Studies on the phase behavior and solubilization of the microemulsion formed by surfactant-like ionic liquids with ɛ–β-fish-like phase diagram

The phase behavior and the solubilization of the microemulsion systems surfactant-like ionic liquids 1-hexadecyl-3-methylimidazolium bromide (C₁₆mimBr), 1-tetradecyl-3-methylimidazolium bromide (C₁₄mimBr), or 1-dodecyl-3-methylimidazolium bromide (C₁₂mimBr)/alcohol/alkane/brine have been studied with ɛ–β-fish-like phase diagram method at 40 °C and an oil-to-water mass ratio of 1:1. From the ɛ–β-fish-like phase diagram, the physicochemical parameters, such as the mass fraction of alcohol in the hydrophile–lipophile-balanced interfacial layer (A ^S), and the solubilities of ionic liquid (S ^O) and alcohol (A ^O) in alkane phase, were calculated. The solubilization of the microemulsion system has been discussed based on the ɛ–β-fish-like phase diagram. The smaller the oil molecule, the longer the alcohol chain length, and the larger the NaCl concentration in water, the larger the solubilization of the microemulsion system. In this paper, the solubilization of the microemulsion stabilized by both C₁₂mimBr and sodium dodecyl sulfonate (sodium dodecyl sulfate) was also investigated with the ɛ–β-fish-like phase diagram. The unequimolar composite of anionic and cationic surfactants can avoid the sedimentation aroused by the strong electrostatic attraction, and an obvious synergism effect in solubilization was obtained.     

Formation of micelles of Pluronic block copolymers in PEG 200

The formation of micelles of Pluronic block copolymers in poly(ethylene glycol) (PEG) was studied using fluorescence, solubilization measurements, and frozen fracture electron microscopy (FFEM) methods at 40 degrees C. It was discovered that surfactants L44 (EO(10)PO(23)EO(10)), P85 (EO(26)PO(40)EO(26)), and P105 (EO(37)PO(56)EO(37)) can form micelles in PEG 200 (PEG with a nominal molecular weight of 200), and the critical micellization concentration (CMC) decreases with increasing molecular weight of the surfactants. The size of the micelles formed by these Pluronic block copolymers is in the range of 6-35 nm. The CMC values in PEG 200 are higher than those in aqueous solutions.     

One step preparation of superhydrophobic polymeric surface with polystyrene under ambient atmosphere

Brassica oleracea-like polymer surface is facilely fabricated by one-step casting process using amorphous polystyrene (PS) under ambient atmosphere. The obtained coatings show excellent superhydrophobicity and only possess unitary micro-scale structure, similar to the natural brassica leaf. In addition, a simple topography analysis also roughly verifies superhydrophobic structure of branched and intermingled sticks and bumps. This process provides a fairly easy procedure for preparing superhydrophobic surface from common plastics. Moreover, it demonstrates that the micro/nano-binary structure is not necessary for superhydrophobicity, while unitary micro-scale structure for a polymer surface can exhibit outstanding water repellency as natural lotus.     

A multianalyte chemosensor on a single molecule: promising structure for an integrated logic gate

A novel fluorescent probe that possess both BODIPY and Rhodamine moieties has been designed for the selective detection of Hg(2+) and Ba(2+) ions on the controlling by a logic gate. The characteristic fluorescence of the Ba(2+)-selective OFF-ON and the Hg(2+)-selective fluorescence bathochromic shift can be observed, and the concept has been used to construct a combinational logic circuit at the molecular level. These results will be useful for further molecular design to mimic the function of the complex logic gates on controlling.     

Designing and tuning properties of a three-dimensional porous quaternary chalcogenide built on a bimetallic tetrahedral cluster [M4Sn3S13] (M=Zn/Sn)

A multifunctional three-dimensional quaternary chalcogenide [Na₅Zn_3.5Sn_3.5S₁₃]·6H₂O has been synthesized by solvothermal reactions. [Na₅Zn_3.5Sn_3.5S₁₃]·6H₂O represents an interesting example of metal chalcogenides that combines semiconductivity, porosity, and light emission in a single structure. It crystallizes in the cubic space group Fm-3c, a=17.8630(3) Å, V=5699.85(17) Å³, Z=8. The compound decomposes at ∼450 °C. A band gap of 2.9 eV is estimated from the optical diffuse reflectance data. A strong photoluminescence peak is observed at 2.43 eV in Mn doped samples. The electronic and optical properties of this compound can be systematically tuned by substitution of metal and chalcogen elements.     

