scholarly journals PHYSICO-CHEMICAL PROPERTIES OF ELECTROCHROMIC COMPLEX TUNGSTEN OXIDES

2021 ◽  
pp. 421-429
Author(s):  
Борис Магометович Хуболов
Keyword(s):  
Electronic Structure ◽  
Condensed System ◽  
Tungsten Bronze ◽  
Chemical Properties ◽  
Electrochromic Devices ◽  
Strong Electron ◽  
Tungsten Oxides ◽  
Physico Chemical ◽  
Starting Point ◽  
Condensed Systems

Приведён краткий обзор проблемы электрохромизма в неупорядоченных тонких пленках сложных оксидов вольфрама на основе экспериментальных результатов, опубликованных ранее. Рассмотрены проблемы ионно-электронного упорядочения в сложных оксидах вольфрама MWO ( M = Na, K и x = 0,3), их взаимосвязь с динамикой процесса электрохромного окрашивания в этих конденсированных системах. Рассмотрены возможные пути решения обозначенных проблем. Отправной точкой нашего похода к исследованию электрохромизма и разработки физических основ технологии электрохромных устройств явился отказ от общепринятого электрохимического рассмотрения этого явления. Мы убеждены в том, что электрохромный эффект является чисто твердотельным эффектом, происходящим в конденсированной системе с сильной электронной корреляцией. Электронная структура твердого тела, имеющаяся на границе раздела твердое тело-электролит в значительной степени, управляет характером и скоростью реакций, которые протекают на его поверхности. В случае окислов роль, которую играет электронная структура особенно сложна. Все изложенное указывает на необходимость рассмотрения влияния глубоких уровней в объеме оксидной вольфрамовой бронзы и на ее поверхности, граничащей с электролитом на процесс электрохромного окрашивания. A brief review of the problem of electrochromism in disordered thin films of complex tungsten oxides is given on the basis of experimental results published earlier. The problems of the ion-electron ordering in complex tungsten oxides MWO (M = Na or K and x = 0,3) are regarded as well as their relationship with the dynamics of the process of electrochromic coloring in these condensed systems. Possible ways of solving the indicated problems are considered. The starting point of our campaign to study the electrochromism and to develop the physical grounds of the technology of electrochromic devices was the rejection of the generally accepted electrochemical consideration of this phenomenon. We are convinced that the electrochromic effect is a purely solid-state one occurring in a condensed system with a strong electron correlation. The electronic structure of a solid at the solid-electrolyte interface largely controls the nature and rate of reactions that take place on its surface. In the case of oxides, the role played by the electronic structure is particularly complex. All of the above indicates the need to consider the effect of deep levels in the bulk of the oxide tungsten bronze and on its surface, bordering the electrolyte, on the process of electrochromic coloring.

Symmetric naphthalenediimidequaterthiophenes for electropolymerized electrochromic thin films

2015 ◽  
Vol 3 (23) ◽  
pp. 5985-5994 ◽  
Author(s):  
V. Figà ◽  
C. Chiappara ◽  
F. Ferrante ◽  
M. P. Casaletto ◽  
F. Principato ◽  
...  
Keyword(s):  
Thin Films ◽  
Chemical Properties ◽  
Electrochromic Devices ◽  
Coloration Efficiency ◽  
Physico Chemical ◽  
Donor Acceptor

Novel electropolymerized copolymers with a controlled donor/acceptor ratio obtained from symmetric naphthalenediimidequaterthiophene showed prominent physico-chemical properties and high coloration efficiency in electrochromic devices.

scholarly journals How Substitution Combines with Non-Covalent Interactions to Modulate 1,4-Naphthoquinone and Its Derivatives Molecular Features—Multifactor Studies

2021 ◽  
Vol 22 (19) ◽  
pp. 10357
Author(s):  
Michał Pocheć ◽  
Karol Kułacz ◽  
Jarosław J. Panek ◽  
Aneta Jezierska
Keyword(s):  
Electronic Structure ◽  
Density Functional ◽  
Parent Compound ◽  
Chemical Properties ◽  
Intramolecular Hydrogen Bonding ◽  
Cooperative Effects ◽  
Molecular Features ◽  
Physico Chemical ◽  
Donor And Acceptor ◽  
Intramolecular Hydrogen

Substitution is well-known to modulate the physico-chemical properties of molecules. In this study, a combined, multifactor approach was employed to determine a plethora of substitution patterns using –Br and –O-H in 1,4-naphthoquinone and its derivatives. On the basis of classical Density Functional Theory (DFT), 25 models divided into three groups were developed. The first group contains 1,4-naphthoquinone and its derivatives substituted only by –Br. The second group consists of compounds substituted by –Br and one –O-H group. As a result of the substitution, an intramolecular hydrogen bond was formed. The third group also contains –Br as a substituent, but two –O-H groups were introduced and two intramolecular hydrogen bonds were established. The simulations were performed at the ωB97XD/6-311++G(2d,2p) level of theory. The presence of substituents influenced the electronic structure of the parent compound and its derivatives by inductive effects, but it also affected the geometry of the 2 and 3 groups, due to the intramolecular hydrogen bonding and the formation of a quasi-ring/rings. The static DFT models were applied to investigate the aromaticity changes in the fused rings based on the Harmonic Oscillator Model of Aromaticity (HOMA). The OH stretching was detected for the compounds from groups 2 and 3 and further used to find correlations with energetic parameters. The evolution of the electronic structure was analyzed using Hirshfeld atomic charges and the Substituent Active Region (cSAR) parameter. The proton reaction path was investigated to provide information on the modulation of hydrogen bridge properties by diverse substitution positions on the donor and acceptor sides. Subsequently, Car–Parrinello Molecular Dynamics (CPMD) was carried out in the double-bridged systems (group 3) to assess the cooperative effects in double –O-H-substituted systems. It was determined that the –O-H influence on the core of the molecule is more significant than that of –Br, but the latter has a major impact on the bridge dynamics. The competitive or synergic effect of two –Br substituents was found to depend on the coupling between the intramolecular hydrogen bridges. Thus, the novel mechanism of a secondary (cooperative) substituent effect was established in the double-bridged systems via DFT and CPMD results comparison, consisting of a mediation of the bromine substitutions’ influence by the cooperative proton transfer events in the hydrogen bridges.

