A series of electronically conductive nanocomposite materials that consisted of soluble polypyrrole (PPY) and layered montmorillonite (MMT) clay platelets were prepared by effectively dispersing the inorganic nanolayers of MMT clay in organic PPY matrix via an in situ oxidative polymerization with dodecylbenzene sulfonic acid (DBSA) as dopant. Organic pyrrole monomers were first intercalated into the interlayer regions of organophilic clay hosts and followed by a one-step oxidative polymerization. The as-synthesized electronically conductive polypyrroleclay nanocomposite (PCN) materials were then characterized by Fourier transformation infrared (FTIR) spectroscopy, wide-angle powder X-ray diffraction (XRD), and transmission electron microscopy (TEM). PCNs in the form of coatings with low clay loading (e.g., 1.0 wt %) on cold-rolled steel (CRS) were found to exhibit much better in corrosion protection over those of pristine PPY based on a series of electrochemical measurements including corrosion potential, polarization resistance, and corrosion current in 5 wt % aqueous NaCl electrolyte. Effects of the material composition on the thermal stability, optical properties, and electrical conductivity of pristine PPY along with PCN materials, in the form of fine powder, powder-pressed pellet, and solution, were also studied by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), UV-visible absorption spectra, and four-point probe technique, respectively. The viscosity of PPY existed in PCN materials and pristine PPY were determined by viscometric analysis with m-cresol as solvent. The heterogeneous nucleating effect of MMT clay platelets in PPY matrix was studied by wideangle powder XRD. The corresponding morphological images of the nucleating behavior of clay platelets in PPY matrix were investigated by scanning electron microscopy (SEM).

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The surface and perfluoropo~yether (PFPE) lubricantlove~coat pro erties of magnetic hard disks after corrosion stressed at a te~perature Of ' ?' O relative humidity are studied by time-of-flight secondary ion mass spectrometry. The corrosion stress leads to selective migration of cobalt from the magnetic layer which is dependent on disk overcoa~ composition and structure. The corrosion also results in ~vapor~tion and degradation of the P P E lubricant.

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A methodology for quantitative measurement of nitrogen and hydrogen atomic composition of thin carbon nitride film using time-of-flight secondary-ion-mass spectrometry is demonstrated. The nitrogen and hydrogen compositions of the film are determined by the selected ion fragment intensity ratios ICN−/IC2− and IC2H−/IC2− measured in the negative-ion-mass spectrum of the film, respectively. Absolute values for hydrogen and nitrogen atomic compositions are extracted by calibration with nuclear reaction analysis and hydrogen forward scattering methods. The measured ion fragment mass intensities were also used to characterize the structure of the carbon nitride films. The results are compared with those measured from x-ray photoemission spectroscopy.