scholarly journals Systematic Characterization of DMPC/DHPC Self-Assemblies and Their Phase Behaviors in Aqueous Solution

2018 ◽  
Vol 2 (4) ◽  
pp. 73 ◽  
Author(s):  
Shogo Taguchi ◽  
Keishi Suga ◽  
Keita Hayashi ◽  
Yukihiro Okamoto ◽  
Ho-Sup Jung ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Membrane Properties ◽  
Morphological Properties ◽  
Molar Ratio ◽  
Region I ◽  
Gel Phase ◽  
Phase Behaviors ◽  
Region Ii ◽  
Interfacial Membrane

Self-assemblies composed of 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) and 1,2-dihexanoyl-sn-glycero-3-phosphocholine (DHPC) form several kinds of structures, such as vesicle, micelle, and bicelle. Their morphological properties have been studied widely, but their interfacial membrane properties have not been adequately investigated. Herein, we report a systematic characterization of DMPC/DHPC assemblies at 20 °C. To investigate the phase behavior, optical density OD500, size (by dynamic light scattering), membrane fluidity 1/PDPH (using 1,6-diphenyl-1,3,5-hexatriene), and membrane polarity GP340 (using 6-dodecanoyl-N,N-dimethyl-2-naphthylamine) were measured as a function of molar ratio of DHPC (XDHPC). Based on structural properties (OD500 and size), large and small assemblies were categorized into Region (i) (XDHPC < 0.4) and Region (ii) (XDHPC ≥ 0.4), respectively. The DMPC/DHPC assemblies with 0.33 ≤ XDHPC ≤ 0.67 (Region (ii-1)) showed gel-phase-like interfacial membrane properties, whereas DHPC-rich assemblies (XDHPC ≥ 0.77) showed disordered membrane properties (Region (ii-2)). Considering the structural and interfacial membrane properties, the DMPC/DHPC assemblies in Regions (i), (ii-1), and (ii-2) can be determined to be vesicle, bicelle, and micelle, respectively.

Synthesis of Bimetallic AuPt Nanoparticles in Aqueous Solution and Electrocatalytic Activity

2005 ◽  
Vol 900 ◽  
Author(s):  
Peter N. Njoki ◽  
Jin Luo ◽  
Aisley Jacob ◽  
Rizwan Munawar ◽  
Bilal Khan ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Electrocatalytic Activity ◽  
Bimetallic Nanoparticles ◽  
Rotating Disk ◽  
Reduction Reaction ◽  
Rotating Disk Electrode ◽  
Morphological Properties ◽  
Nanoparticle Catalysts ◽  
Bimetallic Nanoparticle

ABSTRACTThe ability to control composition and size in the synthesis of bimetallic nanoparticles is important for the exploitation of the bimetallic catalytic properties. This paper reports recent findings of an investigation of the synthesis of gold-platinum (AuPt) bimetallic nanoparticles in aqueous solution via reduction of AuCl4− and PtCl42− using a combination of reducing and capping agents. In addition to characterization of the morphological properties of the AuPt nanoparticles using TEM and XRD, the electrocatalytic activity of the carbon-supported AuPt nanoparticle catalysts was also examined for oxygen reduction reaction (ORR) using the rotating disk electrode (RDE) technique. The findings have implications to the design of bimetallic nanoparticle catalysts for fuel cell reactions.

Synthesis and characterization of rutile TiO2 nanowhiskers

1999 ◽  
Vol 14 (8) ◽  
pp. 3346-3354 ◽  
Author(s):  
G. L. Li ◽  
G. H. Wang ◽  
J. M. Hong
Keyword(s):  
Aqueous Solution ◽  
Cross Sections ◽  
Packing Density ◽  
Annealing Temperature ◽  
Precursor Powder ◽  
Molar Ratio ◽  
Synthesis And Characterization ◽  
Optimum Temperature ◽  
Rutile Tio2

Rutile TiO2 nanowhiskers have been synthesized by annealing a precursor powder in which NaCl and Ti(OH)4 particles were homogeneously mixed. The precursor powder was prepared by mixing three kinds of inverse microemulsions (μE) containing TiCl4 aqueous solution, ammonia, and NaCl aqueous solution, respectively, followed by washing with acetone. Annealing temperature and packing density of Ti(OH)4 in the precursor powder influenced the formation of rutile nanowhiskers. The optimum temperature was 750 °C. TiO2 nanowhiskers obtained by annealing a precursor powder in which the molar ratio of sodium to titanium was 400 at 750 °C for 2 h had diameters of 10–50 nm and lengths of several micrometers. They were straight rods with square cross sections, and the side surfaces were composed of four equivalent {110} planes.

