Polymeric ionic liquids: Broadening the properties and applications of polyelectrolytes

The introduction of new ionic moieties, cations and anions, is extending the properties and classical applications of polyelectrolytes. These new polyelectrolytes are being named polymeric ionic liquids (PILs) in analogy to their monomeric constituents (i.e. cations such as imidazolium, pyridinium, pyrrolidonium and anions such as hexafluorophosphate, triflates, amidotriflates). This is giving rise to a new family of functional polymers with particular properties and new applications. The first part of this review will focus on the synthetic aspects of PILs and the main aspects related to their physico-chemical properties. In the second part we will review the new technological applications of these polymers such as polymer electrolytes in electrochemical devices, building blocks in materials science, nanocomposites, gas membranes, innovative anion sensitive materials, smart surfaces, and a countless set of applications in different fields such as energy, environment, optoelectronics, analytical chemistry, biotechnology or catalysis.     

基于全球专利信息的离子液体领域发展态势分析

当前世界各国对环境保护和绿色发展的重视程度日益提升,离子液体因其优良的理化性能和可设计性,在能源、材料以及环境等众多领域展现出广阔的应用前景.基于全球专利信息,对离子液体领域三类热点应用,包括CO2捕集及利用、电化学储能和生物质转化利用的全球专利申请趋势、申请地域、重要专利权人、重点技术等情况进行国内外的比较研究.研究...     

Research Progress in Frontiers of Poly(Ionic Liquid)s: A Review

Polymeric ionic liquids or poly(ionic liquid)s combine unique properties of ionic liquids with macromolecular characteristics. One of the spotlights of review was to identify potential areas of poly(ionic liquid)s. Due to unique combination of polymer and counterions, poly(ionic liquid)s possess tunable properties to be employed in range of advanced applications. Poly(ionic liquid)s composites have claimed relevance in energy storage/production and catalysis. In biosensors, poly(ionic liquid)s were employed to fabricate enzyme electrodes. Moreover, stimuli-responsive copolymers were used to form multi-responsive poly(ionic liquid)s. Separation membranes have been reported for gas separation/storage/transport. A significant use of poly(ionic liquid)s was found as solid-state electrolyte. In fuel cell, poly(ionic liquid)s-based electrolyte membranes were employed.     

聚离子液体及其在天然产物分离中的应用

天然产物资源丰富,其高效利用离不开先进的分离技术。兼具离子液体高选择性及聚合物安全、易回收等特性的聚离子液体为天然产物的分离提供了新途径。在介绍聚阳离子型、聚阴离子型和聚两性型离子液体制备技术的基础上,综述了使用聚离子液体的固相萃取、固相微萃取、分子印迹固相萃取、液液萃取及毛细管电泳技术在黄酮类、生物碱类、酚类、蛋白质类等天然产物分离中的研究进展,分析了聚离子液体分离作用机理及其具有良好的分离效率、稳定性和回收再利用性能的原因,特别强调了刺激响应聚离子液体在天然产物分离中的优势,并从聚离子液体设计和定制出发对聚离子液体在分离领域所存在的挑战和潜在的应用进行了展望。     

Feasibility of conducting semi‐interpenetrating networks based on a poly(ethylene oxide) network and poly(3,4‐ethylenedioxythiophene) in actuator design

A new type of synthetic pathway—the use of interpenetrating polymer networks (IPNs)—is proposed to design conducting polymer‐based actuators. Two types of materials with interesting conducting properties were prepared: (1) a semi‐IPN between poly(3,4‐ethylenedioxythiophene) (PEDOT) and branched poly(ethylene oxide) (PEO) network; (2) a tricomponent IPN between PEDOT and a PEO/polycarbonate (PC)–based network as the ionic conducting partner. In the first case, the influence of the amount of branching in the PEO network on the EDOT uptake and electrochemical properties was studied. A maximum conductivity (15 S cm^?1) was obtained for 60 wt % branched PEO in the material. Moreover, the dispersion profile of PEDOT in the material was shown by elemental analysis and energy dispersion spectroscopy to follow a gradient through the thickness of the film leading to a built‐in three‐layered device. With respect to PEO/PC materials, the best results were obtained for about 80 wt % PEO in the matrix where the material remains sufficiently elastomeric. In this case, the conductivity reaches about 1 S cm^?1 for a 10 to 30 wt % polycarbonate content. These materials are capable of reversible 45° angular deflections under a 0.5V potential difference. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 3569–3577, 2003     

