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Electron emission (EE) from real metal surfaces occurring during sliding contact with a polytetrafluoroethylene (PTFE) rider has been investigated using the thermodynamic data of metal oxides and the X-ray photoelectron spectroscopy (XPS) intensity ratio of oxygen/metal on the surfaces. EE was termed triboelectron emission (TriboEE). Rolled metal sheets of 18 types were used. The metal‒oxygen bond energy calculated from the heat of the formation of metal oxide, (D(M&ndash, O)), was shown to be a key factor in dividing the EE into two routes, the so-called Schottky effect and the tunnel effect, due to the surface oxide layer. The metals in periodic groups 4 (Ti and Zr), 5 (V, Nb, and Ta), and 6 (Mo and W) maintained higher values of D(M&ndash, O), while, moving down the groups, the TriboEE intensity increased, being ascribed to the former route. In groups 10 (Ni, Pd, and Pt) and 11 (Cu, Ag, and Au), the D(M&ndash, O) values decreased moving down the groups, but the TriboEE intensity increased significantly, which can be attributed to the latter route. Furthermore, with the increase in the electrical conductivity of metals, the TriboEE intensity became remarkably high, while the D(M&ndash, O) value fell rapidly and became almost constant. The XPS results showed that the dependence of the D(M&ndash, O) and XPS metal core intensity on the O1s intensity and the XPS intensity ratio of the O1s/metal core was different between groups 10 and 11 and groups 4, 5, and 6. It was concluded that, under the electric field caused on the real metal surface by the friction with PTFE, the electron from metals with small D(M&ndash, O) values predominantly tunnels the surface oxide layer as a surface barrier, while with large D(M&ndash, O) values, the electron passes over the top of the barrier.

In our previous papers, two types of dependence of photoelectron emission from real iron surfaces on the temperature and on the wavelength of the irradiating light at normal atmospheric pressure have been reported (Momose et al. in Appl Phys A 117:1525, 2014; 118:637, 2015). The first article reported experimental curves of the intensity versus temperatures in the 298–626 K range under light irradiation with wavelengths of 200, 210, 220, and 230 nm, called as thermally assisted photoelectron emission (TAPE) (Momose et al. 2014), whereas the second article reported experimental curves of the TAPE intensity versus wavelength for irradiating light in the 300–170 nm range at 298, 381, 425, 476, 527, 576, or 626 K (Momose et al. 2015). In the present paper, these two results were simultaneously discussed based on the Fowler–DuBridge (FD) theory, where the intensity of photoelectron emission is described by the two parameters of the work function, ϕ, and a probability factor, αA. It was concluded from the dependence on wavelength (Momose et al. 2015) of the TAPE intensity that the ϕ value and the αA value were represented by a saturation function and a linear function, respectively, with respect to temperature. However, the FD theory using the temperature dependence of ϕ and αA could not yield that of the TAPE intensity (Momose et al. 2014). To resolve the discrepancy between the two kinds of the TAPE measurements, a curve-fitting method is constructed based on the following three assumptions: two types of the photoelectrons are present, namely hot electrons and thermalized electrons; the former are involved in a thermal desorption process of adsorbates and the latter need a thermal activation energy to escape to vacuum; and thermally stimulated exoelectrons are included in the TAPE phenomenon. The results of applying the method to the TAPE glow curves (Momose et al. 2014) concluded that the release of hot electrons into vacuum was suppressed by the adsorbed H2O on the real iron surface and the desorption energy of the adsorbed H2O was 0.43 eV for 200 nm and 0.48 eV for 210 nm light irradiation. It was further confirmed that the activation energy which the thermalized electrons need to escape to vacuum was 0.20 and 0.13 eV for 200 and 210 nm, respectively. The relationship between this activation energy and the wavelength of the irradiated light is consistent with the results of Momose et al. (2014).

