Mass‐Spectrometric Observation of Counter Anion Production in SU‐8 Exposed to UV Light and its Use for Dill C Parameter Determination

Photopolymerization is a phenomenon that is the basis of much of today's microfabrication technology and intense research is conducted to improve its control and the characteristics of end products for a variety of applications. The design of microscopic structures often relies on the accurate knowledge and modeling of photopolymer's behavior upon exposure, i.e. the Dill parameters, for each radiation species of interest and therefore the development of flexible characterization techniques is of great importance. SU‐8 is a popular compound that is representative of a whole class that relies on cationic polymerization, where an acid is obtained via photolysis of an onium salt during exposure. Here we report on the observation of SbF₆^? via laser desorption mass spectrometry on SU‐8 exposed to UV light at the wavelength of 365 nm and demonstrate that the yield of this counter‐anion as a function of exposure is consistent with the Dill C parameter value available in the literature. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2019 , 57, 967–972     

Synthesis,characterization, and biological investigation of new mixed-ligand complexes

A novel series of mixed-ligand complexes of 5,5′-{(1E,1E′)-1,4-phenelynebis(diazene-2,1-diyl)}bis(quinolin-8-ol) (H₂L₁) as a primary ligand and 4-aminoantipyrine(L₂) as a secondary ligand with Mn(II) ion were prepared using two general formulae: [Mn₂(H₂L₁)₂(L₂)₂X₄].4Cl (X = OH₂( 1 ), ONO₂⁻( 2 ), Cl=nil; OAc( 3 ), Cl = nil) and [Mn₂(H₂L₁)(L₂)₂(O₂SO₂)₂]( 4 ). Free ligands and their complexes were characterized. Electronic absorption spectra of the mixed-ligand complexes indicate a distorted octahedral geometry around the central metal ion, and the anions X⁻ are in the axial positions for all compounds. The ligands behave in a neutral bidentate manner, through nitrogen atoms and oxygen atoms of the carbonyl group (L₂), whereas H₂L₁ coordinated through nitrogen and OH groups as a neutral bidentate ligand. All complexes do not contain coordinated water molecules, but complex ( 1 ) contains four water molecules. The water molecules are removed in a single step. The complexes exhibited magnetic susceptibility corresponding to five unpaired electrons. The antimicrobial activity of the Mn(II) mixed-ligand complexes ( 1–4 ) against two gram-positive bacteria, three local gram-negative bacteria, and three fungi species was tested. Mn(II) mixed-ligand complex ( 2 ) exhibited significant antibacterial activity against Bacillus cereus, Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae, and Pseudomonas sp. Mixed-ligand complex ( 2 ) exhibited a high potential cytotoxicity against the growth of human lung cancer cells.     

Structural and luminescence characteristics of CuAlxIn1−xSe2 (0 < x ≤ 0.30) chalcopyrite solid solutions

1. Download : Download high-res image (112KB)
2. Download : Download full-size image

     

Three-dimensional interfacial fracture analysis of a one-dimensional hexagonal quasicrystal coating

In this paper, the three-dimensional (3D) interfacial fracture is analyzed in a one-dimensional (1D) hexagonal quasicrystal (QC) coating structure under mechanical loading. A planar interface crack with arbitrary shape is studied by a displacement discontinuity method. Fundamental solutions of interfacial concentrated displacement discontinuities are obtained by the Hankel transform technique, and the corresponding boundary integral-differential equations are constructed with the superposition principle. Green’s functions of constant interfacial displacement discontinuities within a rectangular element are derived, and a boundary element method is proposed for numerical simulation. The singularity of stresses near the crack front is investigated, and the stress intensity factors (SIFs) as well as energy release rates (ERRs) are determined. Finally, relevant influencing factors on the fracture behavior are discussed.     

Kinematics of layered reinforced-concrete planar beam finite elements with embedded transversal cracking

In this work crack formation and development is addressed and implemented in a planar layered reinforced-concrete beam element. The crack initiation and growth is described using the strength criterion in conjunction with exact kinematics of the interlayer connection. In this way a novel embedded-discontinuity beam finite element is derived in which the tensile stresses in concrete at the crack position reaching the tensile strength will trigger a crack to open. Since the element is multi-layered, in this way the crack is allowed to propagate through the depth of the beam. The cracked layer(s) will involve discontinuity in the cross-sectional rotation equal to the crack-profile angle, as well as a discontinuity in the position vector of the layer’s reference line. A bond–slip relationship is superimposed onto this model in a kinematically consistent manner with reinforcement being treated as an additional layer of zero thickness with its own material parameters and a constitutive law implemented in the multi-layered beam element.     