Nano‐structured materials with low surface energies formed by polyelectrolytes and fluorinated amphiphiles (PEFA)

Polymer complexes formed by polyelectrolytes and fluorinated amphiphiles (PEFA) represent a new class of materials which can be prepared easily as nano‐structured coatings on a large number of chemically different substrates. The surface energies of PEFA coatings are remarkably low and can be adjusted in the range 6–18 m Jm⁻². Many of their physical properties, such as elastic modulus and mechanical strength, are determined by the nature of the polymer structure. By adjusting charge densities, molecular weights and the content of nonionic comonomers, a great variety of optimizations for a number of applications are possible. The amphiphiles have a decisive influence on the nano‐structure and on the surface energy of these materials. They act as building blocks, which vary in their number of fluorinated chains, their chain lengths and in the ionic head‐groups. Carboxylate, phosphate and sulfonate groups are preferred for the preparation of PEFAs. The scope of this review is to present a discussion of the mesomorphous structures (from columnar discotic to perforated lamellar), the low surface energies and attractive applications of these PEFA materials. Applications are found predominantly in low‐friction and anti‐soiling coatings. © 2000 Society of Chemical Industry     

聚合物制备工程陶瓷的研究概况

随着聚碳硅烷、聚硅氮烷、聚硅氧烷以及聚硅硼烷等先进前驱体材料的开发,由含硅陶瓷预制体聚合物制备的工程陶瓷在Si-O-C-N-B体系中占有重要的地位。耐高温的SiC和SiN陶瓷纤维增强陶瓷基复合材料(CMC)已在航空、航天结构中获得应用,而耐中、低温的新型涂层、单向带,泡沫和复杂形状的构件在未来将在能源、环境、运输和通讯领域占有重要的地位。综述了陶瓷预制体聚合物的合成、聚合物制备陶瓷的性能、聚合物制备陶瓷的方法以及影响聚合物热解的主要因素。     

ABTS•+ scavenging activity of polypyrrole,polyaniline and poly(3,4‐ethylenedioxythiophene)

Although many methods are available for the evaluation of the antioxidant capacity of samples presented in the liquid state, typically food and beverages, to date only the 2,2′‐diphenyl‐1‐picrylhydrazyl (DPPH) assay has been applied to the measurement of the antioxidant capacity of solid samples such as active packaging materials. A modified 2,2′‐azino‐bis(3‐ethylbenzothiazoline‐6‐sulfonic acid) diammonium salt (ABTS) assay has been successfully developed for the measurement of the antioxidant capacity of conducting polymer powders. The ABTS^?+ radical scavenging activity of polypyrrole (PPy), polyaniline (PANI) and poly(3,4‐ethylenedioxythiophene) (PEDOT) powders was compared. The ranking order for greatest antioxidant capacity among the conducing polymer powders was PANI > PPy > PEDOT. The reduced forms of all the three conducting polymer samples were found to show greater radical scavenging activity than their as‐prepared partially oxidized forms. The modified ABTS assay is a simple, rapid and sensitive method for evaluating the antioxidant capacity of conducting polymer powders. The method is also suitable for composite antioxidant materials comprising a conducting polymer and a conventional packaging polymer. Copyright © 2010 Society of Chemical Industry     

Examination of the fundamental relation between ionic transport and segmental relaxation in polymer electrolytes

Replacing traditional liquid electrolytes by polymers will significantly improve electrical energy storage technologies. Despite significant advantages for applications in electrochemical devices, the use of solid polymer electrolytes is strongly limited by their poor ionic conductivity. The classical theory predicts that the ionic transport is dictated by the segmental motion of the polymer matrix. As a result, the low mobility of polymer segments is often regarded as the limiting factor for development of polymers with sufficiently high ionic conductivity. Here, we show that the ionic conductivity in many polymers can be strongly decoupled from their segmental dynamics, in terms of both temperature dependence and relative transport rate. Based on this principle, we developed several polymers with “superionic” conductivity. The observed fast ion transport suggests a fundamental difference between the ionic transport mechanisms in polymers and small molecules and provides a new paradigm for design of highly conductive polymer electrolytes.     

