A unit for electrospinning of polymer melts was created. Nonwovens with an average fi bre diameter of 0.5-20 m were obtained from a melt of both pure polyamide 6 and its blends with stearic acid and oleic acid additives in the amount of 2-10 wt. % were obtained. Addition of 10% SF decreases the average diameter of the fi bres obtained by 40 times due to a decrease in the viscosity of the melt by 60 times.Electrospinning is a process for manufacturing ultrathin fi bres from polymer solution or melt under the effect of electrostatic forces. Electrohydrodynamic spraying of liquids (discovered for the fi rst time in 1745 by G. M. Bose [1]), where a weakly conducting liquid fl owing out of a nozzle under high voltage is sprayed into very fi ne drops by repulsive forces that are gradually precipitated on the opposite electrode, is the precursor of electrospinning. Patents for production of fi bre materials by electrospinning from solution were issued to Morton in 1902 in the USA for the fi rst time [2], but a major jump in the development of the solution method occurred in 1938 when I. V. Petryanov-Sokolov and N. D. Rozenblyum, colleagues at the L. Ya. Karpov Moscow Scientifi c-Research Institute of Physical Chemistry, in an attempt to obtain nitrocellulose aerosol from solution in acetone by electrohydrodynamic spraying, unexpectedly ran up against the competing regime of electrospinning of fi bres. Knowing how to evaluate the potential of this discovery, they could implement it in industry relatively rapidly.Fibres were probably obtained from polymer melts by the electrospinning method for the fi rst time in 1981 and described by Larondo and Manley [1]. They manufactured fi bres from polyethylene "solution-melt" in paraffi n and, more importantly, from pure polypropylene melt. The distance to the takeup plate was 1-3 cm, which allowed using an electric fi eld potential of approximately 7 kV without breakthrough of air. The fi bre diameter was greater than 50 m. It was then noted that the size of the fi bres obtained can be controlled by regulating the melt temperature and applied voltage. In addition, it was found that the viscosity is the most important parameter in production of fi bres from polymer melts than from solutions.The electrospinning process has many features. First, the one-time character of conducting all stages, so that a ready-to-use product is obtained at the end. Second, the universality of the method, which provides a broad spectrum of materials. Third, the fl exibility of the method, which allows controlling the structure of the materials. This is why the interest in production of polymer fi bres by electrospinning has now increased sharply.Despite the fact that most of the studies and manufacturing processes were executed for electrospinning of polymer solutions, spinning from polymer melts has a number of advantages.Many polymers (poly(ethylene terephthalate), polyolefi ns, some polyamides) are only soluble in scarce and expensive solvents at high temperature. This limits the use of these pol...
The memristive elements constructed using polymers - polyaniline (PANI) and polyethyleneoxide (PEO) - could be assembled on planar thin films or on 3D fibrous materials. Planar conductive PANI-based materials were made using the Langmuir-Schaefer (LS) method, and the 3D materials - using the electrospinning method which is a scalable technique. We have analyzed the influence of PANI molar mass, natures of solvent and subphase on the crystalline structure, thickness and conductivity of planar LS films, and the influence of PANI molar mass and the PANI-PEO ratio on the morphological and structural characteristics of 3D fibrous materials.
materials makes the elements cheap and easy to manufacture. Moreover, organic materials allow simple chemical modification of the electrophysical properties and fabrication of flexible and stochastic 3D elements. [15-18] One of the first and most studied types of the organic memristive devices are polyaniline (PANI) based devices. [19-26] The structure and electrophysical properties of the PANI-based memristive devices are described elsewhere. [20] The main active component of the device is a thin PANI film connecting two metal electrodes. The third electrode is a silver wire separated from the film by a layer of solid electrolyte. The silver wire ("gate") is always connected to one of the substrate electrodes ("drain"), while the voltage is applied to the second one ("source"), as shown in Figure 1a. The RS is driven by a voltage-controlled electrochemical reaction at the PANI-electrolyte interface. The device switches to the low resistive state (LRS) under applied voltage exceeding the value of +0.4 V and to the high resistive state (HRS) under applied voltage less than +0.1 V. Its conductivity remains quite stable in the window between these values. Nonzero current at zero bias voltage is an essential and inevitable feature of all redox-based memristive devices. [27] The devices were shown to be stable for at least 10 4 switching cycles and able to hold each programmed resistive state for at least 10 3 s. [28,29] A detailed description of the switching mechanism is previously published. [21,22] During the RS, the insulating leucoemeraldine form of PANI transforms into the conductive emeraldine salt form and vice versa according to the following equation
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