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1.
Random copolymers of poly{(methacrylamide)-co-(vinyl trimethoxysilane)} and poly{(methacrylic acid)-co-(vinyl trimethoxysilane)} were synthesized via a free radical polymerization reaction. Acid catalyzed sol-gel process of tetraethylorthosilicate (TEOS) with aforementioned polymers in the presence of methyl xanthine class of alkaloid like caffeine resulted in the formation of highly transparent monoliths. Solvent extraction of the template leaves behind the recognition sites intact with high selectivity towards the print molecule. The ionic and non-specific adsorptions, which are considered to be the main disadvantages of the molecularly imprinted polymers (MIP), are prevented to a considerable extent by the end capping of surface silanol groups. The template binding efficiencies of MIP were determined by HPLC analysis. 相似文献
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L. Barral F.J. Díez S. García-Garabal J. López B. Montero R. Montes C. Ramírez M. Rico 《European Polymer Journal》2005,41(7):1662-1666
Lifetime of the epoxy system formed by diglycidyl ether of bisphenol A, DGEBA/4,4′-diaminediphenylmethane, DDM, modified with the silsesquioxane, glycidylisobutyl-POSS, was calculated from thermogravimetric analysis. The activation energy of the decomposition of this system was evaluated by the integral method developed by Flynn-Wall-Ozawa (E = 88.9 ± 2.1 kJ mol−1) and by Coats and Redfern method (E = 85.2 ± 1.5 kJ mol−1). The kinetic parameters have been used to estimate the lifetime of the system POSS/DGEBA/DDM. The obtained results by two different ways are similar. 相似文献
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A fully-coupled model for a piezoelectric hetero-junction subjected to a pair of stresses is proposed by discarding the depletion layer approximation. The effect of mechanical loadings on PN junction performance is discussed in detail. Numerical examples are carried out for a p-Si/ZnO-n hetero-junction under a pair of stresses acting on the ntype ZnO portion near the PN interface, where ZnO has the piezoelectric property while Si is not. It is found that the bottom of conduction band is lowered/raised near the two loading points due to the decrease/increase in the electron potential energy there induced by a tensile-stress mode via sucking in majority-carriers from two outside regions, which implies appearance of a potential barrier and a potential well near two loading points. Furthermore, the barrier height and well depth gradually become large with increasing tensile stress such that more and more electrons/holes are inhaled in loading region from the n-/p-zone, respectively. Conversely, rising/dropping of conduction band bottom is brought out near the two loading points by a compressive-stress mode due to the increase/decrease in the potential energy of electrons by pumping out the majority-carriers from the loading region to the two outside regions. Therefore, a potential well and a potential barrier are induced near the two loading points, such that more and more electrons/holes are driven away from the loading region to the n-zone/p-zone, respectively, with the increasing compressive stress. These effects are important to tune the carrier recombination rate near the PN interface. Thus, the present study possesses great referential significance to piezotronic devices. 相似文献
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新型无机-有机杂化微孔晶体Cd3(BDC)0.5(BTC)2(DMF)(H2O)·3DMF·H3O·H2O的合成与结构 总被引:2,自引:0,他引:2
传统分子筛是以硅氧四面体和铝氧四面体为骨架的微孔晶体材料. 近年来, 以无机-有机结构单元为骨架组成的微孔晶体材料已引起人们的广泛关注[1~19]. 该类材料是由金属离子(或金属氧簇)与有机配体(大多数是芳香多酸和多碱)构成的建筑单元通过共价键或者分子间作用力构成的. 无机-有机杂化晶体材料有多种结构类型, 如1-D, 2-D, 3-D和笼状结构等. 相似文献
