Effect of Monosaccharides and Disaccharides Type on Ionic Conductivity of Liquid Electrolyte Based Lithium Iodide

Liquid electrolyte was prepared by dissolving glucose, fructose, sucrose and lactose separately with different percentage of lithium iodide (10 – 35%) in aqueous solution of 1% acetic acid. Liquid electrolyte is characterized using conductivity meter to determine ionic conductivity. Computer simulations of Density Functional Theory (DFT) was used to identify the dominant functional groups on monomers such as glucose, sucrose, fructose and lactose when interact with the lithium salt by using B3LYP/6-31G ++ (d, p) basis set. The highest ionic conductivity for monosaccharide is glucose at 28.20 mS/cm while for disaccharide is lactose at 28.00 mS/cm with percentage of salt at 35 wt.%. Ionic conductivity increases when concentration of salt increase because there is an interaction between salt with functional groups of compounds. Based on computer simulations of DFT, interaction between lithium with compounds can be occurred due to negative electrostatic potential on the molecule. Electronegativity value of oxygen atom in glucose (-0.562e) and lactose (-0.567e) higher than fructose (-0.559e) and sucrose (-0.515e). Functional groups that are dominant to interact when interact with lithium salt are O-15 for glucose and O-17 for lactose due to the shorter bond length, the stronger energy attraction between functional groups with lithium

Kesan garam litium nitrat terhadap sifat elektrokimia karboksimetil kitosan

Karboksimetil kitosan menunjukkan potensi untuk digunakan sebagai polimer induk bagi aplikasi elektrolit polimer pepejal. Kesan garam litium nitrat terhadap sifat elektrokimia elektrolit polimer pepejal berasaskan karboksimetil kitosan telah dijalankan. Elektrolit polimer pepejal berasaskan karboksimetil kitosan disediakan melalui teknik pengacuan larutan dengan nisbah garam litium nitrat (LiNO3) yang berbeza. Pencirian filem telah dijalankan dengan menggunakan spektroskopi inframerah transformasi Fourier-pantulan penuh kecil (ATR-FTIR) dan Spektroskopi Impedans Elektrokimia (EIS) bagi penentuan interaksi kimia dan sifat elektrokimia polimer elektrolit tersebut. Spektrum ATR-FTIR menunjukkan ion litium cenderung untuk berinteraksi dengan kumpulan karbonil dan kumpulan ester dalam struktur karboksimetil kitosan. Kekonduksian ion tertinggi yang dicapai adalah 8.44 × 10-4 S cm-1 dengan kepekatan garam 30 bt. % LiNO3 pada suhu bilik dan 5.25 × 10-3 S cm−1 pada suhu 70°C. Filem karboksimetil kitosan-30% LiNO3 mencapai kestabilan secara elektrokimia sehingga 2.94 V. Keputusan kajian yang diperoleh menunjukkan elektrolit polimer pepejal berasaskan karboksimetil kitosan memberi satu tarikan baru bagi aplikasi bateri ion litium

Kajian Teoritik Efek Pelarut pada Coumarin untuk Aplikasi Dye Sel Surya

Dye-sensitized solar cell (DSSC) merupakan salah satu piranti penting di mana teknologi paling umum digunakan untuk mentransfer energi matahari menjadi listrik, namun efisiensinya masih relatif rendah.  Pewarna coumarin dasar memiliki potensi yang cukup tinggi untuk digunakan  di DSSC dengan sifat yang  ramah lingkungan dan mudah produksi.  Adapun tujuan penelitian ini adalah mempelajari potensial coumarin sebagai zat warna pada piranti sel surya. Langkah dasar dalam memahami perilaku mikroskopis untuk mempelajari potensial dye ini, peneliti mempelajari struktur geometris, struktur elektronik dan optik dari dye coumarin dalam pelarut menggunakan metode kerapatan fungsional atau density functional theory (DFT) dan time dependent density functional theory (TD-DFT).  Hasil penelitian menunjukkan bahwa efek pelarut pada dye coumarin dapat menstabilkan struktur coumarin.   Dengan adanya  zat pelarut dapat meningkatkan gap energi orbital dari  HOMO-LUMO,  kekuatan osilator, dan memiliki efisiensi penyerapan cahaya (LHE) yang lebih tinggi, serta pergeseran spektrum penyerapan UV ke arah sinar tampak.  Hasil ini menunjukkan bahwa pelarut memiliki sifat yang lebih baik untuk aplikasi di DSSC pada coumarin tanpa modifikasi

