Quantitative analysis of angle‐resolved XPS spectra recorded in parallel data acquisition mode

The effects of anisotropy of the photoionization cross‐section and elastic scattering of photoelectrons in solids are investigated for angle‐resolved XPS spectra (ARXPS) recorded from α–Al₂O₃ substrate in parallel data acquisition mode. It is shown that for quantitative analysis of ARXPS spectra recorded in parallel data acquisition mode it is essential to account for the anisotropies of the photoionization cross‐sections of the detected photoelectrons for the concerned elements in the solid due to variation of the angle between the incident x‐rays and the detected photoelectrons. Neglecting the effect of elastic scattering only leads to minor errors in quantitative analysis of the ARXPS spectra. By adopting experimentally determined values for the relative sensitivity factors of the concerned photoelectrons in the solid as a function of the detection angle, cumbersome corrections for the effects of anisotropy of the photoionization cross‐section and elastic scattering can be avoided. Copyright © 2004 John Wiley & Sons, Ltd.     

The dynamic contact angle I. Dependence of the receding contact angle on velocity in the surfactant-containing three-phase system

Spontaneous three-phase contact (tpc) motion is investigated in order to determine the dependence of the static contact angle on tpc velocity in surfactant-containing systems after recession. To interpret the experimental results, the molecular-kinetic sitechanging theory and the hydrodynamic theory were considered. It is shown that, especially at very high tpc velocities, the experimental results are not thoroughly described by these theories. The deviations are explained as a surfactant transfer from the liquid/gas to the solid/gas interface which, under insufficient afterdiffusion, leads to an increase in surface tension and to a changed surface rheology. This mechanism could be governed by a model.     

Surface modification of LDPE film by CO2 pulsed laser irradiation

The influence of the pulsed CO₂ laser irradiation on the surface structure of the LDPE film was investigated. Significant changes were observed on the surface of laser treated films as it was verified by the attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy, scanning electron microscopy and contact angle-measurement. Formation of polar functional groups onto the LDPE surfaces exhibited by the ATR-FTIR spectra was shown to be strongly dependent on the number of the CO₂ laser pulses. The intensity of the polar groups increased with increasing the number of pulses up to two and then slightly decreased at three laser pulses. This was also confirmed with the contact angle measurements in which the sample subjected to two laser pulses showed the highest wettability i.e. the lowest water drop contact angle. The concentration of peroxide groups formed on the surface of the laser treated films was determined quantitatively by UV spectroscopic method using iodide procedure. The latter results showed a similar trend with the results obtained using FTIR spectroscopy.     

New evidences of glass transitions and microstructures of soy protein plasticized with glycerol

Soy protein isolate (SPI) and glycerol were mixed under mild (L series) and severe (H series) mixing conditions, respectively, and then were compression-molded at 140 degrees C and 20 MPa to prepare the sheets (SL and SH series). The glass transition behaviors and microstructures of the soy protein plasticized with glycerol were investigated carefully by using differential scanning calorimetry and small-angle X-ray scattering. The results revealed that there were two glass transitions in the SPI/glycerol systems. When the glycerol contents ranged from 25 to 40 wt.-%, all of the SL- and SH-series sheets showed two glass transition temperatures (T(g1) and T(g2)) corresponding to glycerol-rich and protein-rich domains, respectively. The T(g1) values of the sheets decreased from -28.5 to -65.2 degrees C with an increase of glycerol content from 25 to 50 wt.-%, whereas the T(g2) values were almost invariable at about 44 degrees C. The results from wide-angle X-ray diffraction and small-angle X-ray scattering indicated that both protein-rich and glycerol-rich domains existed as amorphous morphologies, and the radii of gyration (R(g)) of the protein-rich domains were around 60 nm, a result suggesting the existence of stable protein domains. The results above suggest that protein-rich domains were composed of the compact chains of protein with relatively low compatibility to glycerol and glycerol-rich domains consisted of relative loose chains that possessed good compatibility with glycerol. The significant microphase separation occurred in the SPI sheets containing more than 25 wt.-% glycerol, with a rapid decrease of the tensile strength and Young's modulus. [illustration in text].     

