Exactly 50 years ago, the first article on electrochromism was published. Today electrochromic materials are highly popular in various devices. Interest in nanostructured electrochromic and nanocomposite organic/inorganic nanostructured electrochromic materials has increased in the last decade. These materials can enhance the electrochemical and electrochromic properties of devices related to them. This article describes electrochromic materials, proposes their classification and systematization for organic inorganic and nanostructured electrochromic materials, identifies their advantages and shortcomings, analyzes current tendencies in the development of nanomaterials used in electrochromic coatings (films) and their practical use in various optical devices for protection from light radiation, in particular, their use as light filters and light modulators for optoelectronic devices, as well as methods for their preparation. The modern technologies of “Smart Windows”, which are based on chromogenic materials and liquid crystals, are analyzed, and their advantages and disadvantages are also given. Various types of chromogenic materials are presented, examples of which include photochromic, thermochromic and gasochromic materials, as well as the main physical effects affecting changes in their optical properties. Additionally, this study describes electrochromic technologies based on WO3 films prepared by different methods, such as electrochemical deposition, magnetron sputtering, spray pyrolysis, sol–gel, etc. An example of an electrochromic “Smart Window” based on WO3 is shown in the article. A modern analysis of electrochromic devices based on nanostructured materials used in various applications is presented. The paper discusses the causes of internal and external size effects in the process of modifying WO3 electrochromic films using nanomaterials, in particular, GO/rGO nanomaterials.
The nerve tissue
consists of aligned
fibrous nerve bundles, in which neurons communicate and transmit information
through electrical signals. Hence, biocompatibility, oriented fibrous
structure, and electrical conductivity are key factors for the biomimetic
design of nerve scaffolds. Herein, we built a technical platform to
combine electrospinning and electrospraying for preparing a biomimetic
scaffold with conductivity and aligned fibrous structure. The highly
aligned polycaprolactone (PCL) microfibrous scaffolds with co-sprayed
collagen and conductive polypyrrole nanoparticles (PPy NPs) showed
good bioactivity, supplying a platform for exploring the effects of
topographical guidance, fiber conductivity, and its mediated external
electrical signals on neurogenesis. The results revealed that collagen-coated
highly aligned PCL microfibrous scaffold induced PC12 cells oriented
and elongated along the direction of fibers. In addition, the improved
conductivity of PPy-coated aligned fibers and its mediated external
electrical stimulation collectively contributed to the functional
expression, including elongation, gene expression, and protein expression,
of PC12 cells. We further demonstrated the potential mechanism where
the fiber conductivity and its mediated external electrical signals
resulted in the upregulation of voltage-gated calcium channel, leading
to the influx of Ca2+, thereby activating intracellular
signaling cascades, ultimately enhancing neurogenesis. This approach
provides a strategy to design aligned fibrillary scaffolds with bioactive
adhesion domains and electroconductivity for neural regeneration.
The development of reliable and effective functional materials that can be used in various technological fields and environmental conditions is one of the goals of modern nanotechnology. Heating elements’ manufacturing requires understanding the laws of heat transfer under conditions of different supply voltages, as this expands the possibilities of such materials’ application. Elastomers based on silicon-organic compounds and polyurethane modified with multi-walled carbon nanotubes (MWCNTs) were studied at various concentrations of Ni/MgO or Co-Mo/MgO and voltages (220, 250, and 300 V). It was found that an increase in voltage from 220 to 300 V leads to an initial increase in specific power on one-third followed by a subsequent decrease in a specific power when switched on again to 220 V (for −40 °C) of up to ~44%. In turn, for a polyurethane matrix, an increase in voltage to 300 V leads to an initial peak power value of ~15% and a decrease in power when switched on again by 220 V (for −40 °C) to ~36% (Ni/MgO -MWCNT). The conducted studies have shown that the use of a polyurethane matrix reduces power degradation (associated with voltage surges above 220 V) by 2.59% for Ni/MgO–based MWCNT and by 10.42% for Co-Mo/MgO. This is due to the better heat resistance of polyurethane and the structural features of the polymer and the MWCNT. The current studies allow us to take the next step in the development of functional materials for electric heating and demonstrate the safety of using heaters at a higher voltage of up to 300 V, which does not lead to their ignition, but only causes changes in electrophysical parameters.
This work represents a new approach for analyzing emission characteristics of multitip field cathodes. The approach is based on using a computerized field emission projector to investigate the behavior of the microscopic emission sites of the field cathode surface. Adsorption-desorption processes on the surface—which influence the emission current level—were investigated by tracking the individual emission sites under conditions of a sharp decrease and increase in the voltage level. An analysis of the transient process showed that emission sites with highest local currents almost do not participate in changing the overall level of emission current, but they became smaller with a decrease in the step voltage contribution of the dimmest sites. Similar dependences were obtained for rising voltage levels but with much faster transitions.
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