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Andreas Sonnauer 《Journal of solid state chemistry》2008,181(3):473-479
Following the strategy of using polyfunctional phosphonic acids for the synthesis of new metal phosphonates, the organic linker molecule 2-phosphonoethanesulfonic acid, H2O3P-C2H4-SO3H (1) (H3L), was synthesized and characterized in detail. The acid was used in a high-throughput (HT) investigation of the system BaCl2/H3L/NaOH/H2O. The HT experiments comprising 48 individual hydrothermal reactions were performed to systematically investigate the influence of pH of the starting mixture as well as the molar ratio Ba2+: H3L. Only two reaction products were observed: small amounts of BaCO3 under basic conditions and BaH(O3P-C2H4-SO3) (2). For compounds 1 and 2 the crystal structures were determined from single-crystal X-ray diffraction data (H2O3P-C2H4-SO3H: trigonal, P32, a=814.58(1), c=861.20(2) pm, Z=3, R1=0.0254, wR2=0.0758 for I>2σ(I); BaH(O3P-C2H4-SO3): orthorhombic, Ibam, a=953.39(19), b=855.55(17), c=867.82(17) pm, Z=4, R1=0.0162, wR2=0.0417 for I>2σ(I)). The structure of H3L (1) is stabilized exclusively by strong hydrogen bonds. Compound 2 is built up by chains of edge sharing BaO8 polyhedra. These chains are connected to a three-dimensional network by the -CH2CH2- linker of the ligand. Thermogravimetric investigation of compound 2, as well as IR spectra of 1 and 2 are presented. 相似文献
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本文报道由H2PDC合成的新型维层状无机-有机骨架晶体Ni(PDC)(H2O)2(H2PDC=吡啶-2,5-二羧酸), 该化合物的一层是由右手螺旋Ni—O—C链与左手螺旋Ni-pdc链组成, 而邻近的一层则是由左手螺旋Ni—O—C链与右手螺旋Ni-pdc链组成, 层与层之间通过氢键作用形成了三维超分子结构. 用ICP、TG、IR和X射线单晶衍射分析等手段对其结构进行表征. 相似文献
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Andreas Sonnauer 《Journal of solid state chemistry》2008,181(11):3065-3070
Following the strategy of using bifunctional phosphonic acids for the synthesis of new metal phosphonates, the flexible ligand 2-phosphonoethanesulfonic acid, H2O3P-C2H4-SO3H (H3L), was used in a high-throughput (HT) and microwave investigation of rare earth phosphonatoethanesulfonates. The HT-investigation led to six isotypic compounds Ln(O3P-C2H4-SO3) with Ln=Ho (1), Er (2), Tm (3), Yb (4), Lu (5) and Y (6). The syntheses were scaled-up in glass reactor tubes in order to obtain larger amounts for a detailed characterization. Based on these results all compounds could be also synthesized by microwave-assisted heating and the influence of reaction time and stirring rate during the synthesis was established. For compound 2 the crystal structure was determined by single-crystal X-ray diffraction. The compounds contain isolated slightly distorted LnO6 octahedra that are connected by the phosphonate and sulfonate groups into a three-dimensional framework. Thermogravimetric investigations demonstrate the high thermal stability of the compounds up to 460 °C. 相似文献
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Mohsen Nikpour Hossein Eshtiagh-Hosseini Masoud Mirzaei Amir Aghaei Kaju Soroush Zarinabadi 《中国化学快报》2010,21(4):501-505
<正>A unique ionic hybrid material[C_6H_(12)N_5O]_3[(PO_4)W__(12)O_(36)]·5H_2O has been synthesized from the reaction of((1H-tetrazole-5- yl)methyl)morpholine andα-H_3[(PO_4)W_(12)O_(36)]·21H_2O.It has successfully been characterized by elemental analysis,IR and ~1H NMR spectroscopies,TGA and single-crystal X-ray diffraction method.The title compound is constructed from the three [C_6H_(12)N_5O]~+ cations andα-Keggin[(PO_4)W_(12)O_(36)]~(3-) polyoxoanion.The most remarkable structural feature of this hybrid can be described as two-dimensional inorganic infinite plane-like(2D/∞)[(PO_4)W_(12)O_(36)]~(3-)) which forming via van der Waals interactions along the x axis. 相似文献