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The molecular structure of interfaces formed by curing the polyamic acid of pyromellitic dianhydride (PMDA) and oxydianiline (ODA) against copper and gold substrates was determined using surface-enhanced Raman scattering (SERS) and reflection-absorption infrared spectroscopy (RAIR). It was found that acid groups of the polyamic acid reacted with metal ions on the substrates to form carboxylate salts when the polyamic acid was spin coated onto metal substrates. Formation of carboxylates on the copper surface extended several hundred angstroms into the polyamic acid films, while only trace levels of carboxylates were formed on the gold surface. Formation of carboxylate salts suppressed the curing of polyamic acid on copper substrates. However, the degree of curing of the polyamic acid was high on gold surfaces. These results were compared to our previous work concerned with the molecular structure of interfaces between PMDA/ODA.

Surface-enhanced Raman scattering (SERS) was used for the non- destructive characterization of interphases between epoxy/anhydride adhesive systems and silver substrates. Normal Raman spectra of benzophenone tetra- carboxylic dianhydride (BTDA) were characterized by strong bands near 1785 and 1860 1/cm that were assigned to the anhydride groups, a strong band near 1690 1/ cm that was assigned to the benzophenone C=O stretching mode, and by a strong band near 1620 1/cm that was attributed to vibration and to the benzophenone C=O stretching mode were prominent in the SERS spectra of BTDA but the bands related to the anhydride group were missing, indicating that the anhydride groups were hydrolyzed at the silver surface to form carboxylate groups. (JG)

Surface enhanced Raman scattering (SERS) is an analytical technique in which the Raman scattering cross sections of molecules adsorbed onto the roughened surfaces of certain metals are enhanced by as much as six orders of magnitude compared to their value for normal Raman scattering. The mechanisms are associated with the large electric fields that can be induced at the surfaces of metal particles having small radii of curvature and with formation of charge transfer complexes between the adsorbed molecules and the substrate. Enhancement due to the charge transfer mechanism is obtained only for molecules immediately adjacent to the surface but enhancement due to the electromagnetic mechanism may extend several monolayers away from the surface. Since normal Raman scattering by polymers is weak and scattering by molecules adjacent to the substrate is strongly enhanced, SERS can be used for nondestructive characterization of interfaces between polymer films and metals. Silver, Polymers, Materials, Acrylic monomer, Cumene, Hydroperoxide(CHP), Acetylphenylhydrazine(APH), Saccharin, Adhesives, Pyromellitic diimide (PMDI), Surface properties.

Surface-enhanced Raman scattering (SERS) was used to investigate the adsorption of model compounds for polymides onto silver island films and onto highly oriented pyrolytic graphite (HOPG). SERS spectra of pyromellitic diimide (PMDI) adsorbed onto silver island films were mostly independent of the thickness of the PMDI films, confirming the SERS is an interfacial rather than bulk effect and that SERS can be used to examine the interface between an adsorbed film and a metal substrate without interference from normal Raman scattering by the bulk of the film. Differences in the relative intensities of several bands in the normal Raman and SERS spectra of PMDI adsorbed onto silver island films were related to orientation effects. It was concluded that most molecules were physisorbed with a vertical configuration in which the plane of the molecules was perpendicular to the surface and one imide group was adjacent to the surface. Keywords: Phthalimide(PIMH), Molecule structures, Organic chemistry, Adsorption, Surface properties.

Surface-enhanced Raman scattering (SERS) and reflection-absorption infrared spectroscopy (RAIR) were used to determine the molecular structure of interphases between polymers and metal substrates. An interesting example was provided by pyromellitic diimide (PMDI), a model compound for polyimides, and silver substrates. Normal Raman spectra of PMDI were characterized by strong bands near 1772, 1370, 760, and 655 1/cm and medium intensity bands near 1630 and 1205 1/cm were weak in SERS spectra obtained from films of PMDI spin-coated onto silver island films while those near 1370 and 1205 1/cm and a new band near 685 1/cm were strongest. Differences between the normal Raman and SERS spectra were related to orientation effects indicating that PMDI was absorbed onto silver with a vertical conformation in which the rings were perpendicular to the surface and one imide group was in contact with the surface. Keywords: Polymer interphases, Surface enhanced raman scattering, Molecular structures, Thin films, RAIR, SERS, DD Form 1473, Spectroscopy.

Reliability, redundancy, and survivability are key issues as integrated requirements for flight control, fire control, propulsion control and navigation are developed. These integrated systems require dependable sources of inertial measurement data. Current inertial systems, however, are expensive to acquire and maintain, dedicated to specific systems, and are not designed to meet integrated reliability, redundancy, and survivability, requirements. The Multifunction Strapdown Inertial System concept uses a minimum number of inertial sensors in a survivable configuration to provide inertial data for flight control, navigation, weapon delivery, cockpit displays, and sensor stabilization. Because of advantages in survivability, life cycle cost, maintainability and performance, the Multifunction Flight Control Reference System (MFCRS) program was initiated to verify, through flight test, on a McDonnel Douglas F-15 Eagle the key issues of redundancy management and flight control. A redundancy management system based on parity equations was designed. The sensors were arranged in two skewed and dispersed clusters. (Author), This article is from Advances in Strapdown Inertial Systems, Lecture Series Held in Athens, Greece on 14-15 May 84, in Rome, Italy on 17-18 May 84, in Copenhagen, Denmark on 21-22 May 84, AD-A143 244, p8-1 - 8-20.

Reliability, redundancy, and survivability are key issues as integrated requirements for flight control, fire control, and propulsion control are developed. These integrated control systems require dependable sources of inertial measurement data. Current inertial sensors, however, are expensive to acquire and maintain, dedicated to specific systems, and are not designed to meet integrated control reliability, redundancy, and survivability requirements. The concept uses a minimum number of inertial sensors in a survivable configuration to provide inertial data for flight control, navigation, weapon delivery, cockpit displays, and sensor stabilization. Because of advantages in survivability, life cycle cost, size, and performance, the MFCRS program was initiated to verify, through flight test, the key issues of redundancy management and flight control. A key lesson learned is that integration of inertial data for fire control, flight control, and propulsion control will require close coupling and coordination between functional groups to resolve performance conflicts and compromises. Testing to data has not shown any basic flaws in the multifunction concept., This article is from 'Integration of Fire Control, Flight Control and Propulsion Control Systems Conference Proceedings,' AD-A135 166, p12-1--p12-10.