1. Direct experimental evidences of the density variation of ultrathin polymer films with thickness
- Author
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Nicolas Delorme, Soumaya Ben Jabrallah, Joanna Giermanska, Jean-Paul Chapel, Guillaume Vignaud, Centre de Recherche Paul Pascal (CRPP), Université de Bordeaux (UB)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Institut de Recherche Dupuy de Lôme (IRDL), Université de Bretagne Sud (UBS)-Université de Brest (UBO)-École Nationale Supérieure de Techniques Avancées Bretagne (ENSTA Bretagne)-Centre National de la Recherche Scientifique (CNRS), Institut des Molécules et Matériaux du Mans (IMMM), Le Mans Université (UM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), ANR-18-CE06-0016,SISAL,Auto-Assemblage de bicouches de copolymères amphiphiles induit par une surface(2018), Teulet, Nadine, and APPEL À PROJETS GÉNÉRIQUE 2018 - Auto-Assemblage de bicouches de copolymères amphiphiles induit par une surface - - SISAL2018 - ANR-18-CE06-0016 - AAPG2018 - VALID
- Subjects
chemistry.chemical_classification ,[CHIM.POLY] Chemical Sciences/Polymers ,Materials science ,Polymers and Plastics ,Organic Chemistry ,02 engineering and technology ,Quartz crystal microbalance ,Polymer ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Thermal expansion ,0104 chemical sciences ,Condensed Matter::Soft Condensed Matter ,chemistry.chemical_compound ,[CHIM.POLY]Chemical Sciences/Polymers ,chemistry ,Volume (thermodynamics) ,Materials Chemistry ,Polystyrene ,Composite material ,Thin film ,0210 nano-technology ,Glass transition ,Dissolution - Abstract
International audience; Beyond the peculiar glass transition temperature (Tg) studied extensively for over two decades, we have investigated in this work the variation of the mass density of polymer thin films, a key property barely put forward in the literature. We were able to directly measure the mass density of polystyrene (PS) and poly (methyl methacrylate) (PMMA) thin films as a function of their thickness from accurate Quartz Crystal Microbalance (QCM) dissolution experiments. Depending on the chemical nature of the polymers, the results showed an unambiguous variation of the mass density when the film thickness was reduced: an increase for PS and a decrease for PMMA films. In the last part, we measured the coefficient of thermal expansion (CTE) of both polymers to rationalize the apparent inconsistency of an increase/decrease in the mass density with the commonly observed depression/rise of the Tg of PS/PMMA films. Surprisingly, the coefficient of thermal expansion and the mass density showed a similar variation with thickness, pointing out a clear correlation between the glass transition temperature, the coefficient of thermal expansion and the free volume of the polymer.
- Published
- 2021
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