The influence of temperature and surface overlayer on the photoelectron emission from scratched real iron surfaces was investigated using thermally assisted photoelectron emission (TAPE) and X-ray photoelectron spectroscopy (XPS) measurements. The scratching was conducted with a diamond cutter in seven atmospheres. The intensity of TAPE as a function of temperature, called glow curve, was measured in the range 25–339 °C using a Geiger counter under ultraviolet irradiation at 210 nm. The temperature was scanned in two cycles (Up1 and Down1, and Up2 and Down2). The XPS measurements were carried out at 25 °C and after TAPE measurements at 200 and 339 °C. The photoelectron emission intensity at 40 °C in the Up1 scan increased in the order of air

We report the photoemission from real iron surfaces at elevated temperatures, called thermally assisted photoemission (TAPE), and its relationship to the X-ray photoelectron spectroscopy (XPS) results. TAPE measurements were carried out using a Geiger counter under a gaseous atmosphere of He containing 1 % isobutane vapor at normal atmospheric pressure. A sample was initially heated to temperatures ranging from 25 to 353 °C under light irradiation at a certain wavelength of 200, 210, 220, and 230 nm, and then, wavelength was scanned from 300 to 170 nm at the final temperature. The values of a constant related to electron photoemission probability, αA, where A is identical with the Richardson constant, and photothreshold (photoelectric work function), ϕ, were obtained from a plot of the square root of the electron photoemission intensity against the photon energy; the αA values increased with temperature, and the ϕ values also increased with temperature. From the Arrhenius plot, the αA was found to have an activation energy ΔE αA = 0.096 eV. The activation energies of the surface oxygen component ratio Z = O2−/(OH + O2−) and the surface elemental composition ratio X = Fe/(O + N + C + Fe) obtained from the XPS data were also determined from their Arrhenius plots: ΔE Z = 0.113 eV and ΔE X = 0.039 eV, respectively. From a close resemblance between the latter activation energies and those of the ΔE αA and the ΔE a = 0.112–0.040 eV for the quantum yields (Momose et al. in Appl Phys A. doi: 10.1007/s00339-014-8589-7 , 2014), it was found that the increase in the intensity of the TAPE with temperature was strongly associated with the increase in the values of Z and X with temperature. It was therefore concluded that the ability of the surface overlayer to pass the incident light became a rate-determining step to start the photoemission, which was decisively controlled by the temperature-dependent surface oxygen components and surface compositions. The intensity of the TAPE was found to be more predominately influenced by the temperature dependence of the αA than that of the ϕ.

The influence of temperature and incident photon energy on the photoemission quantum yield, Y s, of real iron surfaces has been investigated by thermally assisted photoemission (TAPE). Measurements were carried out using a Geiger counter under a gaseous atmosphere of He containing 1 % isobutane vapor at normal atmospheric pressure in the temperature range 25–353 °C under UV irradiation with wavelengths of 200, 210, 220, and 230 nm. The Y s obtained under irradiation at a given wavelength was found to increase with temperature, particularly more rapidly with wavelengths of greater photon energy. From the Arrhenius plots, the Y s values were found to have activation energies of 0.112–0.040 eV, depending on the photon energy. The chemical composition of the surfaces after TAPE measurements at different temperatures was examined by X-ray photoelectron spectroscopy (XPS). The intensity of species thermally removed from the surface was also measured by temperature desorption spectroscopy (TDS). XPS and TDS results showed the removal of the surface water and weakly bound carbon material from the surface with temperature. It was concluded that the removal of these species with increasing temperature enabled the incident light to penetrate through the surface into the metal, causing the increase in the Y s. The dependence of the activation energies on the photon energy was explained by the change of UV light absorption spectra of the surface water, and the enhancement of the Y s with temperature was also attributed to the influence of iron cations (Fe3+) corresponding to positive holes produced in the surface oxide layer by UV light.

The mechanism of the triboelectron emission (TriboEE) occurring in sliding contact between metals and polytetrafluoroethylene (PTFE) has been investigated. The mapping of the TriboEE intensity for 16 kinds of metals onto the periodic table revealed that the order of the TriboEE intensity between two adjoining metals in the same period was well correlated with that of the work function and photoelectric threshold of metal samples and with that of the surface potential of metal samples and mated PTFE riders after the TriboEE measurement. The relationship of TriboEE intensity to the electronegativity, the ionization energy, and the electron affinity of the elements and the electrical conductivity of metals was also examined.

We report the triboelectron emission (TriboEE) behaviors for copper surfaces in sliding contact with polytetrafluoroethylene and polyimide in relation to the XPS analysis. The TriboEE was measured using a gas-flow Geiger counter. The metal surfaces were subjected to the pretreatments of acetone cleaning, mechanical scratching and oxidizing. It was found that there is interdependence between the TriboEE intensity and the XPS elemental intensity. The formation of empty trapping sites on the polymer surface during the sliding process, which can accept the electrons transferred from the metal substrate, is shown to be a substantial process for the TriboEE to retain.

