Ionic gelators: oligomeric and polymeric electrolytes as novel gel forming materials

In this article, novel gel‐forming materials based on oligomeric and polymeric electrolytes for not only water but also organic solvents, including ionic liquids, are highlighted especially the synthesis, derivatization, and physical property. The oligoelectrolytes with cationic pyridinium backbone can be very easily prepared by the intermolecular quaternization of the ampholytic monomer. The ionene polymers with N,N′‐(p‐phenylene)dibenzamide linkages as polyelectrolyte were also straightforwardly synthesized in high yields by the copolymerization of 1,4‐bis[4‐(chloromethyl)benzamide]benzene and commercially available α,ω‐ditertiary amines. The oligo‐ and polyelectrolytes provided physical hydrogels under ca. 1–5 wt% of the concentrations after heating and cooling at room temperature without any other additives. These cationic gelators have characteristic properties, such as acid resistance, a self‐healing nature after mechanical collapse, and a dispersant ability for single‐walled carbon nanotubes, which have been rarely attainable for conventional physical gelators. © 2010 The Japan Chemical Journal Forum and Wiley Periodicals, Inc. Chem Rec 10: 230–242; 2010: Published online in Wiley InterScience ( www.interscience.wiley.com ) DOI 10.1002/tcr.201000007     

A novel biomimetic polymer as amphiphilic surfactant for soluble and biocompatible carbon nanotubes (CNTs)

Novel amphiphilic diblock copolymer, cholesterol-end-capped poly(2-methacryloyloxyethyl phosphorylcholine) (CPMPC), which has poly(2-methacryloyloxyethyl phosphorylcholine) (PMPC) as hydrophilic segment and cholesterol as hydrophobic segment, was specially designed as amphiphilic surfactant to achieve water-soluble and biocompatible carbon nanotubes (CNTs). The pristine CNTs were facilely dispersed via non-covalently binding the zwitterionic phosphorylcholine-based amphiphile onto the surfaces of the CNTs. It is interesting to find that CPMPC shows better CNTs solubilizing ability compared with the surfactant of pyrene-end-capped poly(2-methacryloyloxyethyl phosphorylcholine) (PPMPC). The biocompatibility of the CPMPC stabilized CNTs was evaluated using cholesterol-end-capped poly(2-(dimethylamino) ethyl methacrylate) (CPDMAEMA), cholesterol-end-capped poly(acrylic acid) (CPAA) and cholesterol-end-capped poly(ethylene oxide) (CPEG) as surfactants for CNTs as controls. While CPDMAEMA stabilized CNTs and CPAA stabilized CNTs showed obvious cytotoxicity, cytotoxicity of this novel zwitterionic phosphorylcholine-based amphiphile stabilized CNTs was not observed as indicated by cell culture. The biocompatible CNTs represent an excellent nano-object for potential biomedical applications.     

丙烯腈-甲基丙烯酸酯网状凝胶聚合物电解质研究

用酯化方法合成了甲基丙烯酸缩乙二醇二酯,获得了纯净样品,对合成的网状凝胶型聚合物电解质的合成条件进行了系统研究,获得了丙烯腈-甲基丙烯酸缩乙二醇二酯-增塑剂?锂盐网状凝胶电解质。通过红外光谱、核磁、DSC、TG等对丙烯腈-甲基丙烯酸缩乙二醇二酯的结构性能进行了研究。DSC测试结果表明合成的网状聚合物是非晶的,软化点温度为90℃左右,随丙烯腈与甲基丙烯酸缩乙二醇二酯的比例不同而不同。另外TG测试本电解质材料在300℃左右才分解,是理想的高温锂聚合物电池电解质材料。网状凝胶电解质在EC含量达到66%时,室温电导率可达到2.5×103S/cm。     

Glycol-assisted Cu-doped ZnS polyhedron-like structure as binder-free novel electrode materials

The facile, efficient, and straightforward preparation of electrode material for energy storage devices has drawn considerable interest for practical applications. In this study, we have synthesized the polyhedron Cu-doped ZnS (ZnS:Cu) structure on carbon cloth (CC) using a single-step glycol-assisted process. The highly interconnected polyhedron shaped ZnS:Cu functions as positive electrode material in an aqueous electrolyte for supercapacitor application. The ZnS:Cu polyhedron-like structures with higher electroactive sites and synergistic effect exhibited higher specific capacitance of 468 F g^?1 at 1 Ag^?1 and cycling stability of 890.5% after 5,000 cycles. The better electrochemical performance and higher cycling stability of ZnS:Cu can be dedicated to interconnected polyhedron-like structures, doping of Cu in ZnS, and binder-free electrode design. This underlines the potential of the Cu-doped ZnS-based supercapacitor for next-generation energy storage devices.     