Recent advancement and development of chitin and chitosan-based nanocomposite for drug delivery: Critical approach to clinical research

This review depicts the exposure of chitin and chitosan base multifunctional nanomaterial composites for promising applications in field of biomedical science structure, synthesis as well as potential application from a colossal angle. We elaborated critically each of the chitin and chitosan base nanomaterial with its potential application toward biomedical science. For different biomedical applications it use in form of hydrogels, microsphere, nanoparticles, aerogels, microsphere and in form of scaffold. Due to this it had been blended with different polymer such as starch, cellulose, alginate, lipid, hyaluronic acid, polyvinyl alcohol and caboxymethyl cellulose. In this review article, a comprehensive overview of combination of chitin and chitosan base nanomaterial with natural as well as synthetic polymers and their biomedical applications in biomedical field involving drug delivery system all the technical scientific issues have been addressed; highlighting the recent advancements.     

Analysis of orientation fluctuation in fluids by small angle X-ray scattering

The small angle X-ray scattering of molecular fluids contains information on particular aspects of their orientational order. Examples are given for the case of the isotropic, nematic and cholesteric phases of mesogenic molecules. It is shown that the distribution of the molecular centers relative to the direction defined by the molecular long axes can be analysed by means of small angle X-ray scattering. An approximate expression for the circulation correlation function is given.     

NaCl、KCl、Na2CO3、K2CO3等电解质溶液对含水卵磷脂液晶结构影响的SAXS研究

This paper describs the structural character of liquid-crystal of 5%H_2O-egg yolk phospholipid (PC) containing in avarious salt's solution, the layer distance was determined by means of SAXS method. Experimental results show that the layer distance of liquid crystal phase is increased in the 5%H_2O-PC system as the amount of solution of NaCl or KCl is increased. But on the addition of Na_2CO_3 or K_2CO_3 solution into the 5%H_2O-PC system the layer distance of liquid-crystal phase is held constant. It is considered that Na_2CO_3 or K_2CO_3, might be hydrolyzed producing OH~- ions, so that the latter could stablize the interfacial potential between water and egg yolk phospholipid. Absence of this behavior for solution of NaCl or KCl might be due to NaCl and KCl are salts which formed by strong acids and strong bases.     

Synthesis and X-ray structure analysis of benzoic acid [1-(6-methyl-2,4-dioxo-3,4-dihydro-2H-pyran-3-yl)eth-(E)-ylidene]-hydrazide with a water molecule (C15H14N2O4?H2O)

The crystal structure of the title compound has been determined by X-ray diffraction methods. It crystallizes in the monoclinic space group P2₁/n with cell parameters a = 7.097(1) Å, b = 19.257(1) Å, c = 10.893(1) Å, = 106.17(2), V = 1429.8(3) ų and Z = 4. The final reliability index is 0.059 for 2419 observed reflections. The molecule comprises of two six- membered rings which are abridged together through a network of C–N, N–N and C–N bonds. There are three keto functional groups and two methyl groups at various locations of the molecule. The C9 atom of methyl group and O2 of the keto group are deviated significantly from the mean plane of the molecule. Both the six-membered rings are planar and it is evident from the magnitude of their exocyclic torsion angles. The molecular structure is stabilized by few intra and intermolecular hydrogen bonds.     

Crystal structures of 1,1-di(p-substituted phenyl)-2,2-dinitroethylenes

The X-ray crystal structures of 1,1-di(p-methylphenyl)-2,2-dinitroethylene (2), 1,1-di(p-methoxylphenyl)-2,2-dinitroethylene (3), 1,1-di(p-fluorophenyl)-2,2- dinitroethylene (4), 1,1-di(p-chlorophenyl)-2,2-dinitroethylene (5), and 1-phenyl-1- (p-nitrophenyl)-2,2-dinitroethylene (6) are reported and compared with that of 1,1-diphenyl-2,2-dinitroethylene (1). Owing to steric repulsion between the aryl rings, the single bond lengths between C(1) and the two ring carbons atoms are longer than the normal sp²–sp² bond distance of 1.46 Å. For 4–6 in which the aryl rings contain electron-withdrawing substituents (F, Cl, NO₂), the double bonds between C(1) and C(2) are shorter than those in 2 and 3, whose aryl rings containing electron-donating substituents. Furthermore, the steric repulsion between the aryl rings and C NO₂ fragments results in an appreciable twist about the central double bond. The two aryl rings of compounds 1–6 make dihedral angles of 77.7, 66.6, 62.8, 80.9, 82.0, and 71.2°, and the two C NO₂ fragments make dihedral angles of 68.5, 67.8, 65.9, 76.9, 73.0, and 71.9°, respectively.