scholarly journals Electrospun Nickel Manganite (NiMn2O4) Nanocrystalline Fibers for Humidity and Temperature Sensing

Sensors ◽  
2021 ◽  
Vol 21 (13) ◽  
pp. 4357
Author(s):  
Milena P. Dojcinovic ◽  
Zorka Z. Vasiljevic ◽  
Jugoslav B. Krstic ◽  
Jelena D. Vujancevic ◽  
Smilja Markovic ◽  
...  

Nickel manganite nanocrystalline fibers were obtained by electrospinning and subsequent calcination at 400 °C. As-spun fibers were characterized by TG/DTA, Scanning Electron Microscopy and FT-IR spectroscopy analysis. X-ray diffraction and FT-IR spectroscopy analysis confirmed the formation of nickel manganite with a cubic spinel structure, while N2 physisorption at 77 K enabled determination of the BET specific surface area as 25.3 m2/g and (BJH) mesopore volume as 21.5 m2/g. The material constant (B) of the nanocrystalline nickel manganite fibers applied by drop-casting on test interdigitated electrodes on alumina substrate, dried at room temperature, was determined as 4379 K in the 20–50 °C temperature range and a temperature sensitivity of −4.95%/K at room temperature (25 °C). The change of impedance with relative humidity was monitored at 25 and 50 °C for a relative humidity (RH) change of 40 to 90% in the 42 Hzπ1 MHz frequency range. At 100 Hz and 25 °C, the sensitivity of 327.36 ± 80.12 kΩ/%RH was determined, showing that nickel manganite obtained by electrospinning has potential as a multifunctional material for combined humidity and temperature sensing.

2020 ◽  
Vol 1 (4) ◽  
pp. 22-25
Author(s):  
Azwan Morni

This study reports a green method for the synthesis of gold nanoparticles (AuNPs) using the aqueous extract of Salix aegyptiaca extract. The effects of gold salt concentration, extract concentration and extract quantity were investigated on nanoparticles synthesis. Novel methods of ideally synthesizing AuNPs are thus thought that are formed at ambient temperatures, neutral pH, low costs and environmentally friendly fashion. AuNPs were characterized with different techniques such as UV–vis spectroscopy, FT-IR spectroscopy, X-ray diffraction, and TEM. FT-IR spectroscopy revealed that gold nanoparticles were functionalized with biomolecules that have primary carbonyl group, -OH groups and other stabilizing functional groups. TEM experiments showed that these nanoparticles are formed with various shapes and X-ray diffraction pattern showed high purity and face centered cubic structure of AuNPs. For electrochemical properties of AuNPs, a modified glassy carbon electrode using AuNPs (AuNPs/GCE) was investigated. The results show that electronic transmission rate between the modified electrode and [Fe (CN)6]3-/4- increased.


2016 ◽  
Vol 71 (1) ◽  
pp. 81-84 ◽  
Author(s):  
Eugen Weisheim ◽  
Hans-Georg Stammler ◽  
Norbert W. Mitzel

AbstractThe reaction of 1,3,5-triethynyl-1,3,5-trimethyl- 1,3,5-trisilacyclohexane with (dimethylamino)trimethylstannane afforded 1,3,5-tris[(trimethylstannyl)ethynyl]- 1,3,5-trimethyl-1,3,5-trisilacyclohexane with tin-functionalised ethynyl groups. The compound was characterized by single-crystal X-ray diffraction, elemental analysis, mass spectrometry, NMR and FT-IR spectroscopy.


2012 ◽  
Vol 1 (1) ◽  
pp. 5-9
Author(s):  
Anastasia Wulan Pratidina Swasono ◽  
Putri Dei Elvarosa Sianturi ◽  
Zuhrina Masyithah

Alkyl polyglicoside (APG) is an enviromentally friendly product  non-ionic surfactact and  biodegradable product that can be obtained by reacting glucose and fatty alcohol. The purpose of this study was to know the manufacture of surfactant alkyl polyglicoside by using glucose and dodecanol, and also to know the effect of catalyst concentration and molar ratio glucose  and dodecanol: 1:1; 1:2: 2:1 (mol/mol), catalyst consentration of hydrochloric acid: 0.3 M; 0,4 M; 0,5 M; 0,6 M at temperature 100 0C. The analysis in this research using FT-IR spectroscopy, analysis of surface tension (Critical Micelle Concentration) and HLB values ​​(Hidrophylic-Lipophylic Balance). The best catalyst concentration at synthesis of alkyl polyglicoside is 0.6 M, the largest surface tension (CMC) at ratio glucose and dodecanol 2:1 is 70.7945% and the highest HLB value is 7.31 in comparison of glucose and dodecanol 2:1.


