Interfaces of two immicible polymer thin films studied by X-ray Scattering
Abstract
We investigated the interface of PS/PMMA and PS/ PVP as a function of film thickness by X-ray scattering, SIMS and AFM techniques. Although the neutron scattering of two immiscible polymer/polymer interfaces has been investigated by Sferrazza et.al( PRL, 78, 1997), the disadvantages of small qz range( 0.15A-1) and lower resolution of neutron reflectivity brought difficulties to detect within reasonable error range. By the way X-ray reflectivity can overcome these limitation of neutron reflectivity because of its much larger qz ranges and high resolution, but the small contrast, which is that most of polymers have very similar refractive index of X-ray, was only problem. Recently, we found that X-ray reflectivity can be analyzed using Fourier method (Seeck et al, APL, in preparation) to detect the ultra-small density contrasts in thin film layer system. Therefore with great advantages of X-ray scattering compared to neutron scattering, this method can be applied specially to polymer-polymer interfaces without any further contrast alteration. The results are showing that interfacial energy as well as film thickness are the most important factors to modify the intrinsic interfacial width and additional interfacial broadening by capillary wave. The results were well matched to the theoretical calculation within very small error ranges. Experiments are currently in progress for bilayer systems with diblock copolymer. The existence of diblock copolymer can reduce tremendously the interfacial tension of immcible polymer/polymer interface and bring the interfacial length broadening.
- Publication:
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APS March Meeting Abstracts
- Pub Date:
- March 2000
- Bibcode:
- 2000APS..MARL36081S