A novel molecular ladder structure of Cu(II)-Ba(II) coordination polymer exhibiting ferromagnetic coupling

A novel one-dimensional ladder-like Cu-Ba compound ([Ba(H2O)3(CuL)2] x 2H2O)n (H3L = Glycylglycine, N-[1-(2-hydroxyphenyl)propylidene]), has been synthesized and structurally characterized; it exhibits ferromagnetic interaction.     

Modular domain structure: a biomimetic strategy for advanced polymeric materials

A long lasting challenge in polymer science is to design polymers that combine desired mechanical properties such as tensile strength, fracture toughness, and elasticity into one structure. A novel biomimetic modular polymer design is reported here to address this challenge. Following the molecular mechanism used in nature, modular polymers containing multiple loops were constructed by using precise and strong hydrogen bonding units. Single-molecule force-extension experiments revealed the sequential unfolding of loops as a chain is stretched. The excellent correlation between the single-molecule and the bulk properties successfully demonstrates our biomimetic concept of using modular domain structure to achieve advanced polymer properties.     

A novel polyacrylonitrile-based porous structure gel polymer electrolyte composited by incorporating polyhedral oligomeric silsesquioxane by phase inversion method

A novel polyhedral oligomeric silsesquioxane (POSS) composite polyacrylonitrile (PAN)-based porous structure gel polymer electrolyte (GPE) is prepared by phase inversion method. The POSS additive filler is firstly obtained in the dehydration condensation reaction of vinyltrimethoxysilane (VTMS) and 3-methacryloxypropyltrimethoxysilane (MPTMS). The composition and structure of synthetic POSS and the prepared POSS composite PAN-based GPEs are investigated. It is found that compared with pure PAN-based GPE, the POSS composite PAN-based GPE with 8 wt.% POSS presents the homogeneous pore distribution and abundant electrolyte uptake (540.4 wt.%), which endows GPE-8% with the excellent comprehensive performances: the highest ionic conductivity of 2.62?×?10^?3 S cm^?1 at room temperature, the higher lithium ion transference number of 0.38, the good compatibility with lithium anode, and the higher electrochemical stability window of 5.7 V (vs. Li/Li⁺). At 0.2 C, the GPE-8%-based lithium ion battery produces a satisfactory discharge capacity of 140 mAh g^?1.

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Polyimide gel polymer electrolyte-nanoencapsulated LiCoO2 cathode materials for high-voltage Li-ion batteries

We demonstrate a novel and facile approach to surface modification of high-voltage charged LiCoO₂, which is based on encapsulating LiCoO₂ by a polyimide (PI) gel polymer electrolyte layer. The PI is introduced onto the LiCoO₂ by thermally curing 4-component (pyromellitic dianhydride/biphenyl dianhydride/phenylenediamine/oxydianiline) polyamic acid. The PI nanoencapsulating layer features the high surface coverage, nanometer thickness, and facile ion transport. These unique characteristics are expected to enable the PI coating layer to effectively suppress the undesirable interfacial reaction of the LiCoO₂ with liquid electrolyte, which plays a key role in noticeably improving the 4.4 V cycle performance and mitigating the vigorous exothermic reaction between the charged LiCoO₂ and liquid electrolyte.     

Preparation and properties of ZnMoO4 anode materials with polymer network gel method

Polymer network gel method combines the advantages of solid-phase method and liquid phase method, triggering acrylamide (AM) radical polymerization in aqueous solution and N, N′- methylene bis acrylamide (MBAM) active double bond cross-linking reaction, forming polymer chains to form a three-dimensional network. The polymer network space formed by the gel is bound and evenly distributed to the ions in the solution, thereby reducing the contact and aggregation of molecules and achieving the purpose of uniform particle size and small particle size. The principle diagram of network gel is shown in Figure. Using cubic zinc acetate and ammonium molybdate tetrahydrate as raw materials, cubic ZnMoO₄ negative electrode materials were prepared with polymer network gel method. The polymer network gel method has various effects on the structure, morphology and electrochemical properties of materials. Besides, the calcination temperature and calcination time were also the key factors to the electrochemical properties of the materials. In this paper, the effects of the ratio of monomer and crosslinker, calcination temperature and calcination time on ZnMoO₄ materials were studied by single variable method, the preparation process was optimized, and its characterization and electrochemical tests were carried out. After 100 cycles, the optimized ZnMoO₄ electrode has a discharge capacity of 374.0 mAh· g^?1, 332.5, 263.5 and 177.1 mAh · g^?1 at current densities of 0.1, 0.5, 1.0 and 2.0 A g^?1, respectively. The electrochemical results show that the optimized ZnMoO₄ has high capacity, large rate capability and excellent cycle stability.     

