The esteemed author of the Comment presents a calculation of the number of charges per unit pore sur� face based on the classical theory of the electrical dou� ble layer. Such calculations were performed previously as well. We called attention for the first time to the dif� ference between the charge magnitudes determined from the streaming potential and pore conductivity when studying glass reverseosmosis membranes (1). Analogous results were later obtained by different authors when investigating polymer ultrafiltration and reverseosmosis membranes, porous glasses, rocks, etc. This fact may be related to the difference between the total charge of a pore and the electrokinetic charge, which is always lower than the total charge. Moreover, it may be associated with the discreteness of charges, which is not taken into account in the classi� cal theory of the electrical double layer. Therefore, it is quite unclear why the low charge magnitude in fine pores determined from the streaming potential must, in the opinion of the author of the Comment, serve as the evidence of the absence of these pores. As can be seen from the title of the article, the main goal of our work was to study the electrosurface prop� erties (surface conductivity, charge, and isoelectric point) of latent tracks in a poly(ethylene terephtha� late) film irradiated with highenergy ions. We did not investigate the mechanism of gas flow through the latent tracks. Of course, some model is required for studying the electrosurface properties. We selected the model of a cylindrical channel the wall of which is covered with a porous, loose layer. If a liquid flow inside this layer should be considered to be the surface diffusion is, in our opinion, a question of terminology. The presence of the porous layer on the pore sur�

Poly(ethylene terephthalate) films irradiated by high-energy ions without additional etching have been studied. It has been shown that tracks of heavy high-energy ions in poly(ethylene terephthalate) may be considered to be single through capillaries suitable for studying electrophysical properties. It has been revealed that the surface electrical conductivities of electrolyte solutions (KCl, LiCl, MgCl 2 , and BaCl 2 ) in the tracks of nonetched membranes are substantially higher, while the surface charges are noticeably lower, than those of etched membranes.

Исследованы пленки из полиэтилентерефталата после облучения высокоэнергетическими ионами без дополнительного травления. Показано, что треки тяжелых высокоэнергетических ионов в полиэтилентерефталате можно рассматривать как единичные сквозные нанокапилляры, пригодные для исследования электрофизических свойств. Обнаружены значительное повышение поверхностной электропроводности растворов электролитов (KCl, LiCl, MgCl2 и BaCl2) в треках непротравленных мембран и, в то же время, значительно меньшие значения поверхностного заряда по сравнению с протравленными мембранами.

The electrosurface characteristics are studied for poly(ethylene terephthalate) (PET) track membranes (TMs) with pore radii of 6.5–60 nm, which are used for ultra- and microfiltration. The data obtained enable one to indirectly assess the structure of tracks and variations in the pore space structure of TMs with an increase in the pore radii. Higher porosity values obtained for TMs from the data on their electrical resistance in comparison with those derived from the filtration data lead one to state that the PET pore surface has a loose structure. The thermal treatment of TMs makes the porosity values determined by the methods of electrical resistance and filtration closer to one another. The regularities of variations in the isoelectric point, ζ potential, and surface charge suggest that the properties and structure of PET pore surface depend on the pore radius. The data obtained may be used to predict the separating power of TMs.

Изучены электроповерхностные характеристики трековых мембран (ТМ) из полиэтилентерефталата (ПЭТФ) с радиусами пор от 6.5 до 60 нм, используемых для ультра и микрофильтрации. Результаты исследований позволяют косвенно судить о структуре трека и об изменении структуры порового пространства ТМ по мере увеличения радиуса пор. Более высокие значения пористости ТМ, определенные из данных по электрическому сопротивлению мембран, по сравнению со значениями пористости, полученными из фильтрационных данных, позволяют утверждать, что поверхность пор ПЭТФ имеет рыхлую структуру. При термообработке ТМ происходит сближение значений пористости, определенных из данных по электрическому сопротивлению и фильтрации. Закономерности изменений изоэлектрической точки, -потенциала и поверхностного заряда свидетельствуют о том, что свойства и структура поверхности пор ПЭТФ зависят от их радиуса. Полученные результаты могут быть использованы для прогнозирования разделительной способности ТМ.