Modification of amorphous poly(ethylene terephthalate) surface by UV light and plasma for fabrication of an electrophoresis chip with an integrated gold microelectrode

Amorphous poly(ethylene terephthalate) (PET), which possess a low softening temperature (T(s)=75 degrees C), was exploited to fabricate the electrophoresis chip with an integrated gold electrode for amperometric detection, with emphases being focused on the PET surface modification via UV light and air plasma. Both UV irradiation and plasma treatment were found to be able to improve the surface wettability, enhance the supported electroosmotic flow (EOF), and increase thermal bonding strength of PET sheets, with the latter being more efficient and less time-consuming than the former in the surface modification. Upon treated with plasma for 2 min, the PET sheets could be thermally bonded at 65 degrees C. T-peer test showed that the bonding strength increased from 10 g/cm for native PET sheets to 1250 g/cm for the plasma treated sheets when chips were bonded at the softening point, Attenuated-total-internal-reflection spectrum showed that, after being exposed to the UV light, carboxylic groups site-selectively formed in the UV-exposed region on PET surface. These UV-induced carboxylic groups were further utilized as the scaffold for preparation of micro-gold electrode via electroless gold plating. By using this established UV-directed electroless plating and the plasma-assisted thermal bonding techniques, the full PET electrophoresis chip with an integrated micro-gold electrode could be fabricated in common chemistry laboratory without the need of clean rooms. The fabricated PET chips were demonstrated for separation and detection of model analytes of dopamine (DA) and catechol (CA). Satisfactory resolution of the two analytes was achieved within 40s, and detection limits of 0.87 microM and 1.28 microM for DA and CA were obtained, respectively.     

Preparation and mechanical properties of poly(chitosan‐g‐DL‐lactic acid) fibrous mesh scaffolds

DL ‐lactic acid was grafted onto chitosan to produce poly(chitosan‐g‐DL ‐lactic acid)(PCLA) without using a catalyst. These PCLAs were then spun into filaments and further fabricated into fibrous mesh scaffolds using an improved wet‐spinning technique. The diameter of filaments in different scaffolds could vary from a few micrometers to several tens of micrometers. The scaffolds exhibited various pore sizes ranging from about 20 µm to more than 200 µm and different porosities up to 80%. The several main processing conditions were optimized for obtaining the desired scaffolds with well‐controlled structures. The tensile and compressive mechanical properties of the mesh scaffolds in both dry and hydrated states were mainly examined. Significantly improved tensile strength and modulus, enhanced compressive modulus, and stress as well as the dimensional stability for these mesh scaffolds in their hydrated state were observed. Copyright © 2007 John Wiley & Sons, Ltd.     

High-resolution microwave spectroscopic and ab initio studies of propanoic acid and its hydrates

High-resolution microwave spectra of the propanoic acid monomer (PPA) and two of its hydrates, the PPA-(H2O) and the PPA-(H2O)2, were recorded using a pulsed nozzle Fourier transform microwave spectrometer. The rotational and centrifugal distortion constants of these species were determined. Agreements between the experimental and ab initio results of these constants, and of the planar moment of inertia, the dipole moments, and the orientation of the PPA relative to the H2O confirm the geometry of the hydrates, i.e. H2O binds to the carboxylic group of PPA and forms hydrogen-bonded ring complexes. The equilibrium constant and the change of entropy and enthalpy for the formation of PPA-(H2O) were also derived, based on the calculation of partition functions, to evaluate the abundance of this monohydrate in the troposphere.     

Structural study of the self-assembled fullerene carboxylates: monoadducts versus bisadducts

Laser light scattering and transmission electronic microscopy have been used to study the self-assembled structures of mono- and bisadducts of fullerene carboxylic acids in tetrahydrofuran (THF) and their sodium salts in aqueous solutions, respectively. In THF, the self-association of monoadducts of fullerene carboxylic acid (MFCA) produces large but narrowly distributed particles with R(h) approximately 145 nm. The self-aggregates from the bisadducts of fullerene carboxylic acid (BFCA) in THF are relatively small in size (R(h) approximately 80 nm) due to the better solubility. After the ionization of carboxylic acid groups on the C(60) cage in dilute NaOH solutions, these aggregates dissolved and reorganized. The self-assembly of the monoadducts of sodium carboxylate fullerenes (MSCF) produces small solid spherical particles with R(h) approximately 32 nm. The ratio of R(g)/R(h) approximately 0.83 indicates that the particles have a nearly uniform density. The increase in concentrations leads to strong interparticle associations to form rodlike and irregularly shaped large aggregates. In contrast, the self-assembly of bisadducts of sodium carboxylate fullerenes (BSCF) results in hollow shells with mainly two different size scales of R(h) approximately 23 nm and R(h) approximately 104 nm. At high concentrations, the hollow shells associate and melt together to generate three-dimensional networks.     

Direct chemiluminescent imaging detection of Cu/Zn-superoxidase dismutase, glutathione peroxidase, carbonic anhydrase-III, and catalase in rat liver cytosol separated by native porous gradient polyacrylamide gel electrophoresis

The cytosolic enzymes extracted from rat hepatocytes were separated by native porous gradient-PAGE (PG-PAGE) and were detected with a sensitive and fast chemiluminescence (CL) imaging method. Several peroxidases including glutathione peroxidase, Cu/Zn-superoxidase dismutase, and some other metallo-enzymes such as catalase, carbonic anhydrase-III (CA-III) present in the cytosol of rat hepatocytes have been selectively and sensitively detected by the direct CL imaging method using the luminol-H(2)O(2) chemiluminescent reagents. All detections after PG-PAGE were completed within 9 min. The linear range for the typical metallo-enzyme, e.g., CA-III is 0.75-4.9 microg/mL, with a detection limit of 0.25 microg/mL. In comparison with the traditional CBB-R250 staining method, the detection period decreased about 70 times and the detection sensitivity improved over ten times. Furthermore, two enzymes present in rat liver cytosol were identified employing MALDI-MS analysis of the tryptic digest after PG-PAGE.