The presence of leachable alkali ions, or their hydrated sites in the glass, is believed to be a determining factor for the interfacial water structure at the glass surface, influencing the surface properties of glass. The interfacial water structure on soda‐lime silicate glass in humid ambience at room temperature was analyzed with sum‐frequency‐generation (SFG) vibration spectroscopy, which can probe the interfacial water layer without spectral interferences from the gas phase water. The soda‐lime glass surface exposed to water vapor shows three sharp SFG peaks at 3200, 3430, and 3670 cm−1 in SFG, which is drastically different from the SFG spectra of the water layers on the fused quartz glass surface and the liquid water/air interface. The sharp peak at 3200 cm−1 is believed to be associated with the hydronium ions in the Na+‐leached silicate glass surface. The 3200 cm−1 peak intensity varies with the relative humidity, indicating its equilibrium with the gas phase water. It is proposed that the hydronium ions in the Na+‐leached sites produce compressive stress in the silicate glass surface; thus the growth of hydronium ions with increasing humidity might be responsible for the increased wear resistance of soda‐lime glass surfaces in near‐saturation humidity conditions.

The friction behavior of diamond-like carbon (DLC) is very sensitive to the test environment. For hydrogen-rich DLC tested in dry argon and hydrogen, there was always an induction period, so-called "run-in" period, during which the friction coefficient was high and gradually decreased before DLC showed an ultralow friction coefficient (less than 0.01) behavior. Regardless of friction coefficients and hydrogen contents, small amounts of wear were observed in dry argon, hydrogen, oxygen, and humid argon environments. Surprisingly, there were no wear or rubbing scar on DLC surfaces tested in n-pentanol vapor conditions, although the friction coefficient was relatively high among the five test environments. Ex situ X-ray photoelectron and near-edge X-ray absorption fine-structure spectroscopy analyses failed to reveal any differences in chemical composition attributable to the environment dependence of DLC friction and wear. The failure of getting chemical information of oxygenated surface species from the ex situ analysis was found to be due to facile oxidation of the DLC surface upon exposure to air. The removal or wear of this surface oxide layer is responsible for the run-in behavior of DLC. It was discovered that the alcohol vapor can also prevent the oxidized DLC surface from wear in humid air conditions.

The boundary film formation and lubrication effects of low molecular weight silicone lubricant molecules with cationic side groups were studied. Poly(N,N,N-trimethylamine-3-propylmethylsiloxane-co-dimethylsiloxane) iodide was synthesized and deposited on silicon oxide surfaces to form a bound-and-mobile lubricant film. The bound nature was investigated with ellipsometry, water contact angle, and X-ray photoelectron spectroscopy for the polymers with cationic mole percent of 6, 15, and 30 mol % (monomer based). The bound layer thickness decreased as the cationic content increased. The quaternary ammonium cations in this layer were electrostatically bound to the substrate surface. The mobile nature of the multilayers was explored with scanning polarization force microscopy. The multilayer films exhibited characteristic topographic features due to ionic interactions within the polymer film. Contact scratching of these films altered the multilayer topography within the contact scanned area. Even after high load contact scanning, the bound layer was not removed from the scanned region. These results implied that the molecules in the first layer are strongly bound and the molecules in the multilayers are mobile. Both nanoscale and macroscale tribological tests of these films revealed that the polymer with 15 mol % cationic groups gives lower friction and adhesion than the 6 and 30 mol % cationic polymers as well as the polydimethylsiloxane control sample. This seems to be due to a synergistic effect between the bound and the mobile layers.

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The substrate protection and self-healing capability of a cationic polymer lubricant (CPL) on a silicon oxide surface were tested with a pin-on-disc tribometer and atomic force microscopy (AFM). CPL was made of low molecular weight polydimethylsiloxane (PDMS) containing covalently attached quaternary ammonium cations and iodide counter-anions. CPL was spin-coated on the silicon oxide surface to form a 3-4 nm thick boundand-mobile lubricant layer. The CPL film capable of binding to the SiO 2 surface through ionic interactions is superior in substrate protection than the neutral PDMS film which cannot form the bound layer. The mobile component in the CPL film readily flows into the lubricant-depleted sliding contact region from the surrounding film. The selfhealing capability of CPL via lateral flow is slightly enhanced in humid environments due to water uptake in the film. The 3-4 nm thick CPL film on silicon oxide takes 30-40 s to flow into a *50 lm wide track, which corresponds to an apparent spreading rate of 2-3 9 10 -11 m 2 /s.

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A simple and efficient way of synthesizing conducting polymers on polymer templates and subsequently improving the connectivity between fibers and hence improving the electrical conductivity of nonwoven porous conducting polymer nanofiber mats is reported. The poly(3,4-ethylenedioxythiophene) (PEDOT) conducting polymer was grown via a vapor-phase polymerization on a nonwoven porous mat of polystyrene (PS) nanofibers containing ferric p-toluenesulfonate (Fe-TS). The PS/Fe-TS nanofibers of diameter ∼300 nm were electrospun and exposed to 3,4-ethylenedioxythiophene (EDOT) vapors. Two different vapor exposure conditions were studied. The shape of the PS template fibers is preserved best under the vapor exposure condition where the EDOT vapor does not condense on the fiber surface. A better electrical conductivity of the fiber mat can be obtained by condensing the EDOT vapor on the PS template fiber during the polymerization. This allows melt-welding of the fibers, which results in a better connectivity between the fibers. The porous PS-PDEOT fiber mats produced under the melt-welding condition showed a sheet conductivity of ∼1 S/cm.

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