Creation of novel polymer materials by processing with inclusion compounds

The processing of polymer materials from their inclusion compounds (ICs) formed with urea (U) and cyclodextrin (CD) hosts is described. Several examples are presented and serve to demonstrate the fabrication of unique polymer‐polymer composites and blends, including intimate blends of normally incompatible polymers, and the delivery of additives to polymers by means of embedding polymer‐ or additive‐U and CD‐ ICs into carrier polymer films and fibers, followed by coalescence of the IC guest, or by coalescence of two polymers or a polymer and an additive from their common CD‐IC crystals.     

高分子手性固定相的研究进展

手性药物的应用对人类健康产生了深远影响。随着化学、材料、生命等学科的发展,人们对手性药物分离分析的研究日趋深入。色谱法在手性药物分离分析中得到了广泛应用,手性固定相的选择是实现手性色谱拆分的关键。以高分子材料作为手性固定相并对其进行衍生以优化手性分离性能是近些年的研究热点。本文介绍了近几年高分子手性固定相在手性分离中的研究进展,并对其发展前景进行了展望。     

Hemoglobin-imprinted polymer gel prepared using modified glucosamine as functional monomer

A new functional glycomonomer was obtained from modified glucosamine. Hemoglobin-imprinted polymer gel was prepared with allyl-bromide modified glucosamine as functional monomer, poly（ethylene-glycol）diacrylate （PEGDA） as cross-linker and ammonium persulfate [（NHn）2S2O8]/sodium hydrogen sulfite （NaHSO3） as initiators in a phosphate buffer. The adsorption capacity and selective adsorption of the molecular imprinting polymer （MIP） were also discussed.     

Changes of supermolecular structure of polymer materials at various processings

The DSC method is found convenient for the routine use in the control of changes of the supermolecular structure induced in polyethylene by treatment under various thermo-mechanical conditions. Heating and stretching of the samples act complementarily causing rearrangement of the structure, measurable even at low deformation (λ = 1.5), and below melting temperature.     

New polymer materials with controlled nanoporous structure based on N-vinylpyrrolidone

The polymer networks with nanoporous structure were obtained by the crosslinking free-radical copolymerization of N-vinylpyrrolidone with triethylene glycol dimethacrylate in bulk in the presence of amphiphilic copolymer and its fractions as templates. The templating agents consisted of copolymer or their fragments with similar monomer units and different molecular weight. Macromolecular templates were shown to be removed from the polymer composite by PrⁱOH leaving the pores. The values of the specific surface areas, the total pore volumes, pore size, and pore size distribution were measured by the method of low-temperature nitrogen absorption. The maximum value of the specific surface area was calculated to be ~26 m² g^–1. The value was significantly higher than that for the usual copolymer network. The relationship between specific surface area, parameters of pores, and macromolecular structure of template has been established. It is shown by Brunauer—Emmett—Teller method that the macromolecules having a branched architecture are more effective for the preparation of the polymer network with more developed specific surface area and narrow pore size distribution.

     

Surlyn®/titanate hybrid materials via polymer in situ sol–gel chemistry

Acid form Surlyn®/titanate hybrid materials were achieved by polymer in situ sol–gel reactions for a titanium alkoxide monomer. Atomic force microscopic images revealed arrays of titania nanoparticles having diameters of 10–30 nm. Fourier transform infrared spectra verified the presence of an internally polymerized titanate phase although unhydrolyzed TiOR groups were present. Carboxylic acid dimerization was complete at room temperature, but carboxylate anions appeared at higher titanate levels. The methylene rocking doublet persisted upon incorporation of the inorganic component, which supported the idea of largely undisrupted crystallinity. Thermogravimetric analysis showed that the degradation onset temperature of each hybrid is largely unaffected by the presence of the inorganic filler, which is consistent with the concept of an isolated titanate phase. The first‐scan differential scanning calorimetric thermogram for unfilled Surlyn® revealed the usual twin‐melting endotherms. In contrast, the primary, high‐temperature melting endotherm was seen on the first scan for the Surlyn®/titanate hybrids, but the lower temperature endotherm was either not present or weak. Primary melting persisted after several cycles of heating above the melting temperature followed by cooling, demonstrating that primary crystallinity persisted despite titanate phase incorporation. © 2002 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 11–22, 2003     

Rational design of biomimetic molecularly imprinted materials: theoretical and computational strategies for guiding nanoscale structured polymer development