2020 ◽  
Vol 76 (7) ◽  
pp. 690-694
Author(s):  
Qianjun Deng ◽  
Jiming Wang ◽  
Guangzhao Li ◽  
Shuhua Zhang

A new ionic pentanuclear FeIII cluster, namely, triethylazanium tetrakis(μ2-5-amino-1,2,3,4-tetrazolido)tetrakis(μ3-4-chloro-2-{[(1H-tetrazol-1-id-5-yl)imino]methyl}phenolato)di-μ3-oxido-pentairon(III) acetonitrile monosolvate monohydrate, (C6H16N)[Fe5(C8H4ClN5O)4(CH2N5)4O2]·CH3CN·H2O, was synthesized using microvial synthesis methods and characterized by elemental analysis, FT–IR spectroscopy, single-crystal X-ray diffraction and thermogravimetric analysis. Magnetic studies reveal that the complex displays dominant antiferromagnetic intracluster interactions between the FeIII ions through the μ3-oxide bridges.


2018 ◽  
Vol 74 (11) ◽  
pp. 1390-1394 ◽  
Author(s):  
Rami Al-Oweini ◽  
Bassem S. Bassil ◽  
Marwa Itani ◽  
Dilara Börte Emiroğlu ◽  
Ulrich Kortz

Interaction of the mixed-valent 12-manganese coordination complex [MnIII 8MnIV 4O12(CH3COO)16(H2O)4] with the lacunary 9-tungstoarsenate(V) [A-α-AsW9O34]9− resulted in the 10-manganese(III/IV)-containing 36-tungsto-4-arsenate(V), [MnIII 6MnIV 4O4(OH)12(H2O)12(A-β-AsW9O34)4]22− (1). Polyanion 1 was isolated as a hydrated mixed potassium–sodium salt, K14Na8[MnIII 6MnIV 4O4(OH)12(H2O)12(A-β-AsW9O34)4]·104H2O, which crystallizes in the orthorhombic space group Pbcn and was characterized by FT–IR spectroscopy and single-crystal X-ray diffraction, as well as elemental and thermogravimetric analyses. The title polyanion contains a unique [MnIII 6MnIV 4O4(OH)12(H2O)12]14+ core stabilized within the 36-tungsto-4-arsenate(V) framework.


RSC Advances ◽  
2019 ◽  
Vol 9 (59) ◽  
pp. 34567-34580 ◽  
Author(s):  
Abida Ashraf ◽  
Muhammad Khalid ◽  
Muhammad Nawaz Tahir ◽  
Muhammad Yaqub ◽  
Muhammad Moazzam Naseer ◽  
...  

The chemical structures of the title compounds were ascertained by spectral techniques including 1H, 13C NMR, UV-vis and FT-IR spectroscopy as well as single-crystal X-ray diffraction, and DFT computation adopted to analyze the electronic structure.


2019 ◽  
Vol 75 (4) ◽  
pp. 388-397 ◽  
Author(s):  
Sevim Hamamci Alisir ◽  
Necmi Dege ◽  
Recep Tapramaz

Three new diclofenac-based copper(II) complexes, namely tetrakis{μ-2-[2-(2,6-dichloroanilino)phenyl]acetato-κ2 O:O′}bis(methanol-κO)copper(II), [Cu2(μ-dicl)4(CH3OH)2] (1), bis{2-[2-(2,6-dichloroanilino)phenyl]acetato-κ2 O,O′}bis(1-vinyl-1H-imidazole-κN 3)copper(II), [Cu(dicl)2(vim)2] (2), and bis{2-[2-(2,6-dichloroanilino)phenyl]acetato-κ2 O,O′}bis(1H-imidazole-κN 3)copper(II), [Cu(dicl)2(im)2] (3) [dicl is diclofenac (C14H10Cl2NO2), vim is 1-vinylimidazole (C5H6N2) and im is imidazole (C3H4N2)], have been synthesized and characterized by elemental analysis, FT–IR spectroscopy, thermal analysis and single-crystal X-ray diffraction. X-ray diffraction analysis shows that complex 1 consists of dimeric units in which the dicl ligand exhibits a bidentate syn,syn-μ2 coordination mode linking two copper(II) centres. Complexes 2 and 3 have mononuclear units with the general formula [Cu(dicl)2 L 2] (L is vim or im) in which the CuII ions are octahedrally coordinated by two L and two dicl chelating ligands. The L and dicl ligands both occupy the trans positions of the coordination octahedron. The different coordination modes of dicl in the title complexes were revealed by Fourier transform IR (FT–IR) spectroscopy. The spin matching between the copper(II) centres in the dimeric [Cu2(μ-dicl)4(CH3OH)2] units was also confirmed by magnetic data to be lower than the spin-only value and electron paramagnetic resonance (EPR) spectra. The thermal properties of the complexes were investigated by thermogravimetric (TG) and differential thermal analysis (DTA) techniques.


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