We figured out periodic undulations of lamellae “zigzags” in liquid crystals under confinement by glass and patterned silicon hybrid cell, but in the absence of applied fields. The optical and internal structures of...
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We figured out periodic undulations of lamellae “zigzags” in liquid crystals under confinement by glass and patterned silicon hybrid cell, but in the absence of applied fields. The optical and internal structures of zigzags have been investigated from mesoscopic scale to molecular level by convoluting real and reciprocal space probes, such as polarized light microscopy, scanning electron microscopy, and microbeam x-ray diffraction. The homeotropic anchoring happens at air/liquid crystal, while planar one appears at glass or patterned silicon surfaces. The wetting and displacement of lamellae near the glass surface give rise to tilting and bending in the stacking of lamellae. This can provide a solution for the origin of periodic zigzags: asymmetric strain exerted to lamellae at two-dimensional glass surface and one-dimensional-like pattern. This can give a hint for potential photonic applications such as optical gratings and modulators due to its high periodicity.
Two kinds of gel-type dye-sensitized solar cells (DSSCs), composed of two types of electrolytes, were constructed and the respective cell performance was evaluated in this study. One electrolyte, TEOS-Triton X-100 gel...
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Two kinds of gel-type dye-sensitized solar cells (DSSCs), composed of two types of electrolytes, were constructed and the respective cell performance was evaluated in this study. One electrolyte, TEOS-Triton X-100 gel, was based on a hybrid organic/inorganic gel electrolyte made by the sol-gel method and the other was based on poly(vinyidene fluoride-co-hexafluoro propylene) (PVDF-HFP) copolymer. TEOS-Triton X-100 gel was based on the reticulate structure of silica, formed by hydrolysis, and condensation of tetraethoxysilane (TEOS), while its organic subphase was a mixture of surfactant (Triton X-100) and ionic liquid electrolytes. Both DSSC gel-type electrolytes were composed of iodine, 1-propy-3-methyl-imidazolium iodide, and 3-methoxypropionitrile to create the redox couple of I3-/I-. Based on the results obtained from the I-V characteristics, it was found that the optimal iodine concentrations for the TEOS-Triton X-100 gel electrolyte and PVDF-HFP gel electrolyte are 0.05 M and 0.1 M, respectively. Although the increase in the iodine concentration could enhance the short-circuit current density (JSC), a further increase in the iodine concentration would reduce the JSC due to increased dark current. Therefore, the concentration of I2 is a significant factor in determining the performance of DSSCs. In order to enhance cell performance, the addition of nanosilicate platelets (NSPs) in the above-mentioned gel electrolytes was investigated. By incorporating NSP-Triton X-100 into the electrolytes, the JSC of the cells increased due to the decrease of diffusion resistance, while the open circuit voltage (VOC) remained almost the same. As the loading of the NSP-Triton X-100 in the TEOS-Triton X-100 gel electrolyte increased to 0.5 wt%, the JSC and the conversion efficiency increased from 8.5 to 12 mA/cm2 and from 3.6% to 4.7%, respectively. However, the JSC decreased as the loading of NSP-Triton X-100 exceeded 0.5 wt%. At higher NSP-Triton X-100 loading, NSPs acted as a
In color filter industry, a problem was found that the adhesion strength between glass substrate and black matrix was largely decreased after ITO sputtering process. In order to solve this problem, a new UV-curable si...
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The dielectric response of oxidized multi-walled carbon nanotube / epoxy resin composites, is investigated with respect to filler content concentration, over a wide temperature and frequency range. Specimens, below th...