In principle, molecularly imprinted polymer science and technology provides a means for ready access to nano-structured polymeric materials of predetermined selectivity. The versatility of the technique has brought it to the attention of many working with the development of nanomaterials with biological or biomimetic properties for use as therapeutics or in medical devices. Nonetheless, the further evolution of the field necessitates the development of robust predictive tools capable of handling the complexity of molecular imprinting systems. The rapid growth in computer power and software over the past decade has opened new possibilities for simulating aspects of the complex molecular imprinting process. We present here a survey of the current status of the use of in silico-based approaches to aspects of molecular imprinting. Finally, we highlight areas where ongoing and future efforts should yield information critical to our understanding of the underlying mechanisms sufficient to permit the rational design of molecularly imprinted polymers.     

A novel gel polymer electrolyte based on lithium salt with an ethyl cellulose

A novel gel polymer electrolyte (GPE) that contains Li⁺ ions was fabricated. An appropriate amount of ethyl cellulose (EC) was added to 1 M lithium perchlorate in propylene carbonate to prepare the GPE. The ionic conductivity (σ) of the GPE depends on the EC content, and the GPE with an EC content of 4.5 wt.% exhibits a maximum σ of 6.47 mS/cm, a viscosity of 141 mPa?s, and a transmittance of over 80% (visible region) at room temperature. High σ and transparent GPE can be obtained. In this work, the EC was used as natural thickener to enhance the viscosity of the liquid-state electrolyte and could improve the leakage of electrolyte solution.     

Cyclic oligoesters as potential materials for polymer nanocomposite production

Publications dedicated to cyclic oligoesters based on cyclic butylene terephthalate were analyzed and summarized. The features of their preparation and structure and their properties were considered with a special focus on advantages and disadvantages of the methods of their preparation: polycondensation at high dilution and depolymerization. The prospects of application of cyclic butylene terephthalate for polymer nanocomposite production were demonstrated. A development strategy for this research area was suggested.

     

Fabrication and activity of silicate nanoparticles and nanosilicate-entrapped enzymes using polyethyleneimine as a biomimetic polymer

In nature, some peptides induce precipitation of silicic acid into silica nanoparticles such as is found in marine algae called diatoms. However, polybasic polymers can act as peptide mimics; one such polymer, polyethyleneimine (PEI), has the advantage that it is stable at room temperature and is inexpensive, in comparison with synthetic peptides. We describe the fabrication and characterization of biosilicate nanoparticles formed by mimicking the peptides using PEI. Brownian motion nanoparticle tracking analysis and field emission gun scanning electron microscopy have been used for the first time to characterize nanoparticles made with tetramethyl orthosilicate (TMOS) and PEI to investigate the fundamental factors that affect particle properties. These factors include the effect of phosphate concentration, PEI molecular weight, TMOS concentration, and species of alkoxy-silane used. The properties of the particles are compared with other particles made with polymers that induce silication. Our results show that using PEI gives differences in particle size compared with previous work using other polymers that induce silication. The entrapment of enzymes during the silication process, rationale for using nonphosphate and phosphate buffers during enzyme entrapment, and the analysis of enzyme activity are also presented. Because enzymes can be entrapped during fabrication, it means that there are many future possibilities for the use of silicate nanoparticles containing enzymes, such as biosensors and biocatalytic reactors.     

Enhanced self-healing driving force in polymer materials by regulating molecular structure

For self-healing polymers, obtaining excellent healing ability and mechanical properties usually need complex chemical structure, external healing conditions, and high manufacturing difficulty. Therefore, self-healing efficiency and rate, mechanical strength, and simple structure design as well as no additional healing conditions of the material are contradictory properties and are difficult to optimize simultaneously. Herein, self-healable thermoplastic poly (urethane urea) elastomers driven by surface energy were fabricated by the introduction of asymmetric alicyclic structures and the healing properties in polymers were optimized by regulating surface energy. The results showed that with the increasing of isophorone diamine contents, the surface energy driving force increased from 36 kPa to 149 kPa, the healing time decreased from 30d to 5d, and healing efficiency, and tensile strength reached 100.9% and 4.04 MPa at room temperature. At the same time, polymers also obtained a high healing efficiency under high-temperature healing conditions. The healing mechanism is that asymmetric alicyclic structures with steric hindrance and ring flip promote the dissociation of hydrogen bonds, provide sufficient chain mobility, decrease the junction density, and improve the surface energy as well as the dissociation and reconstruction of hydrogen bonds. Energetic polymer composites using thermoplastic poly (urethane urea) elastomers as matrix obtained excellent healing properties. This study will offer a novel healing approach for developing advanced self-healing polymer materials.