Systematical Characterization of Phase Behaviors and Membrane Properties of Fatty Acid/Didecyldimethylammonium Bromide Vesicles

Langmuir ◽  
2014 ◽  
Vol 30 (43) ◽  
pp. 12721-12728 ◽  
Author(s):  
Keishi Suga ◽  
Tomoya Yokoi ◽  
Dai Kondo ◽  
Keita Hayashi ◽  
Seiichi Morita ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Membrane Properties ◽  
Phase Behaviors

Preparation and Characterization of Radiation Grafted Proton Exchange Membranes of LLDPE

2010 ◽  
Vol 123-125 ◽  
pp. 1091-1094
Author(s):  
Sabia Sultana ◽  
Mubarak A. Khan ◽  
Nazia Rahman ◽  
Maksudur R. Khan
Keyword(s):  
Irradiation Time ◽  
Low Cost ◽  
Proton Exchange Membranes ◽  
Exchange Capacity ◽  
Proton Exchange ◽  
Membrane Properties ◽  
Molar Ratio ◽  
Grafting Technique ◽  
Exchange Membrane

As the demand for radiation grafted Proton Exchange Membranes (PEMs) is intensifying, interest in new materials for preparing PEM is rapidly increasing. This study aims to develop sustainable low-cost highly conductive PEM. In our work we have prepared linear low density polyethylene (LLDPE) based PEM and investigated the membrane characteristics. Simultaneous radiation grafting technique has been applied to introduce the styrene monomer onto the LLDPE films by UV radiation under atmospheric circumstances. It has been observed that grafting yield gradually changes depending on the irradiation time and monomer molar ratio. We have performed experiments to assess certain membrane properties, such as water uptake, ion exchange capacity with respect to their applicability in fuel cells. Our experimental results demonstrate the effectiveness of LLDPE based PEM as a cation exchange membrane.

scholarly journals Morphological Estimation of DMPC/DHPC Self-Assemblies in Diluted Condition: Based on Physicochemical Membrane Properties

2018 ◽  
Author(s):  
Shogo Taguchi ◽  
Keishi Suga ◽  
Keita Hayashi ◽  
Yukihiro Okamoto ◽  
Hidemi Nakamura ◽  
...  
Keyword(s):  
Phase Transition ◽  
Self Assembly ◽  
The Self ◽  
Membrane Properties ◽  
Fluorescence Probes ◽  
Molar Ratio ◽  
Lipid Concentration ◽  
Total Lipid Concentration ◽  
Gel Phase ◽  
Ordered State

Self-assembly membranes, composed of 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) and 1,2-dihexanoyl-sn-glycero-3-phosphocholine (DHPC), were characterized at the total lipid concentration below 20 mM. The sizes of the assemblies varied depending on the molar ratio of DMPC and DHPC (q = [DMPC]/[DHPC]). The small assemblies with diameter of ca. 10 nm were formed at q &le; 2.0 at 20 &ordm;C (below phase transition temperature of DMPC). The physicochemical membrane properties were then studied using fluorescence probes, 1,6-diphenyl-1,3,5-hexatriene and 6-dodecanoyl-N,N-dimethyl-2-naphthylamine, upon the dilution. DHPC micelle showed a higher membrane fluidity, while the DMPC/DHPC membranes at q &ge; 0.5 showed lower membrane fluidities as well as DMPC vesicle in gel (ordered) phase. Upon dilution, the ordered membrane properties were maintained while the solution turbidities increased, implying the morphological change of the self-assembly, bicelle to the vesicle in gel phase. Based on the obtained results, a phase diagram of DMPC/DHPC binary system (at 20 &ordm;C) is described: (i) the bicelle suspension is transparent and the membrane is in ordered state, (ii) the micelle suspension is transparent and the membrane is in disordered state, (iii) the vesicle suspension is turbid and the membrane is in ordered state.

