Reflection Method for Obtaining the Infrared Spectrum of a Thin Layer on a Metal Surface

Greenler, Robert G.

doi:10.1063/1.1671315

Cited by 287 publications

(120 citation statements)

References 9 publications

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“…Reflection on the metal surface results in an electrical field that is strongly elliptically polarized in RAIR measurement. With only a significant contribution of the component perpendicular to the film surface, the intensity of the corresponding band would become obviously stronger in RAIR spectrum than that in TIR spectrum; with a component parallel to the film surface, the intensity of the corresponding band would become weaker [24] . Fig.…”

Section: Reflection-absorption Infrared (Rair)mentioning

confidence: 98%

Structure characterization of melt drawn polyethylene ultrathin films

et al. 2006

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Highly oriented ultrathin polyethylene (PE) films were prepared by a melt-draw technique. Transmission electron microscopy study on the obtained ultrathin films indicates that the melt drawn PE thin films consist of highly oriented edge-on lamellae aligned perpendicular to the drawing direction. Electron diffraction confirms that the PE chains in crystalline phase are highly oriented in film plane along the drawing direction, while only a random orientation of the crystallographic a-and b-axes can be described through electron diffraction. The IR results on the melt-drawn ultrathin PE films demonstrate that the PE molecular chains in both crystalline and amorphous phases of the melt drawn thin films are well oriented along the drawing direction. Moreover, the IR results indicate that in the crystalline phase, the crystallographic b-axis tend to lie in the thin film plane, while in the amorphous phase, the skeleton plane of some local chains prefers to parallel the film plane. The alignment of b-axis of PE crystals in ultrathin films originates from the fact that the b-axis is the fastest growth direction of the PE crystals.The technological significance of the highly oriented polymer materials derives from the fact that the properties of the oriented materials may exceed those of their isotropic species by general orders of magnitude. For example, the stiffness and strength of highly oriented crystalline polymers [1,2] can increase to a factor of 100 compared with their non-oriented counterparts. Therefore, highly oriented polymer materials have received considerable interest in the past few decades. Generally, in most polymer processing operations, such as fiber spinning and extrusion, etc., the molten polymer is exposed to varying levels of flow fields, which encourage the development of high degree of orientation. For these products, wide-and small-angle X-ray scatterings are frequently used for characterizing their morphological information. Moreover, skillful experimental techniques for producing highly oriented ultrathin polymer films, such as drawing from the thin polymer melts [3] and frictions from the solid blocks [4,5] , enable us to produce thin films of tens nanometers, which are ideal for real space morphology as well as electron diffraction studies on themselves, as substrate inducing crystallization of other polymers. Consequently, a large number of investigations have been done to characterize the morphological and orientational features of oriented thin polymer films. It should be pointed out that, however, the information about chain orientation given by electron and X-ray diffractions is only related to the chains in crystalline region of the semicrystalline polymers. To our knowledge, the alignment of the chains in the amorphous areas of the highly oriented thin films is hardly concerned so far.Infrared spectroscopy (IR) is sensitive to both chain conformation and molecular environment. Fourier transform infrared spectroscopy combining with polarized infrared beam is a powerful tool to probe ...

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Section: Reflection-absorption Infrared (Rair)mentioning

confidence: 98%

Structure characterization of melt drawn polyethylene ultrathin films

et al. 2006

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“…Hence, an FT-IR analysis by a reflection absorption (RA) technique (19)(20)(21)(22)(23)(24) was applied to specify the orientations of amino acids adsorbed on the metal surface using SUS 316L stainless steel plates under different conditions. First, a stainless steel plate was placed in contact with amino acid solution for 1 h at 30…”

Section: Ft-ir Analysismentioning

confidence: 99%

Adsorption Behavior of Amino Acids on a Stainless Steel Surface

Imamura

Mimura

Okamoto

et al. 2000

Journal of Colloid and Interface Science

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“…Since the PM-RAIRS is insensitive to the dipole parallel to the metal surface [40,41], the weak intensity of the in-plane B-O-H bending mode supports the preferential orientation of the boric acid crystalline platelets parallel to the substrate, as shown by XRD analysis (Fig. 2).…”

Section: Spectroscopic Investigation Of the Adsorbed Molecules On Bormentioning

confidence: 74%

Origin of Ultra-Low Friction of Boric Acid: Role of Vapor Adsorption

2015

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Boric acid is a lamellar solid lubricant that can give an ultra-low friction coefficient. The origin of this ultra-low friction of boric acid was investigated using tribology and spectroscopy techniques in inert, humid, and organic vapor conditions. It was found that boric acid itself experiences high friction and catastrophic surface wear when rubbed with a stainless steel ball in dry nitrogen or oxygen environments, but it gives very low friction (l = 0.06) in humid and acetone vapor environments. Short-chain alcohol vapors (ethanol and n-pentanol) did not show these ultra-low friction values. Vibrational spectroscopy indicates that the lubricating vapors do not adsorb on the basal plane of the boric acid crystal but likely adsorb onto the edge sites of the lamella. The alcohol molecules impinging from the gas phase readily react with the boric acid to form a high vapor pressure molecule that desorbs from the surface. The ''unlocking'' of the highenergy edge sites by adsorbed acetone and water vapor appears to be needed for the lamella to shear along the basal plane direction.

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Reflection Method for Obtaining the Infrared Spectrum of a Thin Layer on a Metal Surface

Cited by 287 publications

References 9 publications

Structure characterization of melt drawn polyethylene ultrathin films

Structure characterization of melt drawn polyethylene ultrathin films

Adsorption Behavior of Amino Acids on a Stainless Steel Surface

Origin of Ultra-Low Friction of Boric Acid: Role of Vapor Adsorption

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