Electrochromic and non-volatile bistable resistive switching behaviour of acid-doped poly(triphenylamine ether)s

2017 ◽  
Vol 46 (3) ◽  
pp. 218-225
Author(s):  
Benfu Wang ◽  
Decai Ren ◽  
Qian Zhang ◽  
Xuduo Bai ◽  
Xiankai Jiang
Keyword(s):  
Resistive Switching ◽  
Electrolyte Solution ◽  
Coupling Reaction ◽  
Molar Ratio ◽  
Alkyl Ether ◽  
Aryl Ether ◽  
Neutral State ◽  
Content Type ◽  
Light Blue ◽  
Switching Behaviour

Purpose This paper aims to investigate the electrochromic (EC) properties of poly(triphenylamine alkyl ether) and poly(triphenylamine aryl ether) in two different electrolyte solution to study the resistive switching behaviour of acid-doped poly(triphenylamine alkyl ether). Design/methodology_appach By Buchwald–Hartwig coupling reaction, two novel poly[N-p-phenoxy-N-[4-[2-(2-methoxyethoxy)ethoxy]ethoxy]triphenylamineandpoly[N,N-bis(4-phenoxy)]triphenylamine were synthesized from 4-phenoxyaniline and two dibromo aromatic compounds, 1,2-bis[β,β′-(p-bromophenoxy)ethoxy]ethane and bis(4-bromophenyl) ether. Findings Poly(triphenylamine alkyl ether) displayed excellent EC characteristics, with a coloration change from a colourless neutral state to light blue and red oxidized states, while poly(triphenylamine aryl ether) showed coloration a change from a colourless neutral state to light blue oxidized state in tetrabutylammonium perchlorate electrolyte solution. Moreover, p-toluenesulfonic acid-doped poly(triphenylamine alkyl ether) exhibited a non-volatile bistable resistive switching behaviour with a high high-conductivity/low-conductivity ratio of up to 104, long retention time exceeding 2.5 × 103 s and the switching threshold voltage was also lower than −2V. Research limitations/implications In this paper, the non-volatile bistable resistive switching behaviour of acid-dopedpoly(triphenylamine alkyl ether) was in accordance with the molar ratio of 1:1. The effects of different molar ratios remained to be studied. Practical implications Poly(triphenylamine ether)s may find optoelectronic applications as new EC and resistive switching materials. Originality/value The effects of alkyl and aryl ether structures in the main chain on the EC and resistive switching behaviour of triphenylamine unit have not yet been reported.

scholarly journals Grafting of (3-Chloropropyl)-Trimethoxy Silane on Halloysite Nanotubes Surface

2021 ◽  
Vol 11 (12) ◽  
pp. 5534
Author(s):  
Asmaa M. Abu El-Soad ◽  
Giuseppe Lazzara ◽  
Alexander V. Pestov ◽  
Daria P. Tambasova ◽  
Denis O. Antonov ◽  
...  
Keyword(s):  
Active Site ◽  
Chemical Engineering ◽  
Coupling Reaction ◽  
Ammonium Hydroxide ◽  
Halloysite Nanotubes ◽  
Chemical Activity ◽  
Molar Ratio ◽  
New Materials ◽  
Experimental Conditions ◽  
Trimethoxy Silane

Modified halloysite nanotubes (HNTs-Cl) were synthesized by a coupling reaction with (3-chloropropyl) trimethoxysilane (CPTMS). The incorporation of chloro-silane onto HNTs surface creates HNTs-Cl, which has great chemical activity and is considered a good candidate as an active site that reacts with other active molecules in order to create new materials with great applications in chemical engineering and nanotechnology. The value of this work lies in the fact that improving the degree of grafting of chloro-silane onto the HNT’s surface has been accomplished by incorporation of HNTs with CPTMS under different experimental conditions. Many parameters, such as the dispersing media, the molar ratio of HNTs/CPTMS/H2O, refluxing time, and the type of catalyst were studied. The greatest degree of grafting was accomplished by using toluene as a medium for the grafting process, with a molar ratio of HNTs/CPTMS/H2O of 1:1:3, and a refluxing time of 4 h. The addition of 7.169 mmol of triethylamine (Et3N) and 25.97 mmol of ammonium hydroxide (NH4OH) led to an increase in the degree of grafting of CPTMS onto the HNT’s surface.