Characterization of Tamm-Horsfall Urinary Glycoprotein

1973 ◽  
Vol 31 ◽  
pp. 420-421
Author(s):  
John P. Robinson ◽  
J. David Puett
Keyword(s):  
Electron Microscopy ◽  
Circular Dichroism ◽  
Secondary Structure ◽  
Quaternary Structure ◽  
Normal Adult ◽  
Morphological Properties ◽  
Adult Males ◽  
Circular Dichroïsm ◽  
Urinary Glycoprotein

Much work has been reported on the chemical, physical and morphological properties of urinary Tamm-Horsfall glycoprotein (THG). Although it was once reported that cystic fibrotic (CF) individuals had a defective THG, more recent data indicate that THG and CF-THG are similar if not identical.No studies on the conformational aspects have been reported on this glycoprotein using circular dichroism (CD). We examined the secondary structure of THG and derivatives under various conditions and have correlated these results with quaternary structure using electron microscopy.THG was prepared from normal adult males and CF-THG from a 16-year old CF female by the method of Tamm and Horsfall. CF female by the method of Tamm and Horsfall.

Characterization of molecular, physicochemical, and morphological properties of starch isolated from germinated highland barley

2021 ◽  
Vol 42 ◽  
pp. 101052
Author(s):  
Waleed AL-Ansi ◽  
Amer Ali Mahdi ◽  
Qais Ali Al-Maqtari ◽  
Bilal Mushtaq Sajid ◽  
Abduqader Al-Adeeb ◽  
...  
Keyword(s):  
Morphological Properties ◽  
Highland Barley

scholarly journals Synthesis and Characterization of Partially Renewable Oleic Acid-Based Ionomers for Proton Exchange Membranes

Polymers ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 130
Author(s):  
Carlos Corona-García ◽  
Alejandro Onchi ◽  
Arlette A. Santiago ◽  
Araceli Martínez ◽  
Daniella Esperanza Pacheco-Catalán ◽  
...  
Keyword(s):  
Oleic Acid ◽  
Proton Conductivity ◽  
Electrochemical Impedance ◽  
Proton Exchange Membranes ◽  
Proton Exchange ◽  
Molar Ratio ◽  
Aromatic Diamines ◽  
Chemical Structures ◽  
Long Chain

The future availability of synthetic polymers is compromised due to the continuous depletion of fossil reserves; thus, the quest for sustainable and eco-friendly specialty polymers is of the utmost importance to ensure our lifestyle. In this regard, this study reports on the use of oleic acid as a renewable source to develop new ionomers intended for proton exchange membranes. Firstly, the cross-metathesis of oleic acid was conducted to yield a renewable and unsaturated long-chain aliphatic dicarboxylic acid, which was further subjected to polycondensation reactions with two aromatic diamines, 4,4′-(hexafluoroisopropylidene)bis(p-phenyleneoxy)dianiline and 4,4′-diamino-2,2′-stilbenedisulfonic acid, as comonomers for the synthesis of a series of partially renewable aromatic-aliphatic polyamides with an increasing degree of sulfonation (DS). The polymer chemical structures were confirmed by Fourier transform infrared (FTIR) and nuclear magnetic resonance (1H, 13C, and 19F NMR) spectroscopy, which revealed that the DS was effectively tailored by adjusting the feed molar ratio of the diamines. Next, we performed a study involving the ion exchange capacity, the water uptake, and the proton conductivity in membranes prepared from these partially renewable long-chain polyamides, along with a thorough characterization of the thermomechanical and physical properties. The highest value of the proton conductivity determined by electrochemical impedance spectroscopy (EIS) was found to be 1.55 mS cm−1 at 30 °C after activation of the polymer membrane.

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