The effect of ion implantation on the photoemission spectral yield for native oxide-covered Si(100) wafer surfaces has been studied. Three types of H, Si and Ar atoms were employed for the ion implantation. For one sample the yield curve was measured successively first at 25 °C, next after heating to 340 °C, and subsequently after cooling to 40 °C. All implanted samples showed the photoemission in the spectral yield with a much enhanced intensity compared to a nonimplanted sample, moreover, more strongly at 340 °C than at 25 and 40 °C. The analysis of the yield curve showed two distinct photothresholds of φ 1 and φ 2 , which can be attributed to the interface states at the SiO 2 /Si interface and the silicon bulk, respectively, and the creation of a localized emitting center ascribed to E' center (≡Si·). Both thresholds for the implanted samples were reduced about 0.3-0.5 eV compared to those for the nonimplanted sample. The localized center appeared at the photon energy of 5.66 eV (25 and 40 °C) and 5.76 eV (340 °C), and the amount of the centers created at 340 °C was much greater than that at 25 and 40 °C. Interestingly, the amount of the E' centers at 25 °C for the H implanted sample tended to decrease with an increase in the concentration of implanted H atoms.

The characteristics of tribostimulated electron emission (called TriboEE) have been studied for real metal surfaces subjected to rubbing with polytetrafluoroethylene (PTFE). A gas-flow Geiger counter with a counter gas called Q gas was used for observing the TriboEE. Metal samples used were as follows: Ti, Zr (group 4 in the periodic table); V, Nb, Ta (group 5); Mo, W (group 6); Fe (group 8); Co (group 9); Ni, Pd, Pt (group 10); Cu, Ag, Au (group 11); Zn (group 12); Al (group 13); and Sn (group 14). For metals in the same groups of 4, 5, 6, 10, and 11 the number of electrons ejected during rubbing time (called TriboEE total count) increased with an increase in the period for the metal. For the metals in the groups of 4, 10, and 11 the surface fluorine content originating from PTFE debris attached at the surfaces increased with an increase in the period for the metal. The TriboEE total count was almost independent of the photoelectric thresholds determined in photoemission (PE) experiment throughout the metals, while the amount of ejected electrons in the PE measurement tended to decrease with increasing threshold. The surface potential (SP) was almost unchanged before and after the TriboEE measurement. Based on the relation to XPS, PE, and SP results the TriboEE was explained as being associated with the release of electrons transported to the attached PTFE debris from the metal substrate by a surface electric field.

The influence of surface states on photoelectron emission phenomena was investigated to determine the work function precisely. A new method for analyzing the yield spectra of photoelectron emission as a function of temperature has been developed. This method was used to decide the work function and surface state of aluminum metal sheets mechanically scratched and ultrasonically cleaned in organic solvent. The yield spectrum as a function of photon energy exhibited a greatly changed shape with an increase and subsequent decrease in temperature in flowing Q gas under the irradiation of 220 nm wavelength light. The ionization energy of a surface state generated at the surface by the influence of temperature and light was estimated. [DOI: 10.1380/ejssnt.2005.179]

A new surface analysis method using tribostimulated electron emission (called TriboEE) has been developed to estimate the ability for metals in practical use to emit electrons. This method uses an exoelectron emission phenomenon observed only while metal surfaces are mechanically rubbed with a polytetrafluoroethylene (PTFE) rotator. The number of electrons emitted from copper and iron metals during rubbing was measured using a newly hand-made electron counting device, and its relationship to the XPS results of the metal surfaces was investigated. The metal surfaces were prepared as follows: ultrasonic cleaning in acetone (sample I), abrasion with an emery paper (II), and oxidation by heating in air (III). The number of emitted electrons depended strongly on the preparations, resulting in the order I II < III for copper and II « I III for iron. The number of emitted electrons for each surface preparation tended to increase with an increase in the surface composition of fluorine of PTFE debris attached to the surface. The adsorption amount of the fluorine for sample III was much greater than that for samples I and II.