scholarly journals Changes in the physico-chemical properties of spear and pepper mint volatile oils during storage

2019 ◽  
Author(s):  
Tamer Farouk Ahmed El-Moghazy
Keyword(s):  
Room Temperature ◽  
Steam Distillation ◽  
Chemical Properties ◽  
Volatile Oil ◽  
Research Station ◽  
Distillation Method ◽  
Volatile Oils ◽  
Physico Chemical ◽  
Starting Point ◽  
Horticultural Research

The experiment was conducted in Sabahia Horticultural Research Station, Alexandria, Egypt during the period from February 2005 until July 2007. Spear and pepper mint fields were planted late February and harvested in June 2005. The oil from the herbs was extracted by steam distillation method in a private factory in 6-October city. Then, the storage experiment was started in the middle of July 2005 and extended for two years.Dark and clear glasses, 25 ml, were filled with the oils to study the effects of the presence vs. absence of oxygen in the bottle atmosphere (half full vs. full filled bottles), dry oil vs. moisted oil (1% moisture), darkness vs. light (dark vs. clear glasses) and the effect of room temperature vs. low temperature (4oC) on the oils quality during storage. Each treatment was represented by 3 bottles, used once only in each sampling every three months for 9 times lasted for 24 months, June 2007, including the starting point samples. Storing either spear mint volatile oil or pepper mint volatile oil dry, away of air, in dark and placed in a refrigerator is recommended to keep the oils quality in good status. The active compounds will be remained in the acceptable levels and retard it far from spoilage for longer time, it might reach 24 months.

scholarly journals The risk of liquid wood degradation under the influence of marine factors

2019 ◽  
Vol 290 ◽  
pp. 12012
Author(s):  
Mihaela Luminita Barhalescu ◽  
Simona Ghita ◽  
Tudor-Cristian Petrescu
Keyword(s):  
Electric Conductivity ◽  
Renewable Resources ◽  
Chemical Properties ◽  
External Factors ◽  
Wood Degradation ◽  
Biofilm Growth ◽  
Physico Chemical ◽  
Starting Point ◽  
Biocomposite Material

A case study was performed, concerning the behavior and degradation of a polymeric biocomposite material – “liquid wood”. This material is biodegradable and it is obtained from renewable resources. Three presentation forms – Arbofill Fichte, Arboform F45 and Arboblend V2, were subjected to the action of external factors present in a marine environment. The results pertaining to the change in the physico – chemical properties of “liquid wood” when subjected to the action of seawater and seawater microorganisms, with significant – but nevertheless positive – consequences upon the environment. The material exhibits good performance after the surface and mass stabilization – due to water, C, Na, Cl and O absorption. As such – due to the emergence of a protective organic biofilm – growth of microorganisms significantly decreases and electric conductivity increases. This case study may be viewed as a starting point for subsequent studies of “liquid wood”.

ChemInform Abstract: Synthesis, Electronic Structure, and Physico-Chemical Properties of Pyrazolo(1,2-a)pyridazinium Perchlorates.

ChemInform ◽  
2010 ◽  
Vol 23 (41) ◽  
pp. no-no
Author(s):  
V. N. VOSHCHULA ◽  
YU. B. VYSOTSKII ◽  
V. J. SERAYA ◽  
N. T. NOVIKOVA ◽  
R. YA. MUSHII ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Chemical Properties ◽  
Physico Chemical

Decoration of specific sites on freeze-fractured membranes

1978 ◽  
Vol 36 (2) ◽  
pp. 140-141
Author(s):  
H. Gross ◽  
H. Moor
Keyword(s):  
Pure Water ◽  
Freeze Fracture ◽  
Chemical Properties ◽  
Surface Forces ◽  
Sulfate Pentahydrate ◽  
Copper Sulfate Pentahydrate ◽  
Physico Chemical ◽  
Water Of Hydration ◽  
Small Container ◽  
Binding Forces

Fracturing under ultrahigh vacuum (UHV, p ≤ 10-9 Torr) produces membrane fracture faces devoid of contamination. Such clean surfaces are a prerequisite foe studies of interactions between condensing molecules is possible and surface forces are unequally distributed, the condensate will accumulate at places with high binding forces; crystallites will arise which may be useful a probes for surface sites with specific physico-chemical properties. Specific “decoration” with crystallites can be achieved nby exposing membrane fracture faces to water vopour. A device was developed which enables the production of pure water vapour and the controlled variation of its partial pressure in an UHV freeze-fracture apparatus (Fig.1a). Under vaccum (≤ 10-3 Torr), small container filled with copper-sulfate-pentahydrate is heated with a heating coil, with the temperature controlled by means of a thermocouple. The water of hydration thereby released enters a storage vessel.

Sign in / Sign up

Export Citation Format

Share Document