High-Resolution Profiling of the Polyimide−Polyimide Interface

• Published in: Macromolecules 1996-10, Vol.29 (21), p.6880-6891
• Main Authors: Stoffel, Nancy C, Dai, Chi-An, Kramer, Edward J, Russell, Thomas P, Deline, Vaughn, Volksen, Willi, Wu, Wen-li, Satija, Sushil
• Format: Article
• Language: English
• Subjects: Applied sciences; Exact sciences and technology; Organic polymers; Physicochemistry of polymers; Properties and characterization; Surface properties
• ISSN: 0024-9297; 1520-5835
• DOI: 10.1021/ma9601880

Dynamic secondary ion mass spectrometry (SIMS), nuclear reaction analysis, and neutron reflectometry were used to profile polyimide−polyimide interfaces. For interfaces between two layers of poly(4,4‘-oxydiphenylene−pyromellitimide) (PMDA−ODA) polyimide it was determined that the interfacial fracture energy G c and the interfacial width depended primarily upon the imide fraction, f, of the base layer. For f 0.9. The PMDA−ODA/PMDA−ODA interface formed with a fully imidized base layer was ∼30 Å in width, whereas that formed when f = 0.9 was ∼80 Å in width. The interface formed during the spin-casting process did not broaden significantly after annealing at 400 °C. We also investigated the interface between a more flexible thermoplastic polyimide poly(4,4‘-oxydiphenylene−oxydiphthalimide) (ODPA−ODA) and a fully imidized PMDA−ODA layer. The shape of the ODPA−ODA/PMDA−ODA interface was found to depend upon annealing temperature. Unannealed samples and samples annealed at 350 °C could be fit with an error function, and the interfacial width was ∼50 Å. Samples annealed at 400 and 450 °C were best fit by a fairly sharp interfacial profile with ODPA−ODA tails proceeding into the PMDA−ODA layer. The volume fraction of the ODPA−ODA in the PMDA−ODA depended upon the annealing temperature T ann. The G c of the ODPA−ODA/PMDA−ODA interface appears limited by the solubility of ODPA−ODA in PMDA−ODA.