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It has recently been reported that thin films of perfluoropolyethers (PFPE's) can be bonded to a variety of substrates under illumination of 185-nm ultraviolet (UV) light. In this paper we examine the bonding of thin perfluoropolyether films by low-energy electrons and UV light. It is shown that the bonding takes place through interaction of the perfluoropolyether molecule, with a low-energy photoelectron created by excitation of the substrate by the UV photons. The perfluoropolyether molecule subsequently undergoes a dissociative electron attachment, resulting in the formation of a radical and a F-ion. It is likely that radical propagation and termination steps then cross-link the polymer and attach it to the substrate. The similarities and differences between electron-bonded and UV-bonded perfluoropolyether films are discussed.

H2 and NH3 were produced when a suspension of Fe203 catalyst particles or sintered pellets in water were illuminated with light of energy greater than 2.3 eV. Catalytic action was demonstrated by detecting H2 yields many times the stoichiometric equivalent of the measured (by X-ray diffraction, Móssbauer spectroscopy, and oxidimetry) Fe(II) content of the catalyst, up to 80X for H2 and 20X for NH3. The initial rate of formation of H2 was 40 µ /h-g of catalyst and of NH3 was 10 µ /h-g of catalyst. The formation

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We report studies of the effect of humidity and the chemical nature of the molecular end groups on the structure and spatial distribution of perfluorinated lubricants on hard carbon substrates. The studies are performed with a noncontact atomic force microscopy (AFM) technique that is capable of providing nanometer scale images of soft and liquid surfaces. Our results indicate that reactive end groups enhance the wear resistivity of the lubricants. ZDOL and ZDIAC, which have CH 2OH and COOH end groups, respectively, could not be displaced by a sharp tip (≈500 Å radius) under a load of 1 × 10 -8 N while, under the same conditions, Z03, which has CF3 groups at both ends, and Demnum SA, which has a CF3 group and a CH2OH group at each end, could be easily displaced. We found that humidity enhances the mobility of the lubricants. Humidity also causes dramatic changes in the state of aggregation of ZDIAC and Demnum SA. The binding of these lubricants to the surface becomes unstable, and upon contact with the tip, they dewet the surface to form solid-like or liquid-like agglomerates.

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The photodissociation of H 2 0 on partially reduced Fe203 powders and pellets is shown to be a catalytic process if the semiconductor is illuminated by visible light of energy greater than 2.2 eV. Activation of the Fe203 catalysts involved reduction in a mixture of H2 and H 2 0 followed by oxidation. Up to 380 pnol of H2 were produced with 190 kmol of Fe203 the U S . Department of Energy under Contract No. DE-AC03-76SF00098. One of the authors (M.M.K.) thanks the Egyptian Ministry of Education for the award of a fellowship. Registry No.