The selectivity of H 2 , CO, CH 4 and C 2 H 4 produced during the electrolysis of CO 2 in aqueous solution at copper electrodes has been investigated in relation to surface analysis of the electrodes after electrolysis by XPS and temperature-programmed photoelectron emission (TPPE) and surface potential (SP) measurements. The electrodes were prepared as follows: (A) only ultrasonic cleaning in acetone; (B) oxidation in air; (C) exposure to argon plasma. The electrolysis time was 3 h at a given potential. With electrode A, on increasing the potential in a negative direction the amount of CH 4 increased, accompanied by a decrease in the amounts of H 2 and CO, and the SP value was positive and shifted in a more positive direction, the TPPE activity increased and in the O1s XPS spectra a peak assigned to adsorbed oxygen developed. The amount of C 2 H 4 was greater in the potential range where both metallic Cu and Cu 2 O existed. With electrode B, the main product was H 2 , the SP value was negative, the TPPE activity was much smaller and Cu 2 O existed more preferentially than metallic Cu. With electrode C, the surface underwent oxidation easily when immersed in solution. With increasing plasma treatment time the hydrocarbon products decreased, the SP value was lower and the TPPE activity was smaller. It is suggested that the adsorbed oxygen present at the electrode surfaces can lead to an increase in the number of electrons available at the surfaces and also contribute to the adsorption of CO 2 , resulting in hydrocarbon production.

The surface electronic states of 15 kinds of real metals have been investigated by temperature programmed photoelectron emission (TPPE) and XPS. The characteristics of the TPPE method are the amount of emitted photoelectrons (PE total count) and the photoelectric threshold value measured at different temperatures in the temperature-increase and subsequent temperature-decrease process. The metal surfaces were pretreated using ultrasonic cleaning in acetone (T1) and exposure to argon plasma (T2). The characteristics depended strongly on the metals and the pretreatments. The PE total count and threshold value for T1 and T2 were compared: for the PE total count the metals with the order T1>T2 were Pt, Cu, Ag, Au, Ta, Nb, and Co, those with almost the same level (T1≈T2) were Al, Pb, W, Ti, and Mo, and those with the order T1 T2 was Sn, those with almost the same level (T1≈T2) were Al, Pb, Au, Ni, Ta, W, Mo, Nb, Co, and Fe, those with the order T1

To easily characterize the state of real metal surfaces in ambient environments, we have developed an extremely sensitive technique for the surface analysis using photoelectron emission phenomena depending on temperature. We call this method temperature programmed photoelectron emission (TPPE). The emitted electrons were detected by a gas-flow Geiger counter with Q gas. A PE spectrum representing the curve of the PE intensity vs. wavelength was obtained at different temperatures in the temperature-increase and subsequent temperature-decrease process between 25 and 350°C. The number of emitted electrons in a PE spectrum (PE total count) as a function of the measurement temperature was investigated for 17 kinds of rolled metal sheets that were cleaned in acetone. The metals were distinctly classified into five groups A-I (Al, Pt, Pb), A-II (Ag, Cu, Au, Ni), B-III (Ta), B-IV (Pd, W, Ti, Mo), and B-V (Nb, Fe, Zn, Co, Sn). The A groups indicated a temperature dependent PE total count, while the B groups indicated a virtually temperature independent PE total count. With the A groups a greater amount of the adsorbed oxygen that was present on the initial surface was found by XPS to change to oxide oxygen after TPPE measurement, with the exception of Al. This chemical change is suggested to play a substantial role in the temperature dependence of the PE total count. With the B groups oxide oxygen existed predominantly on the initial surface, resulting in little change in the chemical state of the oxygen. It is suggested that the ability of the metals in gas chemisorption is closely related to the TPPE behavior.

To characterize easily the state of real metal surfaces in ambient environments, we have developed an extremely sensitive technique for surface analysis using photoelectron emission phenomena as a function of temperature. We will call this method temperature-programmed photoelectron emission (TPPE). The emitted electrons are detected by a gas-flow Geiger counter with Q gas. The TPPE measurement is performed by scanning the wavelength of incident UV light at different temperatures in the temperature-increase and subsequent temperature-decrease process between 25 and 350°C. A photoelectron emission (PE) spectrum representing the curve of PE intensity vs wavelength is obtained at each temperature. The number of emitted electrons in a PE spectrum is termed PE total count. The PE total count as a function of the measurement temperature was investigated for 17 kinds of commercial rolled metal sheets. The metals were distinctly classified into two main groups A and B, the former indicating a temperature-dependent PE total count and the latter a virtually temperature-independent PE total count. Group A included Al, Pt, Pb, Cu, Ag, Au and Ni; group B included Ta, Ti, Mo, Pd, W, Fe, Co, Zn, Nb and Sn. With group A, the greater amount of adsorbed oxygen present at the initial surface was found by XPS to change to the oxide oxygen after TPPE measurement. This chemical change is suggested to play a substantial role in the temperature dependence of the PE total count.

