A series of π‐conjugated polymers linked by benzocarborane (1,2‐(buta‐1′,3′‐diene‐1′,4′‐diyl)‐1,2‐dicarbadodecaborane) were synthesized via Sonogashira–Hagihara polycondensation reaction. The opened molecular structure of diiodo monomer containing benzocarborane resulted in fast polymerization and high molecular weights. The obtained polymers were fully characterized by 1H, 13C, and 11B NMR spectroscopies. UV‐vis absorption and photoluminescence studies revealed the acceptor‐profile of benzocarborane. Unlike the polymers linked by o‐carborane, these polymers exhibited strong luminescence in the solution state, presumably because the inductive effect of carborane is dominant, rather than cage‐π interactions.
A fast method is presented for the calculation of the MSD and the MWD of polymers obtained via step‐growth polymerization of polyfunctional monomers bearing identical reactive groups (i.e., systems of type “Afi”). Using this method, the complete distribution can be calculated rapidly, not just the statistical averages of the polymer population such as or . The computed MSD and MWD give more insight than these averages and can be compared to similar data measured on actual polymer systems. The low‐ and intermediate molecular size/weight part of the distribution curves are calculated using a recurrence scheme, while the high‐molecular tail (large and very large polymers) of the distributions is derived from an asymptotic approximation of the associated generating functions.
Two emerging material classes are combined in this work, namely polymeric carbon nitrides and microporous polymer networks. The former, polymeric carbon nitrides, are composed of amine‐bridged heptazine moieties and showed interesting performance as a metal‐free photocatalyst. These materials have, however, to be prepared at high temperatures, making control of their chemical structure difficult. The latter, microporous polymer networks have received increasing interest due to their high surface area, giving rise to interesting applications in gas storage or catalysis. Here, the central building block of carbon nitrides, a functionalized heptazine as monomer, and tecton are used to create microporous polymer networks. The resulting heptazine‐based microporous polymers show high porosity, while their chemical structure resembles the ones of carbon nitrides. The polymers show activity for the photocatalytic production of hydrogen from water, even under visible light illumination.
Attachment of triarylamino‐functional groups at the 9‐position of 2,7‐linked carbazole polymers results in blue‐emitting materials with two independent redox processes that were attributed to the triarylamino groups and the polymer backbone, respectively. This new class of blue‐emitting conjugated polymers was prepared via a Suzuki cross‐coupling reaction and showed low turn‐on voltages in electroluminescent devices as a result of their low ionisation potentials. The photophysical, electrochemical and electroluminescent properties of these materials are discussed.
A new π‐conjugated charge‐transfer‐type copolymer of electron‐donating thiophene and electron‐accepting quinoxaline was prepared by organometallic polycondensation. The polymer was soluble in organic solvents such as tetrahydrofuran, and showed a UV‐vis peak at long wavelengths of 598 nm in chloroform and 629 nm in the film. Its film exhibited a χ(3) peak in the resonance region with a χ(3) value comparable to that of regioregular head‐to‐tail poly(3‐hexylthiophene‐2,5‐diyl).
Amphiphilic hybrid π‐conjugated polymers that have polyhedral oligomeric silsesquioxanes on their side chains have been successfully synthesized by the Sonogashira–Hagihara polycondensation reaction. The obtained polymers were studied with ultraviolet‐visible absorption and photoluminescence spectra. In these polymers, the π‐conjugation length was extended along the poly(p‐phenylene‐ethynylene) backbone. Furthermore, the content of the POSS substituents can influence the aggregation behavior of the polymers and subsequent luminescent properties.
PANI nanofibers are prepared electrochemically by template‐free method on a stainless steel electrode. Both the hydrophilicity and the lipophilicity of the modified SS surface are enhanced by the nanostructured PANI, and a super‐amphiphilic surface is obtained in this way. The influence of polymerization conditions, such as polymerization potentials, polymerization time, the acidity, and the dopants on the super‐amphiphilic property, has been systematically investigated. In addition, the mechanisms of obtaining a super‐amphiphilic surface are briefly discussed.
Porous polymeric monoliths were prepared via electron beam triggered free radical polymerization of (meth)acrylates. Post‐synthesis functionalization of these supports was accomplished via electron beam initiated free radical graft polymerization of methacryloyl‐substituted NHC precursors. The grafted precursors were converted into the corresponding copper complexes. Cu‐loadings were between 1.3 mg · g−1 and 1.5 mg · g−1. These supported catalysts were used in selected CO hydrosilylation and cyanosilylation reactions using a continuous flow setup.
Phosphorescent conjugated polymers consisting of alternating p‐phenylene‐ethynylene and ‘para‐’ or ‘meta‐type’ Pt(II)‐salphen luminophore units have been synthesized. Side‐arms bearing different substituents (n‐alkoxy and acetylated‐sugar) have afforded contrasting emission properties that are attributed to the polymer conformation, extent of π‐stacking interactions and differences in chemical structure. Intriguing selectivity in luminescent sensing of metal ions has been observed.
Here, we report the use of fluorescently labelled proteins to study protein adsorption to microarrayed synthetic polymers for the first time, indicating that this method is appropriate for the study of protein adsorption on these arrays. To investigate protein adhesion directly we use atomic force microscopy (AFM) to measure the force of adhesion between a protein‐coated probe and the arrayed polymers. Both approaches show promise as methods for screening protein interactions with polymers in a microarray format. Comparison of these very different measures of protein–surface interactions indicate a good correlation.
