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991.
Hyun‐Ji Kim Yun Jae Lee Seung Sang Hwang Dong Hoon Choi Hoichang Yang Kyung‐Youl Baek 《Journal of polymer science. Part A, Polymer chemistry》2011,49(19):4221-4226
Regioregular poly(3‐hexyl thiophene) (rr‐P3HT)‐based star polymers were synthesized by a crosslinking reaction of the linear rr‐P3HT macroinitiator and ethylene glycol dimethacrylate (EGDMA) crosslinker through Ru‐based atom transfer radical polymerization (ATRP), where the rr‐P3HT macroinitiator was prepared by Grignard metathesis method (GRIM) followed by end functionalization of the ATRP initiator with chlorophenylacetate (CPA) to the rr‐P3HT. Relatively high molecular weight of the star polymers were obtained (Mp = 8,988,000 g/mol), which consisted of large numbers of the rr‐P3HT arm chains radiating from the EGDMA‐based microgel core. The yield of the star polymers were strongly affected by the added amount of the EGDMA crosslinker. The crystalline structure of the rr‐P3HT by intermolecular π‐π stacking interaction gradually decreased as the star polymer formed, which was confirmed by differential scanning calorimeter (DSC), atomic force microscopy (AFM), and electro‐optical analyses. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011 相似文献
992.
Kumaranand Palaniappan Nadia Hundt Prakash Sista Hien Nguyen Jing Hao Mahesh P. Bhatt Yun‐Yue Han Elizabeth A. Schmiedel Elena E. Sheina Michael C. Biewer Mihaela C. Stefan 《Journal of polymer science. Part A, Polymer chemistry》2011,49(8):1802-1808
Poly(3‐hexylthiophene)‐b‐poly(4‐vinylpyridine) diblock copolymer was synthesized by RAFT polymerization of 4‐vinyl pyridine using a trithiocarbonate‐terminated poly(3‐hexylthiophene) macro‐RAFT agent. The optoelectronic properties and the morphology of the block copolymer blends with CdSe quantum dots were investigated. UV‐vis and fluorescence experiments were performed to prove the charge transfer between CdSe and poly(3‐hexylthiophene)‐b‐poly(4‐vinylpyridine) diblock copolymer. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011 相似文献
993.
Kang‐Jun Baeg Dongyoon Khim Dong‐Yu Kim Soon‐Won Jung Jae Bon Koo In‐Kyu You Henry Yan Antonio Facchetti Yong‐Young Noh 《Journal of Polymer Science.Polymer Physics》2011,49(1):62-67
Inkjet‐printed high speed polymeric complementary circuits are fabricated using an n‐type ([poly{[N,N′‐bis(2‐octyldodecyl)‐naphthalene‐1,4,5,8‐bis(dicarboximide)‐2,6‐diyl]‐alt‐5,5′‐(2,2′‐dithiophene)} [P(NDI2OD‐T2), Polyera ActivInk N2200] and two p‐type polymers [poly(3‐hexylthiophene) (P3HT) and a dithiophene‐based polymer (Polyera ActivInk P2100)]. The top‐gate/bottom‐contact (TG/BC) organic field‐effect transistors (OFETs) exhibit well‐balanced and very‐high hole and electron mobilities (μFET) of 0.2–0.5 cm2/Vs, which were enabled by optimization of the inkjet‐printed active features, small contact resistance both of electron and hole injections, and effective control over gate dielectrics and its orthogonal solvent effect (selection of poly(methyl methacrylate) and 2‐ethoxyethanol). Our first demonstrated inkjet‐printed polymeric complementary devices have been integrated to high‐performance complementary inverters (gain >30) and ring oscillators (oscillation frequency ~50 kHz). We believe that the operating frequency of printable organic circuits can be further improved more than 10 MHz by fine‐tuning of the device architecture and optimization of the p‐ and n‐channel semiconductor processing. © 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2010 相似文献
994.
The electrochemical properties of a perfluorosulfonic acid (PFSA) membrane are estimated using a combination of molecular dynamics simulation and statistical thermodynamic model. We obtain all parameters in an ionic conductivity model from an atomistic simulation and remove all adjusted model parameters. From a microscopic point of view, the hydrated PFSA membrane shows micro‐phase segregation which separated into hydrophilic and hydrophobic phases. Our present work originates with this phenomenon and we treat this phase segregation as if it is a continuous phase for each of which the proton (H+) is transported inside the PFSA membrane/solvent (water and alcohols) mixture. The chemical potential for a given system is estimated using a molecular simulation technique to predict the van der Waals interaction energy between the polymer and solvent. In addition, the self diffusion coefficients are calculated from the molecular dynamics simulation. We study various polymer/solvent compositions to understand the concentration dependence of self diffusion coefficient. Our self diffusion coefficients and also the predicted final ionic conductivity agree well with previously reported experimental data. © 2011 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 49: 1455–1463, 2011 相似文献
995.
996.
根据假设建立了复合引发体系SbCl3/AlCl3/D(给电子体)的α-蒎烯聚合动力学模型。研究结果表明,该模型符合该聚合反应实际,可操作性强。用计算机拟合通过该模型首次获得了研究条件下α-蒎烯聚合的链增长速率kp和链终止速率kt值以及聚合活化能。 相似文献
997.
Nicholas Kob Russell S. Drago Vaneica Young John Osegovic 《Reaction Kinetics and Catalysis Letters》1999,66(2):205-210
The regeneration of solid acid catalysts used in alkylation was studied using cal-ad. It was found that an acid site strength
of −ΔH=32 kcal/mol is needed to catalyze the reaction. 相似文献
998.
999.
1000.
Sung Joong Lee Semin Park Jin Young Choi Jae‐Han Shim Eun‐Ho Shin Jeong‐Heui Choi Soo Taek Kim A. M. Abd El‐Aty Jong Sung Jin Dong Won Bae Sung Chul Shin 《Biomedical chromatography : BMC》2009,23(7):719-731
It would be preferable for pesticide residues substituted by hydrolyzable functionality to be analyzed after cooking because their structures are apt to degrade during boiling and/or heating. A liquid chromatography–tandem mass spectrometry (LC‐MS/MS) method for the quantitative determination of 44 pesticide residues with hydrolyzable functional group in five typical vegetable widely consumed in Republic of Korea is described. The sample clean‐up was carried out according to the method of Food Code No. 83 established by the Korea Food and Drug Administration (KFDA). Zorbox XDB‐C18 column was selected for the analysis because of the best peak separation. The LC mobile phase consisted of water and 5 mm methanolic ammonium formate, which resulted in a peak shape with good symmetry at each run. Tandem mass spectroscopic (MS/MS) experiments were performed in ESI positive mode and the multiple reaction monitoring modes. A conventional matrix effect was modified to more comprehensive form 100γij (%). A high matrix effect (30%) was detected for the seven polar pesticides, namely thiamethoxam, clothianidin, acetamiprid, aldicarb, thiacloprid, pirimicarb and methabenzthiazuron. The limits of detection were in the range of 0.1–8.1 µg/kg, indicating a good sensitivity. Most of the recoveries ranged from 70 to 131% with RSDs ≤ 20%. The current method allowed rapid quantitation and identification of low pesticide levels in the cooked vegetable samples. Of the screened pesticide residues, only fluquinconazole and dimethomorph below the maximum residue levels established by the KFDA were detected in onion and cucumber samples. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献