Effect of Citric Acid on Electrochemical Properties of Liquid Electrolytes

Effect of citric acid as plasticizer on the electrochemical properties of liquid electrolyte has been studied. Liquid electrolyte was prepared by dissolving citric acid in 1% acetic acid with presence of lithium nitrate salt. Liquid electrolyte is characterized using a conductivity meter to measure the ionic conductivity value. Computer simulation of Density Functional Theory (DFT) with B3LYP/6-31G ++ (d, p) basic set was performed to identify the dominant functional group of citric acid when interact with lithium salt. Increasing the weight of citric acid has increased the ionic conductivity up to 44.89 mS/cm with an optimum weight of 4 g, while the ionic conductivity increases up to 43.00 mS/cm when the percentage of lithium nitrate salt increases up to 30%. The ionic conductivity increases as the salt percentage increases due the interaction between salt and functional group of citric acid. Based on computer simulation of DFT,  the dominant functional group in citric acid that interact with lithium salt are carboxylic acid group which is located in the middle of the citric acid chain causing lithium ions to be more likely interact with citric acid

The effects of monosaccharides on the physico-electrochemical properties of chitosan based solid polymer electrolytes (SPEs)

Monosaccharides have shown their potential as plasticizers in solid polymer electrolytes (SPEs) due to the presence of numerous hydroxyl (OH) functioning groups. Glucose and fructose were used in this study. The effect of monosaccharides on physico-electrochemical properties of solid polymer electrolytes based on chitosan have been studied. Chitosan-based polymer electrolytes have been successfully plasticized using a solution-casting technique at six different weight percentages (0-30 wt.%). The result shows that 15 wt.% was the highest ionic conductivity achieved by both chitosan-glucose (CG) and chitosan-fructose (CF) systems. Lithium transference number (TLi +) analysis showed that CF had a high number of lithium ions compared to the CG system, with values of 0.26 and 0.14, respectively. In addition, Linear Sweep Voltammetry (LSV) analysis shows that the electrochemical stability for the CG system was 2.98 V compared to 3.20 V for the CF system. This discovery demonstrates that monosaccharides have the potential to be used as plasticizers due to the presence of several oxygen atoms in the structure, which act as a coordination site for cation interaction and can also improve the ion mobility and ionic conductivity of chitosan-based solid polymer electrolytes

Bio-based polycationic polyurethane as an ion-selective membrane for nitrate tapered optical fiber sensors

A novel bio-based polycationic polyurethane as an ion-selective membrane for nitrate sensing was successfully developed. In this work, the intermolecular interactions at active polymeric sites play a primary role in selective nitrate-ion detection. From the experiment, FTIR shows a significant shift from 1543 cm−1 to 1548 cm−1 in N-H bending, indicating that intermolecular interactions occur between the polycationic polyurethane and nitrate. AFM shows that the surface roughness of the polycationic polyurethane decreases from 95.7 nm to 12.2 nm after immersion in nitrate solution. Meanwhile, FESEM images show that the bright area, which represents the hard segment of polycationic polyurethane, decreases after immersion, indicating that the nitrate is interacting with the hard segment of the polycationic polyurethane via intermolecular interaction. Furthermore, EIS shows that the conductivity increases from 2.84 × 10−11 to 5.34 × 10−11 S cm−1 after ion exchange occurs between the iodide and nitrate on the polycationic polyurethane. To assess the sensing performance, the sensor probe is fabricated by coating the polycationic polyurethane thin film on the tapered region of an optical fiber. Rapid detection, good repeatability, and a sensitivity of 5.94 × 10−2µW/ppm are obtained for nitrate detection using the above bio-based-sensing material. The selectivity study also shows that the sensing material possesses high affinity toward the nitrate ion