Effect of synthesis parameters on the structural,morphological characteristics,and photocatalytic activity of La2O3 nanoparticles

This study investigates the influence of synthesis processes such as sonication, sol-gel, and microwave on the production of highly crystalline Lanthanum oxide nanoparticles (La₂O₃) employing Lanthanum nitrate and Ammonium hydroxide (NH₄OH) as precursors. X-ray diffraction (XRD), particle size analysis (DLS), Field emission scanning electron microscopy (FESEM), Fourier-transform infrared spectroscopy (FTIR), ultraviolet–visible absorption spectroscopy (UV–Vis), and electrochemical impedance spectroscopy (EIS) were used to examine the most effective processing method and its effects on the nanoparticle characteristics, such as structure, morphology, and optical and electrical behavior. Sonication produces La₂O₃ NPs with a smaller crystalline size, an agglomerated nanorod structure, a higher bandgap, and better electrical responsiveness than sol-gel and microwave techniques. Structural and optical characterization tests discovered this. The photocatalytic degradation activity of cationic Safranin and anionic Congo red dye exhibits degradation efficiency of around 90.13% and 89.66%, respectively.     

Experimental analysis and thermodynamic modelling of Nitroxynil solubility in pure solvent and binary solvent

Nitroxynil(NIT) is a commonly used anti-liver fluke drug for cattle and sheep, Its solubility is closely related to its preparation. In this work, the molar solubility of NIT in nine pure solvents (methanol, ethanol, 1,2-propanediolethyl, isopropanol, ethyl acetate, acetonitrile, n-butanol, phemethylol) and two kinds of binary mixtures with different ratio(ethanol + phemethylol; ethanol + acetonitrile) was determined by shake flask method over the temperature from 278.15 ～ 323.15 K at atmosphere pressure. Results show that the solubility of NIT in all tested solvents was increased with raised temperature. In mono-solvents, the mole fraction solubility of NIT was highest in phemethylol and the solubility order is: phemethylol > acetonitrile > ethyl acetate > methanol > n-butanol > ethanol > 1,2-propanediolethyl > isopropanol > water. In binary solvents, the mole fraction solubility increased with increasing ratio of phemethylol/acetonitrile. In mono-solvents, the modified Apelblat equation, λh equation, Van't Hoff model were applied to correlate the solubility data. In binary solvents, the modified Apelblat equation, λh equation, GSM model and Jouyban-Acree model were to correlate the solubility data. Solubility order of NIT in nine pure solvent and two binary solvent systems were analysed by using the Hansen solubility parameter (HSP). Activity coefficient was to access the solute–solvent molecular interactions. In addition, the dissolution of NIT is an endothermic and entropy-friendly process, since thermodynamic parameters such as enthalpy, entropy, and apparent standard Gibbs free energy are all greater than zero. The results will supply some essential data on recrystallization process, purification and formulation development of NIT in pharmaceutical applications.     

Controlled Formation of Polymer Nanocapsules with High Diffusion‐Barrier Properties and Prediction of Encapsulation Efficiency

Polymer nanocapsules with high diffusion‐barrier performance were designed following simple thermodynamic considerations. Hindered diffusion of the enclosed material leads to high encapsulation efficiencies (EEs), which was demonstrated based on the encapsulation of highly volatile compounds of different chemical natures. Low interactions between core and shell materials are key factors to achieve phase separation and a high diffusion barrier of the resulting polymeric shell. These interactions can be characterized and quantified using the Hansen solubility parameters. A systematic study of our copolymer system revealed a linear relationship between the Hansen parameter for hydrogen bonding (δ_h) and encapsulation efficiencies which enables the prediction of encapsulated amounts for any material. Furthermore EEs of poorly encapsulated materials can be increased by mixing them with a mediator compound to give lower overall δ_h values.     

Prediction models for the key mechanical properties of EPDM/PP blends as affected by processing parameters and their correlation with stress relaxation and phase morphologies

The optimum condition of processing parameters (mixing temperature, rotor speed, fill factor, and blend ratio) and prediction models for the best key mechanical properties of ethylene propylene diene terpolymer/polypropylene thermoplastic vulcanizates (EPDM/PP TPVs) was investigated by using the Taguchi's optimization technique and data analysis. The results reveal that all of the processing parameters affected significantly the mechanical properties of the EPDM/PP TPVs, but specifically the blend ratio contributed more than 90% in effect size on tensile strength and tension set. There were three main factors, the mixing temperature, the fill factor, and the blend ratio, influencing the elongation at break. Furthermore, the mathematic models were effective and reliable in predicting the properties of TPVs. The correlation of mechanical properties, stress relaxation, and phase morphologies of the TPVs prepared from the predicted models was also investigated. It can be summarized that the morphological structure and stress relaxation of the TPVs were strongly governed by the EPDM content in the blend ratio. That is, the higher the EPDM content, the better phase morphology having smaller size of the vulcanized EPDM particles distributed in the PP matrix and the higher rate of stress relaxation. Moreover, these two properties were then principally pushing the mechanical characteristics of the EPDM/PP TPVs. Copyright © 2015 John Wiley & Sons, Ltd.