Fluorinated polyphosphazene polyelectrolytes

Polyphosphazene polyelectrolytes containing various amounts of hydrophobic fluorinated moieties and ionic carboxylic acid groups were synthesized. Polymer compositions and molecular weights were characterized by NMR and gel permeation chromatography. Interestingly, poly[(carboxylatophenoxy)(trifluoroethoxy)phosphazene] containing 60 mol % fluorinated groups was found to be soluble in aqueous solutions. The behavior of fluorinated polyelectrolytes in reactions of ionic complexation with multivalent and monovalent salts was studied in aqueous solutions and ethanol–water mixtures. Such reactions led to the formation of ionotropic hydrogels under mild conditions and, thus, are of importance to the development of microencapsulation processes and controlled release formulations. All of the synthesized polymers underwent phase separation in the presence of multivalent ionic crosslinkers, such as spermine and calcium chloride. This included a water‐soluble polyelectrolyte containing 40 mol % ionic groups and hydrophobic polymer with only 3 mol % carboxylic acid groups. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 53–58, 2007     

Poly(ethylene oxide)‐based block copolymer electrolytes for lithium metal batteries

Nanostructured block copolymer electrolytes (BCEs) based on poly(ethylene oxide) (PEO) are considered as promising candidates for solid‐state electrolytes in high energy density lithium metal batteries (LMBs). Because of their self‐assembly properties, they confer on electrolytes both high mechanical strength and sufficient ionic conductivity, which linear PEO cannot provide. Two types of PEO‐based BCEs are commonly known. There are the traditional ones, also called dual‐ion conducting BCEs, which are a mixture of block copolymer chains and lithium salts. In these systems, the cations and anions participate in the conduction, inducing a concentration polarization in the electrolyte, thus leading to poor performances of LMBs. The second family of BCEs are single‐lithium‐ion conducting BCEs (SIC‐BCEs), which consist of anions being covalently grafted to the polymer backbone, therefore involving conduction by lithium ions only. SIC‐BCEs have marked advantages over dual‐ion conducting BCEs due to a high lithium ion transference number, absence of anion concentration gradients as well as low rate of lithium dendrite growth. This review focuses on the recent developments in BCEs for applications in LMBs with particular emphasis on the physicochemical and electrochemical properties of these materials. © 2018 Society of Chemical Industry     

Thermoresponsive microhydrogels: preparation,properties and applications

A microgel is a fascinating type of soft matter. Among the various microgels, great interest has been shown in microhydrogels because their functions are realized in water, which is the most benign liquid to humans. The microhydrogel‐composing polymers have their own delicate hydrophilic ? hydrophobic balance, which is sensitive to environmental conditions such as temperature, pH, ionic strength, light and specific (bio)molecules, in many cases. This review describes the methodology for the preparation of such microhydrogels, their properties, and finally their applications in physicochemical, biological and biomedical, optical and photonic, and chemical fields. The main material cited is a representative temperature‐sensitive polymer, poly(N‐isopropyl acrylamide), but some other environment‐friendly polymers such as cellulose derivatives are also reported. © 2013 Society of Chemical Industry     

Preparation and properties of gel membrane containing porous PVDF-HFP matrix and cross-linked PEG for lithium ion conduction

Lithium ion conducting membranes are the key materials for lithium batteries. The lithium ion conducting gel polymer electrolyte membrane (Li-GPEM) based on porous poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) matrix and cross-linked PEG network is prepared by a typical phase inversion process. By immersing the porous PVDF-HFP membrane in liquid electrolyte containing poly(ethylene glycol) diacrylate (PEGDA) and an initiator to absorb the liquid electrolyte at 25°C, and then thermally cross-linking at 60°C, the Li-GPEM is fabricated successfully. The measurements on its weight loss, mechanical and electrochemical properties reveal that the obtained Li-GPEM has better overall performance than the liquid and blend gel systems used as conductive media in lithium batteries. The ionic conductivity of the fabricated Li-GPEM can reach as high as 2.25 × 10^-3 S/cm at 25°C.     