Aspects of argon plasma treatment of tetrafluoroethylene-perfluoropropylvinylether copolymer (PFA) films, followed by air exposure and its subsequent reaction with 3-aminopropyltriethoxy silane (3-APS) have been investigated using XPS and electron spin resonance (ESR) to gain a better understanding about the surface bonding between the modified PFA and 3-APS. The plasma treatment was performed under varying parameters such as radiofrequency power, gas pressure and treatment time. A good correlation was found between the atomic ratios of O/F and Si/F for PFA before and after the reaction with 3-APS. The amount of peroxy radicals before the reaction with 3-APS was also closely related with the atomic ratio of Si/F. By the derivatization reaction of plasma-treated PFA with NaOH it was confirmed that -C(O)OH groups exist on the treated PFA surfaces. These observations revealed that the oxygen incorporated at the surface leading to -C(O)OH groups plays a substantial role as the reaction site for 3-APS. A similar trend was found between the atomic ratios of Na/F and Si/F after the reactions with NaOH and 3-APS. Based on this observation it is proposed that the surface bonding of 3-APS to the -C(O)OH group at the surface occurs through its -NH 2 group. The analysis of the atomic ratios of O/F, N/F and Si/F after the reaction with 3-APS revealed that a polyaminosiloxane oligomer with a stoichiometry different from that expected for the original 3-APS is formed. The wettability of 3-APS-bound PFA was found to become much greater than that of PFA plasma treated alone. The ageing effect of the wettability of 3-APS-bound PFA was observed, whereas the Si atomic concentration at the surface remained nearly unchanged during ageing.

The temperature dependence of photoelectric emission and its spectral yield has been studied for Si (100) wafer surfaces with a native oxide film. The emission measurement was performed using a gas-flow Geiger counter developed for examining real surfaces. The saturation emission observed as a function of temperatures between 26 and 350 °C under illumination with far ultraviolet rays had the average activation energy of 0.27 eV in the Arrhenius plot. The analysis of the spectral yield observed after the preillumination gave two almost temperature independent photoelectric thresholds of 4.84 ± 0.11 and 5.57 ± 0.15 eV. The difference between the former value and the indirect optical excitation threshold for a clean, cleaved silicon surface reported by Gobeli and Allen approximately agrees with the activation energy. This energy is interpreted as being due to a thermal process for electron transport from the silicon substrate to the SiO 2 /Si interface states. A new emitting center with optical activation energy of about 5.7 eV was also found for the preilluminated surfaces.

The tribochemical reaction of ethanol on oxidized nickel surfaces was studied using gas chromatography, XPS, and exoelectron emission (EEE) and surface potential (SP) measurements. Ametal surface intentionally oxidized by heating in air at 25-800°C was rubbed with the same metal sample in ethanol vapor. EEE was measured using a Geiger counter with Ar-C2H5OH counter gas. SP was measured by a vibrating reed electrometer. Two gaseous products formed with and without friction--acetaldehyde (A) and an unidentified species (B) containing a carbonyl group. Friction increased products and EEE. Products tended to increase with EEE regardless of friction. Product formation was accompanied by carbon deposition. SP for surfaces oxidized at higher temperatures was negative, but after the reaction increased positively due to carbon deposition. The change in SP correlates with the activated tribochemical reaction, EEE appears to originate when negative charge on the oxidized surface is released due to the reduction by ethanol.

The characteristics of the photoelectron emission (PE), measured by varying the wavelength of incident light, form copper subjected to oxidation treatment in air have been investigated as a function of the measurement temperature between 25 and 300°C using a gas-flow counter. The intensity of PE at a certain measurement temperature decreased with increasing oxidation temperature (100 to 800°C) and the intensity of PE for a given oxidation temperature increased with decreasing measurement temperature. The PE behavior was correlated to the chemical and electrical nature of the surfaces analyzed by X-ray photoelectron spectroscopy and surface potential measurement. A mechanism is proposed for the PE of the untreated sample which exhibited a completely different PE behavior.