A quinoline-based fluorescent labelling for zinc detection and DFT calculations

8-carboxamidoquinoline derivatives were gradually investigated as zinc’s label in resolving weak water solubility, poor membrane permeability, and difficulty measuring free Zn2+ ion in cells quantitatively. The potential of 2-oxo-2-(quinolin-8-ylamino)acid (OQAA) as zinc’s label was prepared and characterized spectroscopically. Theoretical and experimental data of OQAA were compared and discussed. The optimized molecular structure, molecular orbital of HOMO-LUMO, energy band gaps, and molecular electrostatic potential (MEP) of OQAA were carried out using the DFT method with Becke-3-Parameter-Lee-Yang-Parr (B3LYP) and 6-31G(d,p) basis set. The intermolecular interaction energy of OQAA-Zn is calculated by using the hybrid method of GEN with a basis set of LANL2DZ for Zn2+ ion and DFT/6-31G(d,p) for OQAA ligand. OQAA exhibited remarkable and excellent fluorescence enhancement selective and qualitatively only for Zn2+ than other metal cations tested (Fe2+, Cu2+, Co2+, Ni2+, Hg2+, Cd2+) under a long wavelength. Job’s plot and 1H NMR titrations indicate OQAA-Zn2+ has a binding ratio at 1:1 stoichiometry (M1L1). Substantial shifting of amide N-H proton to higher chemical shift and intensity of the proton peak of N-H amide decrease abruptly implies that Zn2+ is binding to an amide. These changes confirmed interactions among the ligand OQAA and metal Zn2+ ion. As a result of the benefits discussed, OQAA could effectively and selectively optimize and fabricate for Zn2+ sensors

Fabrication of Aromatic Polyimide Films Derived from Diisocyanate with Fluorinated Dianhydride

The range of available structure combinations to synthesize polyimide (PI) makes it technically possible to have various universal methods of producing PI film. The molecular design, in which monomers used to synthesize PI are carefully selected to meet specific application requirements as it influenced the properties of PI films. This study aimed to outline the approach for film fabrication through the casting of highly organo-soluble polyimide derived from 4,4’-methylene diphenyl diisocyanate (MDI) with 4,4’-(hexafluoroisopropylidene) diphtalic anhydride (6FDA) in different heating treatments. The solution drop amount was tested in order to control the films colour uniformity. A flexible and less crystalline MDI-6FDA film with an average thickness of 93 μm was successfully developed with a tensile strength of up to 57 MPa and an elongation at break of 5%. The resulting MDI-6FDA film also demonstrated good optical transparency (T500 = 69%) with a cut-off wavelength at 371 nm and high thermal resistance (T5 = 574 ℃) with a Tg temperature of up to 238 ℃. The obtained film also shows good chemical resistance in methanol, ethanol, isopropanol, and tetrahydrofuran solvents. These outcomes serve as a guideline for the fabrication of polyimide films specifically derived from diisocyanate and dianhydride, with the potential advantages to be used in optical applications.</p

Fabrication of aromatic polyimide films derived from diisocyanate with fluorinated dianhydride

The range of available structure combinations to synthesize polyimide (PI) makes it technically possible to have various universal methods of producing PI film. The molecular design, in which monomers used to synthesize PI are carefully selected to meet specific application requirements as it influenced the properties of PI films. This study aimed to outline the approach for film fabrication through the casting of highly organo-soluble polyimide derived from 4,4’-methylene diphenyl diisocyanate (MDI) with 4,4’-(hexafluoroisopropylidene) diphtalic anhydride (6FDA) in different heating treatments. The solution drop amount was tested in order to control the films colour uniformity. A flexible and less crystalline MDI-6FDA film with an average thickness of 9