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1.
Ederth T Tamada K Claesson PM Valiokas R Colorado R Graupe M Shmakova OE Lee TR 《Journal of colloid and interface science》2001,235(2):391-397
Long-range interactions between self-assembled monolayers (SAMs) of semifluorinated alkanethiols have been studied by direct force measurements in water and aqueous NaCl solutions. SAMs prepared from three different thiols, with identical fluorinated head groups but varying hydrocarbon spacer lengths, were investigated: CF(3)(CF(2))(9)(CH(2))(x)SH, where x=2, 11, or 17. Force measurements show that the interactions in water and electrolyte solutions are composed of both double-layer interactions emerging from what appears to be charges adsorbed onto the surfaces and long-range "hydrophobic" attractions, in excess of the expected van der Waals forces. The three investigated thiols produce similar results in force measurements, though the contact angles with water are slightly different. The "hydrophobic" attraction has the form of step-like attractive discontinuities in the force profiles at separations ranging from 20 to 40 nm, caused by bridging of microscopic bubbles residing at the surfaces. The shape or range of these discontinuities are not significantly affected by replacement of the water with either 1 mM or 1 M NaCl solutions. The origin of the charges causing the electrostatic double-layer interaction is unclear, but some possible causes are discussed. Copyright 2001 Academic Press. 相似文献
2.
V. V. Kochervinskii E. V. Chubunova Yu. Yu. Lebedinskii N. A. Shmakova 《Polymer Science Series A》2011,53(10):912-928
High-voltage polarization processes occurring in alternating fields of various frequencies in extruded films of vinylidene
fluoride-hexafluoropropylene copolymers are studied. Remanent polarization typical for ferroelectric polymers with a polar
cell appears during crystallization in the nonpolar α phase. This effect is associated with the presence of a highly imperfect
ferroelectric (or antiferroelectric) phase in the copolymer, where chains assume planar zigzag conformations. The magnitude
of remanent polarization depends on the frequency of the applied bipolar sawtooth voltage. This observation may be explained
by the fact that the resulting field is created not only by the external source but also by the space charge that is contributed
by carriers injected from electrodes. With the use of deposited Au and Al, the role of electrode material in polarization
and conduction processes is ascertained. In the case of Al, Al2O3 and new Al-C chemical bonds are formed on the polymer surface. Owing to formation of these additional dielectric layers at
the copolymer/metal interface, electrodes may be blocked partially. The above new chemical bonds facilitate formation of deeper
surface traps for carriers; as a result, the remanent surface potential appears in polarized samples even after storage in
the short-circuit mode. 相似文献
3.
M. S. Piskarev A. B. Gil’man N. A. Shmakova M. Yu. Yablokov E. M. Smul’skaya A. A. Kuznetsov 《High Energy Chemistry》2008,42(6):498-502
The effect of dc discharge treatment at the anode and cathode on the surface properties of tetrafluoroethylene-hexafluoropropylene copolymer films was studied. It was found that the modification of the films under conditions that ensure the separation of the discharge active species acting on the polymer materials makes it possible to achieve substantially lower values for the contact angle and higher values for the work of adhesion and surface energy than in the case of other modes of discharge. A change in the composition and structure of the films was studied by means of IR and X-ray photoelectron spectroscopy. It was found that new oxygen-containing groups are formed on the polymer surface as a result of plasma discharge treatment. 相似文献
4.
A. B. Gil’man M. S. Piskarev O. V. Starichenko N. A. Shmakova M. Yu. Yablokov A. A. Kuznetsov 《High Energy Chemistry》2008,42(4):326-329
The surface properties of polypropylene (PP) films modified in a direct-current discharge at the anode and cathode, as well as their change during long-term storage were studied. It was shown that the greatest decrease in the contact angles and the increase in the total surface energy and the polar component are observed for the films treated at the anode. Changes in the chemical structure of PP films were investigated by means of Fourier-transform IR spectroscopy and X-ray photoelectron spectroscopy techniques. 相似文献
5.
A. B. Gil’man M. S. Piskarev M. Yu. Yablokov N. M. Surin N. A. Shmakova A. A. Kuznetsov 《High Energy Chemistry》2012,46(6):375-380
Changes induced in the surface properties of films of a tetrafluoroethylene copolymer with perfluoropropylvinyl ether by direct-current discharge have been investigated, depending on the discharge parameters. It has been shown that the treatment of the films at the anode is more effective than at the cathode. A change in the contact properties of the modified films during their storage in air under ambient conditions and upon heating to 150°C has been examined. The chemical composition of the surface of the films after modification, storage, and heating has been studied by X-ray photoelectron spectroscopy and Fouriertransform IR spectroscopy. It has been found that dc discharge treatment significantly improves the adhesion properties of the films and barely affects their light transmission. 相似文献
6.
A procedure is developed for estimating the temperature dependence of the liquid density on the basis of a minimum set of input data. 相似文献
7.
N. E. Shmakova 《Acoustical Physics》2004,50(2):236-236
Information
XV Session of the Russian Acoustical Society 相似文献8.
9.
Carbohydrate-containing peptides were found among the products of the enzymic breakdown of egg albumin. All these peptides contained a constant group of five amino acids (arginine, glutamie acid, alanine, proline, and valine), and in basic peptides lysine was present also. 相似文献
10.
I. V. Semenov A. B. Gil’man M. Yu. Yablokov N. M. Surin A. N. Shchegolikhin N. A. Shmakova A. A. Kuznetsov 《High Energy Chemistry》2011,45(2):157-161
Thin 1-aminonaphthalene polymer films have been obtained for the first time by polymerization at the cathode and anode in
dc discharge. The elemental composition, chemical structure, and thermal stability of the polymer have been studied by pyrolysis
chromatography, IR and UV spectroscopy, and thermogravimetry, respectively. The surface contact properties of the films and
their thickness have been determined with a microinterferometer. 相似文献