IUVSTA 15th International Vacuum Congress (IVC-15), AVS 48th International Symposium (AVS-48), 11th International Conference on Solid Surfaces (ICSS-11)
    Applied Surface Analysis Wednesday Sessions
       Session AS-WeM

Paper AS-WeM7
Synthesis and Characterization of Poly(imidesiloxane) Copolymers Containing Two Siloxane Segment Lengths: Surface Composition and Its Role in Adhesion

Wednesday, October 31, 2001, 10:20 am, Room 134

Session: Biomaterials and Polymers
Presenter: C.M. Mahoney, State University of New York at Buffalo
Authors: C.M. Mahoney, State University of New York at Buffalo
J.C. Rosenfeld, Occidental Chemical Corporation
J.A. Gardella, Jr., State University of New York at Buffalo
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Polyimidesiloxane (SIM) copolymers are extremely important materials for microelectronic applications due to their excellent adhesive properties, low dielectric constants and good overall thermal and mechanical properties. Hence it is of importance to study the surface and interfacial properties of this polymer system. A series of poly(imidesiloxane) (SIM) copolymers have been synthesized, where the total composition of PDMS was maintained at 10% (by weight) with two different PDMS segment lengths of different relative composition. (e.g. 5% PDMS containing 1 repeat unit, designated G-1 and 5% PDMS containing 9 repeat units, designated G-9 incorporated into the same polymer vs. 1% G-1 and 9% G-9 in the same polymer). Two main polymer series were synthesized, one containing G-1 and G-9 in varying ratios, and the other containing G-5 and G-9. Both of these series have been analyzed using angle dependent X-Ray Photoelectron Spectroscopy (XPS). The results suggest that there is preferential segregation of longer siloxane segment lengths to the surface. The angle dependent data was then used to obtain an in-depth profile by using a deconvolution process. From the profiles, it was determined that the thickness of the surface PDMS layer of all polymers containing both G-9 and G-1 were the same for all compositions studied, while that of the pure 10% G-1 was much less. The adhesion strengths of these polymers were measured using peel strength tests and the adhesion values were correlated to the XPS results. It was found that the adhesion of the pure 10% G-1 was much higher than that of any other polymer in the series. The remainder of the polymers in the series all had similar adhesion values. These results are consistent with a model of the surface, which has longer segment lengths preferentially segregating and dominating the adhesive properties.