Perfectly alternating copolymers can be synthesised by reacting diacrylates with terminal dienes using alternating diene metathesis polycondensation (ALTMET). This novel method is very versatile and allows preparation of diverse structures of polymers, including main‐chain liquid crystalline polymers.
Main‐chain liquid crystalline polymer obtained by ALTMET. 相似文献
This study reports a continuous prepartion of spherical or hemispherical polymer particles simply utilizing the phase separation in polymer blend films during the coating process. We took an advantage of the strong phase separation between a water‐soluble crystalline polymer as a matrix and hydrophobic polymers as minor components. We demonstrated the prepartion of water‐soluble polystyrene (PS) particles, nitrilotriacetic acid (NTA)‐functionalized PS particles for protein separation, and semiconducting poly(3‐hexylthiophene) (P3HT) particles. The sizes of the particles could be controlled by adjusting the film thickness and weight fraction of the minor component polymers in the blend film. It provides a simple facile way to prepare polymer particles in a continous process.
Phage therapy by oral administration requires enhanced resistance of phages to the harsh gastric conditions. The aim of this work is the microencapsulation of phages in natural biopolymeric matrices as a protective barrier against the gastric environment. Alginate and pectin are used as base polymers. Further emulsification with oleic acid or coating with a different biopolymer is also studied. Emulsified pectin shows the maximum encapsulation efficiency and the highest protection against acidity, leaving more than 103 active phages after 30 min exposure at pH = 1.6, and protects phage from pepsin activity (4.2 mg mL?1). Non‐encapsulated phages are fully inactivated at pH = 1.6 or with pepsin (0.5 mg mL?1) after 10 min.
The synthesis and characterization of a soluble high molecular weight copolymer based on 4,8‐bis(1‐pentylhexyloxy)benzo[1,2‐b:4,5‐b′]dithiophene and 2,1,3‐benzoxadiazole is presented. High efficiency organic photovoltaic (OPV) devices comprised of this polymer and phenyl‐C71‐butyric acid methyl ester (PC71BM) were fabricated by additive processing with 1‐chloronapthalene (CN). When the active layer is cast from pristine chlorobenzene (CB), power conversion efficiencies (PCEs) average 1.41%. Our best condition—using 2% chloronapthalene as a solvent additive in CB—results in an average PCE of 5.65%, with a champion efficiency of 6.05%.
The synthesis of cationic mono‐(6‐O‐(1‐vinylimidazolium))‐ß‐cyclodextrin with toluenesulfonate as the corresponding anion is described. Free‐radical copolymerization of the resulting host–guest complex with N‐isopropylacrylamide or N,N‐diethylacrylamide yielded copolymers showing a temperature‐controlled solubility window in water. The impact of different anionic guests and salt concentrations on solubility behavior was investigated via turbidity measurements.
A novel colorimetric and fluorometric chemosensor for Hg2+ detection based on poly(p‐phenyleneethynylene) (PPE) containing benzo[2,1,3]thiadiazole (BDT) has been developed. A highly Hg2+‐selective fluorescence quenching property in conjunction with a visible colorimetric change from yellow to violet can be observed, which indicates that PPE‐BDT can serve as a sensitive ‘naked‐eye’ indicator for Hg2+.
Summary: Fabrication of honeycomb‐patterned films from amphiphilic dendronized block copolymer (PEO113‐b‐PDMA82) by ‘on‐solid surface spreading’ and ‘on‐water spreading’ method is reported. Highly ordered honeycomb films with quasi‐horizontally paralleled double‐layered structure can be fabricated by the on‐solid surface spreading method. This work raises the possibility that such structures can be formed in amphiphilic dendronized block copolymers and extends the family of source materials.
Summary: We report the synthesis of well‐defined block copolymers by covalent coupling of hydroxy end‐functionalized polymers. Using the high volatility of the coupling agent phosgene as compared to the solvent, very high conversion (up to 96%) is obtained in a one‐pot reaction with as little as 10−5 moles of each of the reacting polymers, even without prior purification of the as‐received reagents. This has potential as an alternative to the currently practiced method of sequential living polymerization of constituent monomers, with the added advantage of direct knowledge and control over the length distribution of each block.
Coupling of end‐functionalized polymers using phosgene to form block copolymers of controlled composition. 相似文献
Cross‐linked lyotropic liquid crystal (LLC) assemblies represent a new class of polymer materials for membrane applications. These materials are formed by the phase‐segregation and self‐assembly of polymerizable amphiphiles in water into condensed ordered ensembles that can be cross‐linked in situ with retention of microstructure. The resulting LLC polymer networks have ordered, nanometer‐scale aqueous and cross‐linked organic domains, which can be used to affect gas solubility and diffusivity through the polymer to help separate molecules via the solution–diffusion mechanism. The open aqueous domains can also be used for pore transport and size exclusion with resolution on the molecular size level. The use and application potential of cross‐linked LLC assemblies as gas separation membranes, selective vapor barrier materials, and water nanofiltration and desalination membranes are presented.