Synthesis and Characterization of Poly(Aryl Ether Quinoxaline)s with Controlled Molecular Weight

2011 ◽  
Vol 391-392 ◽  
pp. 826-829
Author(s):  
Song Ya Zhang ◽  
Zhong Xiao Li ◽  
Jia Ling Pu
Keyword(s):  
Molecular Weight ◽  
Glass Transition ◽  
Strong Acid ◽  
Decomposition Temperature ◽  
Molar Ratio ◽  
Synthesis And Characterization ◽  
Aryl Ether ◽  
Good Solubility ◽  
Step Procedure

Novel poly(aryl ether quinoxaline)s (PEQs) were prepared via a two-step procedure. First, poly (ether benzil) (PEB) was synthesized by the polycondensation of 4,4’-difluorobenzil and 4,4’-isopropylidenediphenol.Then, PEB was reacted with 1,2-diaminobenzene and 4,4'-oxydibenzene-1,2-diamine to give the PEQs. The molecular weight of the PEQs could be adjusted easily by varying the molar ratio of 1,2-diaminobenzene to 4,4'-oxydibenzene-1,2-diamine. The PEQs exhibited good solubility in common organic solvents such as NMP, DMAc, DMF, cyclohexanone and chloroform. In addition, the PEQs also had high glass transition (Tg) temperatures and good thermal properties, with an initial thermal decomposition temperature above 475 oC and glass transition temperatures above 210 oC. They also exhibited excellent resistance to strong acid and alkali.

Switching behaviour in activity-based working environments: an exploration of the reasons and influencing factors

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Eunji Häne ◽  
Lukas Windlinger
Keyword(s):  
Influencing Factors ◽  
Design Methodology ◽  
Online Survey ◽  
Facility Management ◽  
Switching Frequency ◽  
Push Factors ◽  
Content Type ◽  
Activity Settings ◽  
Working Environments ◽  
Switching Behaviour

Purpose A tendency that employees do not frequently switch between different activity settings was reported in previous studies, which are opposed to underlying assumptions of activity-based working (ABW) offices. Although ABW is increasingly becoming a standard office concept, employees’ switching behaviour has not been studied in depth. This study aims to understand employees’ switching behaviour by identifying reasons (not) to switch and various influencing factors of switching behaviour. Design/methodology/approach An online survey was conducted across Switzerland and Belgium, and 124 respondents participated in the questionnaire. The mismatch model was developed to examine whether the misfit between either activity or preference and work environment leads to switching to another place in the office. Findings Results show that most of the respondents switch multiple times a day, which runs counter to the previous studies. Furthermore, this study presented clear evidence that mandatory switching frequency is independent of various factors presented in the study, indicating that the distinction between mandatory and voluntary switching is valid. Besides, results identified privacy, acoustics, distraction, proximity to team/colleagues as reasons to switch and as reasons not to switch, place preference/attachment, proximity to the team were determined. Originality/value This study contributed to better understanding switching behaviour by defining, distinguishing switching behaviour, identifying reasons (not) to switch and influencing factors of switching frequency. In addition, this study compared the misfit between activity and environment and the misfit between preference and environment as push factors leading to switching behaviour. These findings can provide more knowledge of switching behaviour to workplace or facility management practitioners.

scholarly journals Crystal structure of 1,4-bis[5-(2-methoxyphenyl)-2H-tetrazol-2-yl]butane

2019 ◽  
Vol 75 (12) ◽  
pp. 1844-1847
Author(s):  
Young Min Byun ◽  
Farwa Ume ◽  
Ji Yeon Ryu ◽  
Junseong Lee ◽  
Hyoung-Ryun Park
Keyword(s):  
Title Compound ◽  
Methoxy Group ◽  
Coupling Reaction ◽  
Major Product ◽  
Molar Ratio ◽  
Dihedral Angles ◽  
X Ray ◽  
Compound C ◽  
Crystallographic Study ◽  
Centrosymmetric Dimers

The title compound, C20H22N8O2, was synthesized by the coupling reaction of a sodium tetrazolate salt and dibromobutane in a molar ratio of 2:1. The reaction can produce several possible regioisomers and the title compound was separated as the major product. The X-ray crystallographic study confirmed that the title compound crystallizes in the monoclinic P21/c space group and possesses a bridging butylene group that connects two identical phenyl tetrazole moieties. The butylene group is attached not to the first but the second nitrogen atoms of both tetrazole rings. The dihedral angles between the phenyl groups and the adjacent tetrazolyl rings are 5.32 (6) and 15.37 (7)°. In the crystal, the molecules form centrosymmetric dimers through C—H...O hydrogen bonds between a C—H group of the butylene linker and the O atom of a methoxy group.