Plasma oxidation of Ti, Cu and Ni was carried out using a conventional diode-type glow discharge system. Structural and photoelectrochemical properties of the oxide layers formed were examined. Electron diffraction confirmed the formation of a TiO2, Cu2O/CuO, and NiO layer on the Ti, Cu, and Ni surfaces, respectively, after the plasma oxidation. Photoelectrochemical solar cells were fabricated using the oxide layers formed as a semiconductor electrode. The TiO2 electrodes showed moderate photoresponse under anodic potentials in a methanol aqueous solution, while the Cu2O/CuO and NiO electrodes showed a weak photoresponse under cathodic potentials. In conclusion, the TiO2 layers prepared by plasma oxidation work well as a semiconductor electrode for a photoelectrochemical cell and are stable in methanol solution.

In order to increase the hydrophobicity of an organic photoreceptor (OPC) surface for contact charging with a wet polymer roller, surface fluorination treatment was carried out on OPC drums using CF4 rf plasma, and the charging characteristics and surface properties were examined. The hydrophobicity of the plasma-treated OPC drum surface was evaluated by measuring the water contact angle and the water extinction time due to evaporation. It was confirmed that the hydrophobicity of the OPC drum surface was improved considerably by the plasma treatment with little influence on the contact charging characteristics. XPS analysis indicated that fluorine was introduced into the OPC surface by the plasma treatment and its fraction increased with an increase in the treatment time. Further, the XPS spectra suggested that CF, CF2 and CF3 bonds existed on the plasma-treated OPC surface.

The fluorination of expanded graphite sheets using polytetrafluoroethylene (PTFE) Ar plasma sputtering was investigated. The graphite sheet was exposed to Ar plasma between two PTFE sheets. The content of fluorine and oxygen at the graphite surface was correlated as a function of plasma treatment power and temperature with the nature of water wettability and surface potential (SP). The fluorine content increased with increasing power and temperature, resulting in increased hydrophobic nature. Water wettability and the electrical nature of the front of the sheet in contact with Ar plasma differed greatly from those on the back of the sheet: the front was more hydrophobic when power was changed, but more hydrophilic when temperature was changed. The SP value for the front became negative, nearly independent of power and temperature. The back still exhibited a positive SP value, the same as an untreated sheet.

The characteristics of photoelectron emission (PE) from copper abraded in organic liquids such as alcohols, aromatics, ether, ketone, and ester have been investigated. PE was measured by varying the wavelength of incident light at several temperatures between 25 and 300°C, which were successively changed in two round cycles of elevating and lowering temperatures. PE intensity depended greatly on the measurement temperature. The maximum PE appearing at 250°C in the temperature-elevation of the first cycle, also, depended markedly on the organic liquids used. The order of the maximum PE value for organic liquids was explained as corresponding significantly with that of the acid base interaction of the organic liquid and abraded surface.

The adhesion strength of fluorine-containing rubber (a copolymer of CF2=CH2 and CF2=CF-CF3) to plasma treated aluminum was studied using X-ray photoelectron spectroscopy data and the water contact angle. Plasma treatments were as follows. (a) argon plasma treatment of aluminum at elevated temperatures in the presence of polytetrafluoroethylene (PTFE), sputtering PTFE onto the metal surface and (b) argon plasma treatments in the absence or in the presence of PTFE of plasma polymerized film (PPF) of cyclohexane previously formed on the aluminum surface. Adhesion was conducted by inserting rubber between two treated aluminum samples and adding compressive stress at high temperature. Adhesive strength was measured using Instron test equipment. Adhesive strength using treatment (a) was much greater than without treatment and slowly increased with increasing temperature, being due to the removal of carbon contaminants and the introduction of CF2 groups on the surface. Adhesive strength using treatment (b) increased several times compared to that without plasma treatments. The PPF surface after treatment (b) exhibited a hydrophihc nature, thought to play a significant role in adhesion.

Plasma polymerized films of carbocyclic compounds such as C6H12, C6H6, C6H5CH3, C6H5NH2, C3H5Cl, and C6H5OH were deposited on expanded graphite sheets and film durability was investigated by measuring cathodic polarization curves in aerated NaCl solution. The polymer film-coated sheets were employed as the working electrode. The films of hydrocarbons having a highly crosslinked structure (C6H12, C6H6, and C6H5CH3) inhibited cathodic reactions, and in these cases the main reaction is thought be oxygen reduction: H2O+1/2O2+2e-=2OH-. But in the other compounds studied, little inhibition occurred. In the hydrocarbons, cathodic activity was related to the O1s/C1s ratio obtained by X-ray photoelectron spectroscopy (XPS) and to the surface potential (SP) measured by a conventional vibrating electrode method. The cathodic reaction activity of the films decreased as the oxygen content decreased and as the surface potential decreased. It is suggested that the chemical and electrical nature of the hydrocarbon films plays an important role in cathodic reaction activity. Anodic polarization was also carried out for the C6H12 and C5H5OH films. The trend in the inhibiting effect was similar to that for cathodic polarization.

