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Ashootosh V. Ambade Dr. Caroline Burd Dr. Mary Nell Higley Kamlesh P. Nair Dr. Marcus Weck Prof. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2009,15(44):11904-11911
We report the synthesis of telechelic poly(norbornene) and poly(cyclooctene) homopolymers by ring‐opening metathesis polymerization (ROMP) and their subsequent functionalization and block copolymer formation based on noncovalent interactions. Whereas all the poly(norbornene)s contain either a metal complex or a hydrogen‐bonding moiety along the polymer side‐chains, together with a single hydrogen‐bonding‐based molecular recognition moiety at one terminal end of the polymer chain. These homopolymers allow for the formation of side‐chain‐functionalized AB and ABA block copolymers through self‐assembly. The orthogonal natures of all side‐ and main‐chain self‐assembly events were demonstrated by 1H NMR spectroscopy and isothermal titration calorimetry. The resulting fully functionalized block copolymers are the first copolymers combining both side‐ and main‐chain self‐assembly, thereby providing a high degree of control over copolymer functionalization and architecture and bringing synthetic materials one step closer to the dynamic self‐assembly structures found in nature. 相似文献
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A host-guest optical sensor for the determination of aliphatic amines as exemplified by octylamine is proposed. It is based on the reversible fluorescence enhancement of heptakis(2,6-di-O-isobutyl)-β-cyclodextrin(DOB-β-CD) hosting tetraphenylporphyrin (TPP) immobilized in poly(vinyl chloride) (PVC) membrane by aliphatic amine extracted from aqueous phase into membrane phase. The optimum membrane contained 1.15 wt % TPP, 6.15 wt % DOB-β-CD as sensing reagent and other membrane materials. The fluorescence enhancement of the membrane resulted from the formation of a stable three-component complex among DOB-β-CD, TPP, and aliphatic amines. With the optimum conditions described, the fluorescence response of the sensor to octylamine shows a good correlation with the theoretically derived equation in the range 1.0 × 10–6 to 8.0 × 10–4 mol/L. The response characteristics including reversibility, response time, reproducibility and lifetime and selectivity of this optical device are also discussed in detail. This sensor has also been applied for the determination of octylamine in water samples containing interferents with satisfactory recovery. 相似文献
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Amita Gupta Alexei Yu Ganin Parmanand Sharma Vikrant Agnihotri LM Belova KV Rao Mikhail E Kozlov AA Zakhidov RH Baughman 《Pramana》2002,58(5-6):1051-1059
We present studies of novel nanocomposites of BiNi impregnated into the structure of opals as well as inverse opals. Atomic force microscopy and high resolution elemental analyses show
a highly ordered structure and uniform distribution of the BiNi filler in the matrix. These BiNi-based nanocomposites are
found to exhibit distinct ferromagnetic-like ordering with transition temperature of about 675 K. As far as we know there
exists no report in literature on any BiNi compound which is magnetic. 相似文献
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Higley MN Pollino JM Hollembeak E Weck M 《Chemistry (Weinheim an der Bergstrasse, Germany)》2005,11(10):2946-2953
A novel methodology for the formation of block copolymers has been developed that combines ring-opening metathesis polymerization (ROMP) with functional chain-transfer agents (CTAs) and self-assembly. Telechelic homopolymers of cyclooctene derivatives end-functionalized with hydrogen-bonding or metal-coordination sites are formed through the combination of ROMP with a corresponding functional CTA. These telechelic homopolymers are fashioned with a high control over molecular weight and without the need for post-polymerization procedures. The homopolymers undergo fast and efficient self-assembly with their complement homopolymer or small molecule analogue to form block-copolymer architectures. The block copolymers show equivalent association constants as their small molecule analogues described in the literature, regardless of size or nature of the complementary unit or the polymer side chain. 相似文献
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S. Yang H. X. Xiao D. P. Higley J. Kresta K. C. Frisch W. B. Farnham 《高分子科学杂志,A辑:纯化学与应用化学》2013,50(2-3):241-252
Abstract Various amounts of fluorine-containing polyol (F-diol, MW = 3700) were introduced into the soft segment of anionic aqueous polyurethanes (PUs) to examine the effect of the F-diol on the properties of the anionic aqueous PUs. The hard segments in the anionic aqueous PUs consisted of 4,4′-methylene bis(cyclohexylisocyanate), dimethylolpropionic acid, and 1,4-cyclohexanediamine (cis/trans = 80/20). Both the mechanical and water resistance properties of the anionic aqueous PUs were improved after introducing small amounts of the F-diol in the soft segment of the aqueous PUs. This is due to the increased intermolecular forces and crystallinity as well as the hydrophobic characteristic of the F-diol. Thermal analysis of the F-diol modified anionic aqueous PUs by differential scanning calorimetry and dynamic mechanical analysis indicated that both intermolecular forces and crystallinity increased with increasing concentration of the F-diol. However, both the increased intermolecular forces and crystallinity could have an adverse effect on the interface adhesion. 相似文献
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In order to determine physical location of contaminants in soil, solidified soil "thin" sections, which preserve the undisturbed structural characteristics of the original soil, containing weapons-grade plutonium from Rocky Flats Environmental Test (RFETS), were prepared. Two autoradiographic methods were used in radionuclide mapping, contact autoradiography using CR-39® plastic alpha-track detectors and neutron-induced autoradiography that produced fission fragment tracks in Lexan® plastic detectors. The combination of the two autoradiographic methods allowed to distinguish alpha-emitting particles of natural U, 239+240Pu and non-fissile alpha-emitters. ocations of 990 alpha "stars" caused by 239+240Pu and 241Am "hot particles" were recorded, particles were sized, their size-frequency and depth distributions were analyzed. Several large colloidal conglomerates of 239+240Pu and 241Am "hot particles" were found in soil profiles. 相似文献