This article looks at the effect of orientation stretching of irradiated polyethylene terephthalate films on the shape of the pores formed during chemical pore etching. Shows that orientation stretching enables latent tracks in the polymer to be stretched, which gives rise to track membranes with elliptical pores. Examines the effect of deformation of irradiated polymer on the structure and physical/mechanical characteristics of the track membranes formed. It is assumed that the change in the polymer structure resulting from heavy-ion irradiation may be linked to local heating at the locations where the charged particles pass.

It is shown that the orientation of polymer macromolecules after irradiation by heavy ions allows one to produce a polyethyleneterephtalate film with increased mechanical strength and chemical resistance. Chemical etching of such a film results in the formation of elliptical shape pores oriented in the direction of film elongation.

Исследованы особенности травления латентных треков и формирования пор трековых мембран. Показано, что введение в щелочной раствор ионов K+ и Ва2+ ускоряет травление полиэтилентерефталата (ПЭТФ) и латентных треков в нем. Обнаружено, что ускорение травления вызвано уменьшением отрицательного заряда поверхности ПЭТФ и пор трековых мембран. Определена изоэлектрическая точка трековых мембран из ПЭТФ и полиимида. Установлено, что она зависит от диаметра пор. Обнаружено, что с увеличением диаметра от 30 до 70 нм увеличивается отрицательная величина заряда поверхности, что, по-видимому, связано с увеличением концентрации карбоксильных групп на поверхности пор. Предполагается, что этот эффект связан с особой подвижностью карбоксильных групп в геле, образующемся на стенках пор в результате травления латентных треков или в результате смещения плоскости скольжения за счет уменьшения толщены гель-слоя.

The latest Russian and foreign studies devoted to the theoretical and experimental investigation of the processes of formation of porous structure of track nanomembranes, the methods for studying their properties, and the application of track membranes to synthesis of nanostructures by a template method are reviewed. The results of the investigations carried out in these promising directions at the Department of Membrane Technologies of the Shubnikov Institute of Crystallography, Russian Academy of Sciences, are also presented. On the basis of the theoretical investigations of the mechanism of interaction of high-energy ions with a solid, it is shown that the theory of instantaneous explosion in a track region must be carefully verified. The results of the experimental investigation of the structure of tracks of high-energy ions in a polymer and the mechanism of pore formation in the stage of chemical etching of tracks showed that the track structure is inhomogeneous in the radial direction. It is shown that the surface of polyethylene terephthalate track membranes becomes negatively charged in neutral and alkaline solutions, and the value of this charge depends on the pore diameter. Good prospects of application of secondary metal structures formed on the basis of track membranes in mass spectroscopy are demonstrated experimentally.

Polymer (PET) films were irradiated with Ar, Xe and Bi ions (energy up to 3.5 MeV/n and fluence 10''° cm'^ , Dubna). Structure of latent track as well as initial stages of these track etching were investigated. Track radii were found to be 3 nm, 7 nm, 12 nm for Ar, Xe and Bi ions respectively. Termosensitization and contraction of rack were measured: it was found that etching speed grows up to 80° -100° С and decrease by further heating. Possible mechanisms of such behaviour are discussed. Tracks found to have complex structure: track core (7 nm - for Xe-irradiated polymer), zone of destruction (17 nm) and zone of linking (up to 100-150 nm).

The modification of polymer track membranes from polyethylene terephtalate (PET) and polypropylene (PP) was performed by radiation-induced graft polymerization of thermosensitive poly-N-isopropylacrylamide (poly-NIPAAM). The opening and closing of the pores was controlled by temperature and studied by the electric conductivity and water flow methods. The structure of the grafted membranes was investigated by scanning electron and atomic force microscopy.

Products formed in tracks produced by bombarding poly(ethylene terephthalate) with Xe ions are studied. It was found that the most profound changes in the polymer occur in a track region of 15-20 nm radius. It is this region in which the degradation of macromolecules is accompanied by branching and crosslinking: a gel is formed that retards the diffusion of hydroxyl groups into the reaction zone and the reaction products out of it during etching. The effect of the ion on the polymer extends to 50 nm. A model for track structure is proposed.

The thickness of the damaged layer along a particle track in polyimide is estimated by the method of thermally stimulated exoelectron emission and found to be ∼30 nm.