CBE Special Seminar: Bernard Lotz (CNRS and Université de Strasbourg)

Abstract

Crystalline polymers morphology: an overview

The organization and structure of polymers is analyzed by various techniques. Global means, such as DSC, are ideal when dealing with e.g. phase transitions (crystallization, melting, glass transition, etc.). Some of these techniques (e.g. IR or NMR) do probe local features and sub-molecular dynamics. Analysis of the crystalline polymers morphology and structure is often more demanding, but it provides unexpected opportunities to explain “visible” features by sub-molecular details that cannot be reached by available techniques. The presentation will illustrate several issues that could be solved by resorting to structural analyses. They are taken from the literature and from my own work. Following a short survey of chain folding and its consequences, of nucleation and growth processes, and of lamellar shape (twist and scroll), the recent analyses of two several decades-long puzzles will be developed: the Brill transition in nylons and the real nature of a minor (but controversial!) component of crystalline polymers, the RAF (Rigid Amorphous Fraction).

Biography

Dr. Bernard Lotz received his MS in physical chemistry from the Université Louis Pasteur in Strasbourg, FR and his PhD from Université Louis Pasteur under the tutelage of Prof. André Kovacs.  He did a two-year postdoc at Bell Labs in Murray Hill, NJ, and then joined the Centre de Recherche sur les Macromolécules in Strasbourg, France, where he built a career addressing the fundamentals of crystallization of macromolecular materials.  He is currently Director of Research (éméritus) at the Institute Charles Sadron in Strasbourg.  His current interests include the elusive Brill transition in nylons and the controversial rigid amorphous phase (RAF) in semicrystalline polymers. He is the recipient of multiple awards, including the “Grand Prix” from the Groupe Français des Polymères for the elucidation of the crystal structure of silk and Fellow of the American Physical Society.  He has over 300 archival publications and over 21,500 citations with an h-index of 81.