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Athanasios Skandalis Stergios Pispas 《Journal of polymer science. Part A, Polymer chemistry》2019,57(16):1771-1783
The synthesis, characterization, and postpolymerization functionalization of star copolymers by RAFT polymerization, using ethylene glycol dimethacrylate as the difunctional monomer for core formation via crosslinking, is presented in this work. The “arm first” approach was used for the synthesis of PDMAEMAnPOEGMAn double‐hydrophilic mikto‐arm stars and PDMAEMAxPLMAy amphiphilic miktoarm stars, while the “core first” approach was used for the synthesis of (PDMAEMA‐b‐POEGMA)n double‐hydrophilic star block copolymers. Methyl iodide was used as the quaternizing agent for the transformation of the star copolymers into strong cationic star polyelectrolytes, through reaction on the dimethylamino groups of PDMAEMA blocks. The stars were characterized at the molecular level by SEC and proton nuclear magnetic resonance. Preliminary light scattering experiments, using THF and H2O as the solvents, were performed in order to get information regarding the solution behavior of the novel star copolymers synthesized. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019, 57, 1771–1783 相似文献
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Nickel dithiolene complexes encapsulated in biocompatible amphiphilic diblock copolymer nanoparticles
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Eleni Vlassi George A. Mousdis Stergios Pispas 《Journal of Polymer Science.Polymer Physics》2016,54(24):2507-2513
The goal of this study is to prepare novel hybrid nanoparticles, in the form of micellar nanoparticles in aqueous media, which will combine the properties of the amphiphilic diblock copolymers (such as PEO‐b‐PPhOx and PI‐b‐PEO) with the ones of the nickel 1,2‐dithiolene (1,2‐Ni DT) complexes. The structural and morphological analysis of these nanoparticles have revealed that they can be promising for photodynamic therapy and near‐infrared (NIR) optical imaging due to their size and absorption in NIR. The micellar nanoparticles have been studied not only in aqueous solutions but also under other physiological conditions, that is, PBS and PBS‐FBS buffer solutions. Their solutions are characterized by several methods, including UV–vis spectroscopy, light scattering, and FTIR. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2016 , 54, 2507–2513 相似文献
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Jinbao Xu Weizhen Lian Stergios Pispas Guangzhao Zhang 《Journal of polymer science. Part A, Polymer chemistry》2014,52(20):2998-3003
A facile one‐pot 1,8‐diazacyclo‐[5,4,0]undec‐7‐ene (DBU) catalyzed transesterification/atom transfer radical polymerization (ATRP) strategy has been successfully developed through the combination of copper/DBU‐catalyzed ATRP and DBU‐catalyzed transesterification reactions. Well‐defined poly(methacrylate)s with various side ester groups have been synthesized by ATRP and transesterification of acyl donor 2,2,2‐trifluoethyl methacrylate with various alcohols, such as benzyl alcohol, n‐butanol, iso‐propyl alcohol, methanol, triethylene glycol monomethyl ether, propargyl alcohol, and 6‐azido‐1‐hexanol by the one‐pot process. Kinetic studies indicate that the ATRP process proceeded in a controllable manner without the interference of the transesterification reactions. Expansion of the binary system to a higher level ternary system has been successfully achieved by the combination of copper(I)‐catalyzed azide–alkyne cycloaddition, transesterification, and ATRP reactions. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 2998–3003 相似文献
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Dimitra Topouza Katerina Orfanou Stergios Pispas 《Journal of polymer science. Part A, Polymer chemistry》2004,42(24):6230-6237
Interpolymer complexes between polystyrene‐b‐poly(2‐vinylpyridine), (PS‐P2VP), and poly(methacrylic acid) (PMAA), have been studied in dioxane. Dioxane is a good solvent for PS‐P2VP copolymers but it is a nonsolvent for PMAA at room temperature. In this way noncovalent bonded micelles are formed after mixing the solutions of the polymers at 60 °C and then allowing them to cool at room temperature. Static and dynamic light scattering as well as viscosity measurements have been used to study the dependence of aggregate mass and size as a function of the molar ratio of functional groups in PS‐P2VP/PMAA mixtures, as well as temperature. Plots of apparent average molecular weight and hydrodynamic radius of the aggregates versus amine to carboxyl group ratio show a maximum at a ratio close to one. The size of the aggregates decreases at higher ratios because of the formation of more stable micelles with smaller cores. In all cases rather compact structures were formed, as evidenced by viscometry. The mass of the aggregates was found to decrease by an increase in temperature while hydrodynamic radii were increased. This was attributed to the increase of the thermodynamic quality of the solvent toward PMAA as temperature increases. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 6230–6237, 2004 相似文献
106.