Joining of polymers and polymer–metal hybrid structures: Recent developments and trends

The development of new materials and fabrication techniques has become a matter of success for industrial sectors such as transportation. Polymers, polymeric composites, and polymer–metal structures are being increasingly employed in several products mainly due to the associated weight savings. The main joining methods for polymer and polymeric composites are mechanical fastening, adhesive bonding, and welding. On the other hand, polymer–metal structures are more difficult to join by traditional joining methods, mostly due to their strong dissimilar physical–chemical features. Constant efforts on developing improved alternative joining techniques for these hybrid structures, such as the FricRiveting and injection over molding, have contributed to the dissemination of such structures in industrial applications. This work shows that the field of joining of polymers, polymeric composites, and polymer–metal hybrid structures for industrial applications is still a growing research and development area. This is due to the increasing aspirations for more environmental‐friendly technologies and lightweight materials. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers     

Self‐Assembly and Adjustable Ion Conducting Behavior of Graphene Oxide Liquid Crystalline Network Membranes

Self‐assembly of graphene oxide liquid crystalline network (GO‐LCNs) membranes is constructed for the first time via Langmuir–Blodgett assembly technique. The GO‐LCNs are synthesized by hydrogen‐bonded self‐assembly between carboxyl groups on graphene oxide and pyridinyl groups on liquid crystalline polymers. These GO‐LCNs membranes possess distinct microstructures and show adjustable ion conducting behavior due to GO planar structure induced by mesogen oriention of liquid crystal molecules. The liquid crystalline behavior of the GO‐LCNs is identified by combining polarized optical microscopy, differential scanning calorimetry, and X‐ray diffraction measurements. The liquid crystalline properties of GO‐LCNs are adjusted by the composition of the liquid‐crystalline polymers. The microstructures and ion conducting behavior of GO‐LCNs membranes are investigated by applying different electromagnetic field, which are identified by different ionic conductivity of lithium bis(trifluoromethanesulphonyl)imide organic solution passed through the membranes. Ionic conductivity of solutions is increased nearly 100‐fold and tenfold for an orientated GO‐LCNs membrane. These GO‐LCNs are promising materials in numerous applications such as high‐performance electrode material, ion battery materials, proton conductors, and so on.     

Comb Polymer Architecture, Ionic Strength, and Particle Size Effects on the BaTiO3 Suspension Stability

We investigate the stability of aqueous barium titanate suspensions as a function of dispersant architecture, ionic strength, counterion valency, and particle size. Both pure polyelectrolytes, poly(acrylic acid) and poly(methacrylic acid) (PMAA), and comb polymer dispersants composed of a PMAA backbone with methoxy-poly(ethylene oxide) (mPEO) teeth of varying molecular weights are studied. While each dispersant imparts stability to barium titanate suspensions at low ionic strength (<∼0.01 M ), only the PMAA–mPEO comb polymer with the longest teeth provides stability at higher ionic strengths independent of particle size and counterion valency. Our findings provide new insight into the design of comb polymer dispersants for stabilizing aqueous ceramic suspensions over a broad range of processing conditions.     

