Ionic electroactive polymers are considered as electromechanical and mechanoelectrical transducers - actuators and sensors. Transducers with metal (Pt), polymer (PEDOT), and polymer-metal (PEDOT/Pt) hybrid electrodes are prepared. The surface morphology and internal structures of the samples are studied. The measurements of practically important actuation characteristics show that the advantages of transducers with earlier types of electrodes are inherited by those with hybrid electrodes: longer continuous operation in air characteristic of polymer electrodes and higher amplitude and force properties characteristic of metal ones. In the study of the transducer with PEDOT/Pt-electrodes in the sensor mode, the most stable response is obtained when Pt is deposited on the PEDOT external surface in two stages.

Рассмотрены ионные электроактивные полимеры в качестве электромеханических и механоэлектрических преобразователей — актюаторов и сенсоров. Изготовлены преобразователи с металлическими (Pt), полимерными (PEDOT) и полимер-металлическими (PEDOT/Pt) гибридными электродами. Исследованы морфология поверхности и внутренняя структура образцов. Измерения практически значимых актюационных характеристик показывают, что преобразователи с гибридными электродами наследуют преимущества преобразователей с более ранними типами электродов: бóльшая продолжительность непрерывной работы на воздухе, присущая полимерным электродам, и более высокие амплитудные и силовые свойства, присущие металлическим электродам. При исследовании преобразователя с PEDOT/Pt-электродами в режиме сенсора наиболее стабильный отклик получен при двухстадийном нанесении Pt на внешнюю поверхность PEDOT.

It is proposed that the criterion of rapid heating be used to synthesize diamond on the basis of a carbonate–silicate matrix in the form of a melt. The criterion was analyzed in earlier parts of this work and used in the proposed approach so that the temperature of a melt layer grew rapidly from a minimum melting temperature of ~800 to ~1400 K in a time on the order of several seconds. When this happens, conditions arise in a standard gas-phase mixture of CO + CH4 + CO that ensure the formation of diamond nuclei and are better than those for the nucleation of graphite nuclei.

Рассматриваются микромеханические сенсоры на основе полимерной ионообменной мембраны с металлическими и полимерными электродами — ионных полимер-метал­лических композитов (ИПМК) и ионных полимер-полимерных композитов (ИППК). Исследования сенсоров размерами 20×5×0.3 мм проводились при пропитке различными электролитами: деионизованной водой, водным 0.1 М раствором CuSO4, этиленгликолем и ионной жидкостью. Показано, что ИПМК-сенсоры, пропитанные деионизованной водой, характеризуются наибольшим откликом (130 мВ/см). Добавление CuSO4 приводит к уменьшению выходного напряжения ИПМК- и ИППК-сенсоров. Напротив, большим временем непрерывной работы характеризуются ИПМК- и ИППК-сенсоры, пропитанные этиленгликолем и ионной жидкостью. Уменьшение выходного напряжения при переходе от деионизованной воды к этиленгликолю и ионной жидкости сильнее проявляется в ИПМК-сенсорах.

It is shown that the predominant nucleation of diamond nuclei (instead of graphite ones) in plasma or hot-filament assisted CVD technology is due to a sharp increase in the temperature of the region of the initial gas mixture’s motion. The nucleation of diamond nuclei then occurs immediately in the gas phase. The reason for such predominant nucleation is high oversaturation by small hydrocarbon fragments in the gas mixture, due to a rapid change in temperature and substantial differences between the desorption of such fragments from the surfaces of nuclei and the oxidation of nuclei. A way is described of synthesizing massive diamonds without the use of high pressures and CVD technology in its traditional form.

We consider micromechanical sensors based on a polymer ion-exchange membrane with metal and polymer electrodes: ionic polymer-metal composites (IPMCs) and ionic polymer-polymer composites (IP2Cs). The 20×5×0.3 mm sensors are studied when impregnated with various electrolytes such as deionized water, aqueous 0.1 M CuSO4 solution, ethylene glycol, and ionic liquid. It is shown that IPMC sensors impregnated with deionized water exhibit the strongest response (130 mV/cm). Adding CuSO4 decreases the output voltage of IPMC and IP2C sensors. To the contrary, IPMC and IP2C sensors impregnated with ethylene glycol and ionic liquid show longer times of continuous work. The decrease of output voltage in the case of ethylene glycol and ionic liquid compared to deionized water is most pronounced in IPMC sensors.

A study is performed of elementary processes that occur during the transformation of a standard gas mixture for the CVD synthesis of diamond upon a rapid rise in temperature. The analysis creates a basis for solving the problem of the nucleation of carbon nucleating agents, showing that a rapid rise in temperature stimulates the predominant nucleation of diamond (rather than graphite) nucleating agents. The reason for this at the level of elementary processes is the similarity of the evaporation of graphite and diamond nucleating agents and the considerable difference between oxidation processes, which in contrast manifest notably upon a rapid change in the conditions of nucleation. The study provides a way of synthesizing massive diamonds that does not require the use of high pressures or the technology of CVD in its traditional form.