An analytically exact solution based on the thermionic exoelectron emission model is obtained for thermally stimulated exoelectron emission (TSEE) glow curves. The theoretical TSEE glow curve is dependent on the values of trap depth and electron affinity. Moreover, the equation indicates that when the experimental glow curve is subject to the conventional first-order kinetics, the thermal activation energy is the electron affinity but not the trap depth. The equation can be compared with the experimental TSEE glow curves by the curve fitting technique. Eine exakte analytische Losung fur die TSEE-Glowkurven wird aufgrund des Exoelektronen-Emissions-Modells erhalten. Die theoretische TSEE-Glowkurve hangt von der Haftstellentiefe und der Elektronenaffinitat ab. Die experimentelle Glowkurve folgt der konventionellen Kinetik erster Ordnung, die thermische Aktivierungsenergie ist die Elektronenaffinitat und nicht die Haftstellentiefe. Theorie und Experiment werden mittels Kurvenanpassung verglichen.

Mechanical rubbing of polyimide (PI) films is used to homogeneously align liquid crystal molecules on the surface. The chemical structure of aromatic PI surfaces subjected to rubbing has been analyzed by X-ray photoelectron spectroscopy, and the frictional charging and surface states of the PI films have also been investigated by measurements of surface potential (SP) and photoelectric emission (PE). Six kinds of PI films were prepared by reacting two diamines containing CH3 and CF3 functional groups with three tetracarboxylic dianhydrides. Rubbing of the films caused the O content to increase, while the N and F contents decreased. The fraction of the two oxygen components (-O- and C=O) of the films was changed by the rubbing. The films with CF3 groups exhibited much more negative charging (negative SP) than those with CH3 groups. It is suggested that the order of the charging of the films with CF3 and CH3 groups closely depends on the ratio by which the F and N elements, respectively, were reduced by the rubbing. Both with and without rubbing, the films with CH2 groups gave a considerably larger PE level than those with CF3 groups. This suggests that the electron trap levels responsible for the negative charging in the latter films make virtually no contribution to PE.

The effects of structural modification caused by substitution of Mo for a part of V in V 2 O 2 on structural changes upon lithium insertion were investigated. For this purpose (V 1-y Mo y ) 2 O 5 (y = 0.25) was synthesized, and its insertion behavior and structural changes upon lithium insertion were analyzed by XRD and ESR methods. In (V 0.75 Mo 0.25 ) 2 O 5 , the phases except for the starting material were not observed upon lithium insertion, and no phase transformation characteristics of V 2 O 5 occurred. From ESR measurement, a broad singlet signal of V(IV) was found, but those of Mo(V) were not detected. The line width of the signal V(IV) increased steeply at 0.7 < x < 1. The open circuit potentials became less noble with increasing x, and dropped steeply at 0.7 < x < 1. These dependencies closely correlate with structural changes estimated from results of ESR and XRD analyses. At 2.7 < x, ω-phase oxide was formed.

We have investigated the thermally stimulated exoelectron emission (TSEE) from graphite surfaces exposed to O2, CF4, and Ar plasmas in combination with the measurements of surface potential (SP) and x‐ray photoelectron spectroscopy (XPS). The surfaces exposed to the plasmas were left in the ambient air prior to the measurements. The TSEE glow curves, the change in SP, and the XPS spectra were examined as a function of plasma exposure time and pressure. The TSEE glow curves for each plasma gas exhibited one sharp emission peak (peak I) at ∼98 °C, the intensity of peak I decreasing in the order, O2≳CF4≳Ar. Furthermore, for CF4 plasma a broad peak (peak II) was also observed at ∼250 °C. The SP for the surfaces exposed to the plasmas became highly negative, decreasing in the order, Ar≳O2≳CF4. This can be attributed to an increase in the O and F contents on the surface. The change in SP after the plasma treatment was nearly reversed to the original value in each case after the TSEE measurement. The origins for...