Alkalibacterium gilvum sp. nov., slightly halophilic and alkaliphilic lactic acid bacterium isolated from soft and semi-hard cheeses

2013 ◽  
Vol 63 (Pt_4) ◽  
pp. 1471-1478 ◽  
Author(s):  
Morio Ishikawa ◽  
Kazuhide Yamasato ◽  
Kayo Kodama ◽  
Hinako Yasuda ◽  
Mioko Matsuyama ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Sequence Similarity ◽  
16S Rrna Genes ◽  
Rrna Genes ◽  
Molar Ratio ◽  
Phylogenetic Position ◽  
Growth Responses ◽  
Cultivation Conditions ◽  
Content Type ◽  
Link Type

Nine novel strains of halophilic and alkaliphilic lactic acid bacteria isolated from European soft and semi-hard cheeses by using a saline, alkaline medium (7 % NaCl, pH 9.5) were taxonomically characterized. The isolates were Gram-stain-positive, non-sporulating and non-motile. They lacked catalase and quinones. Under anaerobic cultivation conditions, lactate was produced from d-glucose with the production of formate, acetate and ethanol with a molar ratio of approximately 2 : 1 : 1. Under aerobic cultivation conditions, acetate and lactate were produced from d-glucose. The isolates were slightly halophilic, highly halotolerant and alkaliphilic. The optimum NaCl concentration for growth ranged between 2.0 % and 5.0 % (w/v), with a growth range of 0–1 % to 15–17.5 %. The optimum pH for growth ranged between 8.5 and 9.5, with a growth range of 7.0–7.5 to 9.5–10.0. Comparative sequence analysis of the 16S rRNA genes revealed that the isolates occupied a phylogenetic position within the genus Alkalibacterium , showing the highest sequence similarity (98.2 %) to Alkalibacterium kapii T22-1-2T. The isolates constituted a single genomic species with DNA–DNA hybridization values of 79–100 % among the isolates and <29 % between the isolates and other members of the genus Alkalibacterium , from which the isolates were different in motility and flagellation, growth responses to NaCl concentrations and pH, and profiles of sugar fermentation. The DNA G+C contents were between 36.0 and 37.6 mol%. The cell-wall peptidoglycan was type A4β, Orn-d-Asp. The major components of cellular fatty acids were C14 : 0, C16 : 0 and C16 : 1ω9c. Based on the phenotypic characteristics and genetic distinctness, the isolates are classified as a novel species within the genus Alkalibacterium , for which the name Alkalibacterium gilvum sp. nov. is proposed. The type strain is 3AD-1T ( = DSM 25751T = JCM 18271T).

scholarly journals Reversible resistive switching behaviour in CVD grown, large area MoOx

Nanoscale ◽  
2018 ◽  
Vol 10 (42) ◽  
pp. 19711-19719 ◽  
Author(s):  
Fahmida Rahman ◽  
Taimur Ahmed ◽  
Sumeet Walia ◽  
Edwin Mayes ◽  
Sharath Sriram ◽  
...  
Keyword(s):  
Resistive Switching ◽  
Memory Devices ◽  
Large Area ◽  
Switching Behaviour

Reversible resistive switching behaviour is observed in MoOx memory devices, at relatively low set/reset voltages, with switching ratios exceeding 103.

Resistive Switching Memory based on Silver-doped Chitosan Thin Films

MRS Advances ◽  
2018 ◽  
Vol 3 (33) ◽  
pp. 1943-1948 ◽  
Author(s):  
C. Strobel ◽  
T. Sandner ◽  
S. Strehle
Keyword(s):  
Thin Films ◽  
Resistive Switching ◽  
Tin Oxide ◽  
Bottom Electrode ◽  
Low Cost ◽  
Memory Devices ◽  
Neuromorphic Computing ◽  
Resistive Switching Memory ◽  
Switching Behaviour ◽  
Switching Memory

