostructures at the mesoscale, plasmonics, and application of nanotechnology to the conservation of cultural heritage objects.
Present Position: Professor, Department of Materials Science and Engineering, Affiliate Professor, Department of Physics, and Department of Electrical and Computer Engineering University of Maryland, College Park, MD 20742