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The dielectric response of oxidized multi-walled carbon nanotube / epoxy resin composites, is investigated with respect to filler content concentration, over a wide temperature and frequency range. Specimens, below the percolation threshold, exhibit similar behaviour to that of the neat epoxy. Two relaxation modes are observed in the low temperature region, attributed to the re-arrangement of small parts of the polymer chain (γ-mode) and the reorientation of polar side groups (β-mode) respectively, where in the high temperature region the evolution of the a-mode is present. Direct current (DC) conduction follows the Vogel - Tamann - Fulcher equation as expected. The dielectric response of specimens, above the percolation threshold, follows the "Random Free Energy Barrier Model". DC conductivity exhibits Arrhenius temperature dependence with two distinct regions. The activation energies of both regions were evaluated. The contact resistance between two adjacent carbon nanotubes was also calculated. The effective dielectric constant as well as the capacitance of the specimens, above the percolation threshold, can be modulated by means of an applied DC bias voltage.
Calcium alginate fibers were prepared by wet spinning of sodium alginate into a coagulating bath containing calcium *** thermal degradation and flame retardancy of calcium alginate fibers were investigated with therma...
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Calcium alginate fibers were prepared by wet spinning of sodium alginate into a coagulating bath containing calcium *** thermal degradation and flame retardancy of calcium alginate fibers were investigated with thermal gravimetry(TG),X-ray diffraction(XRD),limiting oxygen index(LOI) and cone calorimeter(CONE).The results show that calcium alginate fibers are inherently flame retardant with a LOI value of 34,and the heat release rate(HRR),total heat release(THR),CO and CO_2 concentrations during com...
A coarse-grained (CG) model of Poly (N -isopropylacryl-amide) (PNIPAM, a kind of thermo-sensitive polymer with widely application) single chain at high temperature is developed from atomistic simulation using Iterativ...
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A convenient pathway to control drug release from hybrid assembly nanoparticles of several kinds of copolymers was investigated in this paper. Three kinds of biodegradable amphiphilic copolymers, poly(ethylene glycol)...
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A convenient pathway to control drug release from hybrid assembly nanoparticles of several kinds of copolymers was investigated in this paper. Three kinds of biodegradable amphiphilic copolymers, poly(ethylene glycol)-block-poly(L-lactic acid), poly(ethylene glycol)-block-poly(D,L-lactic acid) and poly(ethylene glycol)-block-polycaprolactone-poly(ethylene glycol) were used to assemble into hybrid assembly nanoparticles as carriers of paclitaxel. The results show that small spherical hybrid assembly nanoparticles (diameter
Poly(3-(p-methyl)benzyl-3,4-dihydro-6-methyl-2H-1,3-benzoxazine) (poly(pCpT)), which was obtained from electrochemicalpolymerization in acetonitrile/alkali aqueous solution, was characterized by FT-IR, UV-Vis and 1H-...
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Poly(3-(p-methyl)benzyl-3,4-dihydro-6-methyl-2H-1,3-benzoxazine) (poly(pCpT)), which was obtained from electrochemicalpolymerization in acetonitrile/alkali aqueous solution, was characterized by FT-IR, UV-Vis and 1H-NMR. The results indicate a ring-opening structure of the polymer. By using a rotating-ring disc electrode (RRDE), the electrochemical behaviors of polymerization were studied and the polymerization mechanism was proposed.
The tetragonally packed cylinder structure was observed in the of comb-coil PS-P4VP(DBSA) block copolymer bearing heteroarm star architecture, where tetragonal lattice appeared at the intermediate binding fraction of ...
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The tetragonally packed cylinder structure was observed in the of comb-coil PS-P4VP(DBSA) block copolymer bearing heteroarm star architecture, where tetragonal lattice appeared at the intermediate binding fraction of DBSA on P4VP block. The heteroarm star PSn-P4VPn, with the average arm number n of both PS and P4VP blocks being 2.6, was prepared by a three three step sequential copolymerization, and the complexes of the copolymer with DBSA were prepared according to the procedure. The SAXS and TEM results have revealed that the heteroarm PS-P4VP(DBSA) comb-coil copolymer exhibits the same self-assembly behavior as its linear counterpart in terms of the effect of the overall binding fraction of comb block on the packing symmetry of the PS cylinders. The hexagonal packing became stable at the stoichiometric binding that resulted in the orthogonal orientation of the smaller scale lamellae with respect to the PS cylinder, demonstrating the self organization behavior in terms of packing symmetry.
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