AbstractMemristors represent an intriguing two-terminal device strategy potentially able to replace conventional memory devices as well as to support neuromorphic computing architectures. Here, we present the resistive switching behaviour of the sustainable and low-cost biopolymer chitosan, which can be extracted from natural chitin present for instance in crab exoskeletons. The biopolymer films were doped with Ag ions in varying concentrations and sandwiched between a bottom electrode such as fluorinated-tin-oxide and a silver top electrode. Silver-doped devices showed an overall promising resistive switching behaviour for doping concentrations between 0.5 to 1 wt% AgNO3. As bottom electrode fluorinated-tin-oxide, nickel, silver and titanium were studied and multiple write and erase cycles were recorded. However, the overall reproducibility and stability are still insufficient to support broader applicability.

A solution processed metal–oxo cluster for rewritable resistive memory devices

2019 ◽  
Vol 7 (4) ◽  
pp. 843-852 ◽  
Author(s):  
Kui Zhou ◽  
Guanglong Ding ◽  
Chen Zhang ◽  
Ziyu Lv ◽  
Shenghuang Luo ◽  
...  
Keyword(s):  
Activation Energy ◽  
Resistive Switching ◽  
Memory Device ◽  
Memory Devices ◽  
Resistive Memory ◽  
Solution Processed ◽  
Switching Behaviour

A memory device based on metal–oxo cluster-assembled materials demonstrates a redox-based resistive switching behaviour which is correlated with the migration of hydroxide ions with low activation energy.

scholarly journals Cellular Stoichiometry of Chemotaxis Proteins in Sinorhizobium meliloti

2020 ◽  
Vol 202 (14) ◽  
Author(s):  
Timofey D. Arapov ◽  
Rafael Castañeda Saldaña ◽  
Amanda L. Sebastian ◽  
W. Keith Ray ◽  
Richard F. Helm ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Bacillus Subtilis ◽  
Sinorhizobium Meliloti ◽  
Response Regulator ◽  
Bacterial Chemotaxis ◽  
Adaptor Proteins ◽  
Molar Ratio ◽  
Content Type ◽  
Chemotaxis Proteins ◽  
Chemotaxis System

ABSTRACT Chemotaxis systems enable microbes to sense their immediate environment, moving toward beneficial stimuli and away from those that are harmful. In an effort to better understand the chemotaxis system of Sinorhizobium meliloti, a symbiont of the legume alfalfa, the cellular stoichiometries of all ten chemotaxis proteins in S. meliloti were determined. A combination of quantitative immunoblot and mass spectrometry revealed that the protein stoichiometries in S. meliloti varied greatly from those in Escherichia coli and Bacillus subtilis. To compare protein ratios to other systems, values were normalized to the central kinase CheA. All S. meliloti chemotaxis proteins exhibited increased ratios to various degrees. The 10-fold higher molar ratio of adaptor proteins CheW1 and CheW2 to CheA might result in the formation of rings in the chemotaxis array that consist of only CheW instead of CheA and CheW in a 1:1 ratio. We hypothesize that the higher ratio of CheA to the main response regulator CheY2 is a consequence of the speed-variable motor in S. meliloti, instead of a switch-type motor. Similarly, proteins involved in signal termination are far more abundant in S. meliloti, which utilizes a phosphate sink mechanism based on CheA retrophosphorylation to inactivate the motor response regulator versus CheZ-catalyzed dephosphorylation as in E. coli and B. subtilis. Finally, the abundance of CheB and CheR, which regulate chemoreceptor methylation, was increased compared to CheA, indicative of variations in the adaptation system of S. meliloti. Collectively, these results mark significant differences in the composition of bacterial chemotaxis systems. IMPORTANCE The symbiotic soil bacterium Sinorhizobium meliloti contributes greatly to host-plant growth by fixing atmospheric nitrogen. The provision of nitrogen as ammonium by S. meliloti leads to increased biomass production of its legume host alfalfa and diminishes the use of environmentally harmful chemical fertilizers. To better understand the role of chemotaxis in host-microbe interaction, a comprehensive catalogue of the bacterial chemotaxis system is vital, including its composition, function, and regulation. The stoichiometry of chemotaxis proteins in S. meliloti has very few similarities to the systems in Escherichia coli and Bacillus subtilis. In addition, total amounts of proteins are significantly lower. S. meliloti exhibits a chemotaxis system distinct from known models by incorporating new proteins as exemplified by the phosphate sink mechanism.

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