Novel approaches to developing carbon nanotube based polymer composites: fundamental studies and nanotech applications

The adsorption of several types of conducting polymers on carbon nanotubes is investigated by electrical transport measurements. We report the optoelectronic properties occurring in single-walled carbon nanotubes (SWNTs) conjugated polymer, poly(3-octylthiophene), composites. Al/polymer-nanotube composite/indium-tin oxide diodes show photovoltaic behavior proposing that the main reason for this increase is the photoinduced electron transfer at the polymer/nanotube interface. Interesting results were obtained in the case of poly(o-anisidine) (POAS)-multi-walled nanotubes (MWNTs) composites where the increment of monolayers results in a significant improvement of the specific conductivity. POAS-coated MWNTs thin films demonstrated their potentiality as a new class of materials for inorganic vapors detection for environmental applications.     

含有偶氮苯结构单元的离子液体在智能材料中的应用与研究进展

刺激响应性材料作为新型智能材料,在日常生活和工业生产方面有着重要应用,但能耗高、难以精准控制及循环可逆性差限制了其使用范围。偶氮苯基团是一种合成相对简单、循环可逆性好、易于精准控制、相对节能的光敏性官能团。离子液体是一类蒸汽压低、热稳定性好、可设计、对环境污染程度较低的新型液体材料。因此含有偶氮苯基团的离子液体是一类既具有光响应性,又具有离子液体特性的新型功能材料,凭借其在紫外/可见光(UV/Vis)照射下发生光致异构化,从而引起物化性质和材料性能发生可控变化,成为目前研究的热门。本工作综述了近年来含有偶氮苯基团的离子液体在光控智能材料中的应用,对含有偶氮苯结构单元的离子液体在光控电导率、光控自组装、光控相行为、光控CO₂的捕获与释放和光响应可控离子凝胶黏弹性等领域的研究进展进行了详细介绍,并对其未来的发展方向进行了展望。含有偶氮苯结构单元的离子液体具有独特的优势,在可持续发展的大背景下能够为智能材料、绿色化学的发展提供新的思路。     

Trends in Conducting Polymer and Hybrids of Conducting Polymer/Carbon Nanotube: A Review

Several conducting polymers, including polyaniline, polypyrrole, polythiophene, polyvinylpyrrolidone, poly(3,4-ethylenedioxythiophene), poly(m-phenylenediamine), polynaphthylamine, poly(p-phenylene sulfide), and their carbon nanotube reinforced nanocomposites are discussed in this review. The physical, electrical, structural and thermal properties of polymers along with synthesis methods are discussed. A concise note on carbon nanotubes regarding their purification, functionalization, properties and production are reported. Moreover, the article focuses upon synthesis methods, properties and applications of conducting polymer/carbon nanotube nanocomposites are focused. Nanotube dispersion, loading concentration and alignment within conducting polymer/carbon nanotube nanocomposite affect their performance and morphology. The conducting polymer/carbon nanotube nanocomposites are substantially used in sensors, energy storage devices, supercapacitors, solar cells, EMI materials, diodes, and coatings.     

Novel actuators based on polypyrrole/carbide-derived carbon hybrid materials

Polypyrrole (PPy) hybrid films incorporated with porous carbide-derived carbon (CDC) particles are synthesized through a novel one-step electrochemical synthesis process that provides a simple and efficient alternative for current tape-casting and inkjet printing technologies to make conducting polymer–CDC-based electroactive composites. The resulting porous, robust and electrically conductive hybrid layer was used to fabricate electroactive polymer actuators both as perpendicularly expanding actuators and as bending trilayer actuators. Raman and FTIR spectroscopy confirm successful incorporation of CDC in the PPy matrix. Cyclic voltammograms confirm slightly higher charging/discharging currents of the PPyCDC hybrid. This indicates the successful coupling of CDC in order to increase electric double-layer capacitance in the hybrid films. The maximum steady state electromechanical diametrical strain is 13% for hybrid material which is in the same order of magnitude as for PPy and 10× more than previously reported CDC films made with non-conducting polymer binders. Furthermore, the expanding actuators made from hybrid material are more efficient than non-modified PPy actuators, having doubled the amount of swelling per injected charge. This improvement is very important since the low energy efficiency is a major shortcoming for ionic electroactive polymers. The high pseudocapacitance makes these new hybrid materials also interesting for energy storage applications.