Operation features of actuators based on the domestic electroactive polymer MF-4SK in combination with graphene electrodes is first studied. This system demonstrates several advantages, e.g. better mutual adhesion of materials, over those employing conventional flexible metal electrodes and Nafion membranes. The reported model of electroactive polymers connects sizes and structure of water-filled pores to geometrical characteristics of polymers with the goal of comparing properties of MF-4SK and Nafion polymers.

The operation of actuators based on ionic polymer-metal composite using domestic polymer MF-4SK as a material for the polymer membrane is first studied. The polymer has a number of advantages compared to its foreign analog Nafion. Despite a well-known effect of ion mobility reduction, the composite demonstrates better actuation characteristics, namely, a larger amplitude of membrane deflection and a greater blocking force under the action of both constant and sinusoidal voltages.

Впервые исследована работа актюаторов на основе ионного полимер-металлического композита, в которых в качестве материала полимерной мембраны выступает отечественный полимер МФ-4СК, обеспечивающий ряд преимуществ по сравнению с зарубежным аналогом (Нафионом). Несмотря на известный эффект снижения ионной подвижности, композит демонстрирует усиление актюационных характеристик: увеличение амплитуды отклонения мембраны и блокирующей силы под действием как постоянного, так и синусоидального напряжения.

Впервые исследована специфика работы актюатора на основе отечественного электроактивного полимера МФ-4СК в комбинации с графеновыми электродами. Система показала ряд преимуществ по сравнению с теми, в которых используются традиционные гибкие металлические электроды, а также нафионовые мембраны, в частности лучшую взаимную адгезию материалов. Построена модель электроактивного полимера, связывающая размеры и структуру водонаполненных пор с геометрическими характеристиками полимера и ориентированная на сопоставление свойств полимера МФ-4СК и нафиона.

Experimental samples of ionic electroactive actuators with poly(3,4-ethylenedioxythiophene) electrodes (PEDOT) have been developed and produced. Measurements of amplitudes of a displacement, frequency and power characteristics of produced actuators were carried out. The influence of the membrane solvent, as well as the influence of the EDOT polymerization time on the sample structure and the output characteristics of actuators, was determined.

Methyl pheophorbide a reacts with terpene alcohols on activation with the Mukaiyama reagent to give the products of the formal transesterification of the C(21)CO2Me group. To increase hydrophilicity, the synthesized conjugates were modified following two different paths. The first path is the acid-catalyzed transesterification of the C(3)(CH2)(2)CO2Me moiety of the conjugate with triethylene glycol to give diester with different substituents and different ester groups. The second path is the treatment of terpenyl ester with N,N-dimethylethylenediamine that proceeds via the phorbin exocycle opening to give the porphine derivatives bearing two ester and one carboxamide groups. The dimethylamino groups of these porphine derivatives were quaternized with iodomethane.

The maximum size of homogeneous monolayer graphene flakes that form during the high-temperature evaporation of silicon from a surface of SiC or during graphene synthesis via chemical vapor deposition is estimated, based on the theoretical calculations developed in this work. Conditions conducive to the fragmentation of a monolayer graphene sheet to form discrete fragments or terrace-type structures in which excess energy due to dangling bonds at the edges is compensated for by the lack of internal stress are indentified and described. The results from calculations for the sizes of graphene structures are compared with experimental findings for the most successful graphene syntheses reported in the literature.

A model is proposed that describes the structure of water filled Nafion-graphene composite forming the body of an electroactive polymer membrane for actuators of biomimetic systems able to work in air and a liquid medium. The model predicts the growth of the ionic conductivity with increasing concentration of a graphene modifier, which is due to that the size of a part of clusters of the Nafion framework containing hydrophobic graphene flakes enlarges together with the pore size. Then the optimal concentration of the graphene modifier is reached, which provides the maximum ionic conductivity and actuation ability of the membrane as well as its elastic properties. The possibility of introducing into Nafion the modifier amount needed to improve the actuator operation is experimentally tested.

The research of the graphene was carried out with regard to problem of actuators for biomimetic systems. The graphene was tested in two applications: as an additive to the electroactive polymer (Nafion) membrane to provide a faster cation transfer through the body of the Nafion membrane and as a principal material of the membrane electrode that ensures the voltage supply across the Nafion membrane. In the second case, high resistance of the polycrystalline graphene electrode is compensated by silver additives. The models were developed for the both composite structures. In the first case, the model defines the optimal quantity of the graphene in the Nafion membrane, in the second case the optimal quantity of silver in the graphene can be determined.