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Transient Interfacial Instability in Bilayer Polymer Films As Observed by Neutron Reflectivity Studies



M Hayashia, TT Hashimoto, M J. Weber, H Grull, A R. Esker, Charles C. Han, Sushil K. Satija


We investigated fundamental processes involved in reactive blending of a system composed of polyamide (PA) and deuterated polysulfone having a reactive end group(R ) (dPSU-R) diluted with a low molecular mass polysulfone (low-PSU) by neutron reflectivity (NR). For this purpose we prepared bilayer films composed of a film of a uniform mixture of dPSU-R/low-PSU and a film of PA. We found an intriguing phenomenon associated with the transient instability of interface between the PA layer and the DPSU-R/low-PSU layer during annealing at high temperatures for chemical reaction between dPSU-R end-group and amine end groups of PA. The transient interface instability, as observed by a transient disappearance of the reflectivity fringes followed by a subsequent recovery of the fringes during annealing at the reaction temperatures, was found to be caused by a transient interdiffusion of a small molecular mass fraction of low-PSU into the PA layer and to be coupled with the Kerkendall effect, a shift of the average position of the interface due to the interdiffusion. Thus the special Kerkendall effect observed here was accompanied by the transient interface instability.
No. 24


interdiffusion, Neutron reflectivity, polyamide, polysulfone, reactive blending, transient interface instability


Hayashia, M. , Hashimoto, T. , Weber, M. , Grull, H. , Esker, A. , Han, C. and Satija, S. (2001), Transient Interfacial Instability in Bilayer Polymer Films As Observed by Neutron Reflectivity Studies, Macromolecules, [online], (Accessed July 19, 2024)


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Created October 31, 2001, Updated October 12, 2021