Reversible Guest Binding in a Non‐Porous FeII Coordination Polymer Host Toggles Spin Crossover
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Dr. Anders Lennartson Dr. Peter Southon Dr. Natasha F. Sciortino Prof. Cameron J. Kepert Prof. Cathrine Frandsen Prof. Steen Mørup Dr. Stergios Piligkos Prof. Christine J. McKenzie 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(45):16066-16072
Formation of either a dimetallic compound or a 1 D coordination polymer of adiponitrile adducts of [Fe(bpte)]2+ (bpte=[1,2‐bis(pyridin‐2‐ylmethyl)thio]ethane) can be controlled by the choice of counteranion. The iron(II) atoms of the bis(adiponitrile)‐bridged dimeric complex [Fe2(bpte)2(μ2‐(NC(CH2)4CN)2](SbF6)4 ( 2 ) are low spin at room temperature, as are those in the polymeric adiponitrile‐linked acetone solvate polymer {[Fe(bpte)(μ2‐NC(CH2)4CN)](BPh4)2 ? Me2CO} ( 3? Me2CO). On heating 3? Me2CO to 80 °C, the acetone is abruptly removed with an accompanying purple to dull lavender colour change corresponding to a conversion to a high‐spin compound. Cooling reveals that the desolvate 3 shows hysteretic and abrupt spin crossover (SCO) S=0?S=2 behaviour centred at 205 K. Non‐porous 3 can reversibly absorb one equivalent of acetone per iron centre to regenerate the same crystalline phase of 3? Me2CO concurrently reinstating a low‐spin state. 相似文献
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Dr. Sergio Sanz Helen M. O'Connor Eufemio Moreno Pineda Dr. Kasper S. Pedersen Dr. Gary S. Nichol Dr. Ole Mønsted Dr. Høgni Weihe Dr. Stergios Piligkos Prof. Eric J. L. McInnes Dr. Paul J. Lusby Prof. Euan K. Brechin 《Angewandte Chemie (International ed. in English)》2015,54(23):6761-6764
[CrIII8MII6]12+ (MII=Cu, Co) coordination cubes were constructed from a simple [CrIIIL3] metalloligand and a “naked” MII salt. The flexibility in the design proffers the potential to tune the physical properties, as all the constituent parts of the cage can be changed without structural alteration. Computational techniques (known in theoretical nuclear physics as statistical spectroscopy) in tandem with EPR spectroscopy are used to interpret the magnetic behavior. 相似文献
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Nikos Hadjichristidis Hermis Iatrou Stergios Pispas Marinos Pitsikalis 《Journal of polymer science. Part A, Polymer chemistry》2000,38(18):3211-3234
Anionic polymerization is a powerful tool for the synthesis of a variety of model materials with well‐defined molecular characteristics. However specially designed apparatuses and appropriate high vacuum techniques are needed in order to exclude from the reaction environment all reactive contaminants with the anionic centers. This review describes the basic principles of anionic polymerization as well as detailed experimental methods for the purification of the reagents usually used for the synthesis of model polymeric materials. In addition a few examples of the synthesis of polymers with complex architecture are given. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 3211–3234, 2000 相似文献
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Stergios Pispas Apostolos Avgeropoulos Nikos Hadjichristidis Jacques Roovers 《Journal of Polymer Science.Polymer Physics》1999,37(12):1329-1335
The dilute solution properties of three (PS)8(PI)8 miktoarm (Vergina) stars were investigated by viscometry and dynamic light scattering in toluene and tetrahydrofuran (THF) (common good solvents), cyclohexane at 34.5°C (theta solvent for PS and good for PI) and dioxane at 34°C (theta solvent for PI and good for PS). Experimental intrinsic viscosity [η] and hydrodynamic radii, Rh, values in all solvents were larger for the miktoarm stars in comparison to the calculated ones using a simple model which describes the size of the copolymers as a weighted average of the sizes of the homopolymer stars with the same total molecular weight and number of arms as the copolymer. This expansion is discussed on the basis of the increased number of heterocontacts, the topological constrains imposed by the common junction point in this highly branched miktoarm architecture and the asymmetry in molecular weights of the different kinds of arms. The conformation adopted in dilute solutions can explain, to some extent, the morphological results obtained on the same materials. The ratios of viscometric to hydrodynamic radii are consistent with previous investigations on linear and star polymers and in accord with the hard sphere model. © 1999 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 37: 1329–1335, 1999 相似文献