Download or read book Non Destructive Characterization of Polymer Metal Interphases Using Surface Enhanced Raman Scattering written by F. J. Boerio and published by . This book was released on 1990 with total page 39 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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. (JG).

Download or read book Non Destructive Characterization of Polymer Metal Interfaces Using Surface Enhanced Raman Scattering SERS written by F. J. Boerio and published by . This book was released on 1990 with total page 3 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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. Many models have been proposed to explain SERS, but it is now considered that most of the enhancement is related to two mechanisms. The first is associated with the large electric fields that can be induced at the surfaces of metal particles having small radii of curvature. The second is associated 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 electromagnetic mechanism may extend several monolayers away from the surface. Considering that normal Raman scattering by polymers is weak and that scattering by molecules adjacent to the substrate is strongly enhanced, it is evident that SERS can be used for non-destructive characterization of interfaces between polymer films and metals as long as the films are not so thick that scattering by the bulk of the film is comparable in intensity to SERS from the interface. Keywords: DD Form 1473, Nondestructive characterization, Polymer/Metal interfaces, Surface-enhanced raman scattering, SERS, Adsorption, Silver, Acrylic adhesive system.

Download or read book Non Destructive Characterization of Polymer Interphases and In Situ Polymerization Using Surface Enhanced Raman Scattering written by and published by . This book was released on 1992 with total page 9 pages. Available in PDF, EPUB and Kindle. Book excerpt: The molecular structure of interphases between substrates such as metals and graphite and polymer systems cured against them was determined using surface analysis techniques such as reflection-absorption infrared spectroscopy, X-ray photoelectron spectroscopy, and surface enhanced Raman scattering. It was found that the substrates had a significant effect on the molecular structure of the interphase and that the molecular structure of the interphase was significantly different from that of the bulk polymers. In some cases, there was a vigorous reaction between components of the polymer system and the substrate. Thus, when an acrylic adhesive was cured against silver substrates, o-benzoic sulfimide, a component of the curing system, segregated to the interface and reacted with metal ions to form salts. The salts reacted with a peroxide in the curing system to form radicals which initiated polymerization. In other cases, components of the polymer preferentially adsorbed onto the substrate. Thus the curing agent dicyandiamide was adsorbed at the interface between an epoxy and silver. The behavior of polyamic acids was strongly affected by substrates they were deposited on.

Download or read book Non destructive Characterization of Polyimide silver Interphases Using Surface enhanced Raman Scattering written by Jin-Ter Young and published by . This book was released on 1990 with total page 220 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Characterization of Polymer Interphases Using Surface Enhanced Raman Scattering written by F. J. Boerio and published by . This book was released on 1990 with total page 3 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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. (JG).

Download or read book Characterization of Polymer Surfaces and Interfaces Using Surface enhanced Raman Scattering written by Pel-Pel Hong and published by . This book was released on 1992 with total page 416 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Structure and Properties of Polymer Interphases written by F. James Boerio and published by . This book was released on 1988 with total page 38 pages. Available in PDF, EPUB and Kindle. Book excerpt: The molecular structure of interphases between polymer systems and metal substrates was determined by using x-ray photoelectron spectroscopy (XPS), reflection-absorption infrared spectroscopy (RAIR), and attenuated total-reflection infrared spectroscopy (ATR) to characterize the failure surfaces of double cantilever beam adhesive joints prepared by curing beams of epoxies against metal beams. The structure of the interphases depended strongly on the curing agent, metal substrate, and use of a silane primer on the substrate. When joints were prepared by curing an epoxy with a tertiary amine curing agent at 75 C against a steel substrate primed with a dilute aqueous solution of gamma-aminopropyltriethoxy-silane, there was little reaction between the primer and adhesive and failure occurred near the primer/adhesive interface. The interphase consisted of low molecular weight siloxane oligomers in which the amino groups formed bicarbonates with water and carbon dioxide absorbed from the atmosphere. When similar joints were cured at 150 C, the bicarbonates dissociated, enabling the adhesive and primer to react, and shifting the locus of failure near the primer/adherend interface or into the epoxy. The use of surface-enhanced Raman scattering (sers) for non-destructive characterization of interphases between polymers and metals was demonstrated. (aw).

Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1995 with total page 994 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Characterization of Interfaces Between Polymers and Substrates Using Surface enhanced Raman Scattering written by Wen-Hsien Tsai and published by . This book was released on 1991 with total page 530 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Surface Enhanced Raman Scattering written by and published by . This book was released on 1989 with total page 27 pages. Available in PDF, EPUB and Kindle. Book excerpt: Surface-enhanced Raman scattering (SERS) is a process in which the Raman scattering cross section of molecules adsorbed onto the surfaces of metals such as silver, copper, and gold is increased by as much as six orders of magnitude. However, the enhancement is short-range and is restricted to the first few layers of molecules adjacent to the surface. As a result, SERS can be used to characterize adsorption of organic compounds onto metals and can be used for non-destructive characterization of interfaces between polymer films and metal substrates as long as the polymer films are not so thick that normal Raman scattering from the bulk of the film is more intense than SERS from the interface. SERS spectra were obtained from bilayers prepared by spin-coating thin films of polymers such as polystyrene onto silver island films and then overcoating them with much thicker films of a second polymer such as polystyrene sulfonate. The spectra were characteristic of the films adjacent to the silver and not the overlayers as long as the thickness of the films adjacent to the substrate was more than about 100 A in thickness. SERS spectra obtained from thick films of an acrylic adhesive spin-coated onto silver were identical to normal Raman spectra of salts of saccharin, a component of the cure system, and to SERS spectra of saccharin, indicating that saccharin segregated to the adhesive/substrate interface and adsorbed onto the substrate by dissociation. (aw).

Download or read book Characterization of Metal and Polymer Surfaces V2 written by Lieng-Huang Lee and published by Elsevier. This book was released on 2012-12-02 with total page 482 pages. Available in PDF, EPUB and Kindle. Book excerpt: Characterization of Metal and Polymer Surfaces, Volume 2: Polymer Surfaces presents the proceedings of the Symposium on Advances in Characterization of Metal and Polymer Surfaces, held in New York, on April 5–8, 1976. This book provides information pertinent to surface science and discusses the applications of surface analyses to polymer technology. Organized into four parts encompassing 21 chapters, this volume starts with an overview of the measurement of binding energies and chemical shifts, which remain a relevant aspect of electron microscopy for organic and inorganic compounds. This text then explores the capability of electron spectroscopy for chemical analysis (ESCA) as a spectroscopic tool that enables the features of structure and bonding in surface, subsurface, and bulk regions of polymer systems to be elaborated. Other chapters consider the surface and interfacial properties of polymers, which are significant in various biomedical applications. This book is a valuable resource for analytical and polymer chemists.

Download or read book Government Reports Annual Index written by and published by . This book was released on 1990 with total page 1120 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Surface Enhanced Raman Scattering from Model Acrylic Adhesive Systems written by and published by . This book was released on 1989 with total page 34 pages. Available in PDF, EPUB and Kindle. Book excerpt: Surface-enhanced Raman scattering (SERS) has been observed from a model acrylic adhesive deposited onto silver island films. SERS spectra of the adhesive system were very similar to SERS spectra of o-benzoic sulphimide (saccharin), a component of the curing system of the adhesive, and to normal Raman spectra of the sodium salt of saccharin. When saccharin was replaced in the curing system by benzoic acid, SERS spectra of the adhesive were similar to SERS spectra of benzoic acid and to normal Raman spectra of benzoic acid salts. The intensity of the SERS spectra was independent of the thickness of the adhesive films, indicating that the observed Raman signal was characteristic of the interface and not of the bulk of the films. These results demonstrate that saccharin and benzoic acid wee preferentially adsorbed at the silver surface to form metal salts and that surface-enhanced Raman scattering can be used for non- destructive characterization of interphases between polymer films and SERS- active metal substrates as long as the films are not so thick that normal Raman scattering from the bulk is comparable in intensity to the SERS from the interphase.

Download or read book Characterization of Model Polyimide Silver Interphases Using Surface Enhanced Raman Scattering written by W. H. Tsai and published by . This book was released on 1990 with total page 48 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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. (JG).

Download or read book Government Reports Announcements Index written by and published by . This book was released on 1992 with total page 684 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Physics Briefs written by and published by . This book was released on 1994 with total page 934 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Science of Composite Interfaces written by R. G. Brandt and published by Elsevier Science & Technology. This book was released on 1990 with total page 334 pages. Available in PDF, EPUB and Kindle. Book excerpt: