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Design strategies of phosphonic acid polymers established advanced ion gels with high ionic conductivity, mechanical strength, and self-healing ability via a configurable balance of ionic and hydrogen bonding interactions at the molecular level.

A method to remove microplastics from polluted water was established through ice-assisted synthesis of polyaniline. As a result of microplastic removal, porous polyaniline nanosheets form, which can effectively filter out, detect, and capture viruses.

Recently, interest in lithium–sulfur batteries has surged due to rapid advances in energy-intensive electric devices. However, despite the high theoretical capacity, natural abundance, and environm...

Although considerable studies have focused on suppressing polysulfide shuttling in lithium–sulfur (Li–S) batteries by modifying separator surfaces, simultaneously achieving fast Li-ion transport and full active-material use remains a technological limitation. Herein, we present an effective method for anchoring zwitterionic sulfobetaine (SB) moieties on a separator surface that concurrently facilitates both selective Li-ion transport and polysulfide conversion. The platform that anchors the zwitterions was sequentially constructed by first introducing a polydopamine (PDA) coating to promote surface wettability and activity for further covalent SB binding using the aza-Michael addition reaction, which enabled the formation of a robust PDA/SB-coated separator. The zwitterion-functionalized separator exhibited a significant enhancement in ionic conductivity from 0.837 to 1.827 mS cm−1 and the Li-ion transference number from 0.186 to 0.511 due to the facile dissociation of lithium salts and selectively promoted the interactions between Li cations and the anionic sulfonate SB end groups. Along with the redox promoting effect, the polysulfide shuttling was further inhibited through strong dipole–dipole interactions. Furthermore, as Li2S precipitation was effectively mediated by the SB zwitterions and improved sulfur-conversion kinetics was achieved, outstanding Li–S battery performance with an initial discharge capacity of 1365.9 mA h g−1 was obtained, while delivering an ultra-low capacity decay rate of 0.034% during long-term cycling (up to 1200 cycles) at 3.0C, even at a high load. Therefore, we believe that the proposed study harnessing zwitterionic separator functionalization would enable the rational design of functional separators for the promoted kinetics and suppressed diffusion of unfavorable reaction intermediates for high performance batteries.

Recent advances in the synthesis of block copolymers have enabled the creation of smart and functional designer polymers possessing specific intermolecular interactions. The long-range nature of these interactions strongly affects the molecular packings and microstructures of such polymers, which are intimately related to their properties. In addition to various applications, their unique physicochemical properties, distinguished from conventional block copolymers, are attracting significant attention from polymer and materials scientists. In this review, we describe the current understanding of the structure-property relationship of block copolymers having long-range interactions and suggest possible directions of technological development. We particularly focus on how specific interactions, such as Coulombic, π-π stacking, hydrogen-bonding, and metal/ion-dipole interactions, affect the molecular arrangements of block copolymers on the nanometer and molecular scales. Such information could lead to block copolymers with more advanced functions for future nanotechnologies.

Advances in lithium battery technologies necessitate improved energy densities, long cycle lives, fast charging, safe operation, and environmentally friendly components. This study concerns lithium-organic batteries comprising bioinspired poly(4-vinyl catechol) (P4VC) cathode materials and single-ion conducting polymer nanoparticle electrolytes. The controlled synthesis of P4VC results in a two-step redox reaction with voltage plateaus at around 3.1 and 3.5 V, as well as a high initial specific capacity of 352 mAh g-1 . The use of single-ion nanoparticle electrolytes enables high electrochemical stabilities up to 5.5 V, a high lithium transference number of 0.99, high ionic conductivities, ranging from 0.2×10-3 to 10-3 S cm-1 , and stable storage moduli of >10 MPa at 25-90 °C. Lithium cells can deliver 165 mAh g-1 at 39.7 mA g-1 for 100 cycles and stable specific capacities of >100 mAh g-1 at a high current density of 794 mA g-1 for 500 cycles. As the first successful demonstration of solid-state single-ion polymer electrolytes in environmentally benign and cost-effective lithium-organic batteries, this work establishes a future research avenue for advancing lithium battery technologies.

Miktoarm star copolymers composed of three poly(ethylene oxide) (PEO) arms connected to one polystyrene (PS) chain, i.e., PS-(PEO)

The performance limits of conventional super engineering plastics with inorganic nanofillers are surpassed by all-organic nanocomposites prepared via in situ S

To fulfill the insatiable demand for wearable technologies, ionic electroactive polymer actuators have been entrenched as promising candidates that can convert low-input-voltage energy into high mechanical throughput. However, a ubiquitous trilayer design of actuators allows exclusively bending deformation and their highly nonlinear response restricts the true potential of low-voltage actuators for next-generation technology. Herein, we report an unprecedented multilayer design for soft actuators that enables complex deformations shown by skeletal muscles, mechanoreceptors, and plant roots in response to various environmental stimuli. Hierarchically ordered pores in a stretchable interlayer provide excellent electromechanical properties and fast charging kinetics, which enable linear motion by soft actuators at 3 V and under ambient conditions. Our actuators demonstrate astonishing levels of performance, including a 6.5% linear actuation strain, 0.8 s rapid switching speed, and 5000 cycle stable performance in air, producing a 4.2 mN linear blocking force at a ±3 V alternating square-wave voltage. This actuator design demonstrating a walkable spider capable of controlled back-and-forth propelling motion at low driving voltages provides the platform to envision a complex functionality using a portable battery as a power source for soft robotics, wearable exosuits, and biomimetic technologies.

The performance limits of conventional super engineering plastics with inorganic nanofillers are surpassed by all-organic nanocomposites prepared via in situ SNAr polymerization of polysulfone (PSU...

The current goal in functional polymeric material research is the preparation of polymers with high-fidelity nanoscale self-assembled structures and advanced functionality. Thus, recent research efforts have focused on linking chemistry for the development of tailor-made polymers with desired properties. The design of α- or ω-functionalized telechelic polymers with strongly associative interactions is connected to their unique supramolecular self-assembly behavior in homopolymers and blends. In addition, the end-group modification of block copolymers has shown to alter the polymer morphology radically, resulting in unprecedented property changes arising from confinement effects. This is fascinating because the content of terminal moieties is small compared to that of macromolecular polymer backbones. As an emerging theme in polymer designs and end-group chemistry, the controlled synthesis of polymers with complex architectures and functional linkages has been performed extensively in the past few decades....

The discovery of peculiar quasi-liquid layers on ice surfaces marks a major breakthrough in ice-related sciences, as the facile tuning of the reactions and morphologies of substances in contact with these layers make ice-assisted chemistry a low-cost, environmentally benign, and ubiquitous methodology for the synthesis of nanomaterials with improved functionality. Ice-templated synthesis of porous materials offers the appealing features of rapid self-organization and remarkable property changes arising from confinement effects and affords materials that have found a diverse range of applications such as batteries, supercapacitors, and gas separation. Moreover, much attention has been drawn to the acceleration of chemical reactions and transformations on the ice surface due to the freeze concentration effect, fast self-diffusion of surface water, and modulated surface potential energy. Some of these results are related to the accumulation of inorganic contaminants in glaciers and the blockage of natural gas pipelines. As an emerging theme in nanomaterial design, the dimension-controlled synthesis of hybrid materials with unprecedentedly enhanced properties on ice surfaces has attracted much interest. However, a deep understanding of quasi-liquid layer characteristics (and hence, the development of cutting-edge analytical technologies with high surface sensitivity) is required to achieve the current goal of ice-assisted chemistry, namely the preparation of tailor-made materials with the desired properties.

We examine the phase behavior of a hybrid organic-inorganic diblock copolymer/salt mixtures. The experimental system comprises poly(ethylene oxide)-block-polyhedral oligomeric silsesquioxane (PEO-POSS) mixed with a lithium bis(trifluoromethane sulfonyl) imide (LiTFSI) salt. Although the diblock copolymers without salt exhibit a classical order-to-disorder transition behavior with increasing temperature, the PEO-POSS/salt mixtures exhibit disorder-to-order transitions with increasing temperature. The analysis of a small-angle X-ray scattering data from the disordered state using Leibler's random phase approximation enables the determination of an effective Flory-Huggins interaction parameter, χ eff , for the electrolytes. Unlike conventional systems, χ eff increases with increasing temperature. A simple expression is proposed to describe the dependence of χ eff on temperature and salt concentration. This enables the calculation of the segregation strength, χ eff N, for both ordered and disordered electrolytes. The composition of the electrolytes is quantified by f EO/LiTFSI , the volume fraction of the salt-containing poly(ethylene oxide)-rich phase. The morphology of electrolytes is presented on a χ eff N versus f EO/LiTFSI phase diagram. Over the values of f EO/LiTFSI studied (0.61-0.91), only two ordered phases were found: lamellae and co-existing lamellae/hexagonally packed cylinders.

Polymerizing monomers on an atomically flat solid surface and air/water, solid/liquid, or liquid/liquid interface is now a rapidly emerging frontier. Dimension-controlled synthesis of π-conjugated polymers is of particular interest, which can be achieved by precise control of monomer distribution during the polymerization. The surface of ice allows rapid polymerization of monomers in the plane direction along the air-water interface to yield large-area two-dimensional sheet-like poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (2D sheet-like PEDOT:PSS) films with a thickness of ca. 30 nm. The persuasive role of ice chemistry is reflected in the high degree of crystallinity and superior conductivity of resultant PEDOT:PSS films. Excellent photoelectrochemical features were further disclosed when the ice-templated PEDOT:PSS films were coupled to quantum dots. Utilization of these polymer films in photovoltaic devices also resulted in excellent current density and power conversion efficiency. This work presents an innovative material technology that goes beyond traditional and ubiquitous inorganic 2D materials such as graphene and MoS2 for integrated electronic applications.

Charged block copolymers are promising materials for next-generation battery technologies and soft electronics. Although once it was only possible to prepare randomly organized structures, nowadays, well-ordered charged block copolymers can be prepared. In addition, theoretical and experimental analyses of the thermodynamic properties of charged polymers have provided insights into how to control nanostructures via electrostatic interactions and improve the ionic conductivity without compromising mechanical strength, which is crucial for practical applications. In this Account, we discuss methods to control the self-assembly and ion diffusion behavior of charged block copolymers by varying the type of tethered ionic moieties, local concentration of embedded ions with controlled electrostatic interactions, and nanoscale morphology. We discuss with particular emphasis on the structure-transport relationship of charged block copolymers using various ionic additives to control the phase behavior electrostatically as well as the ion transport properties. Through this, we establish the role of interconnected ionic channels in promoting ion-conduction and the importance of developing three-dimensional interconnected morphologies such as gyroid, orthorhombic Fddd (O70) networks, body-centered cubic (bcc), face-centered cubic (fcc), and A15 structures with well-defined interfaces in creating less tortuous ion-conduction pathways. Our prolonged surge and synthetic advances are pushing the frontiers of charged block copolymers to have virtually homogeneous ionic domains with suppressed ion agglomeration via the nanoconfinement of closely bound ionic moieties, resulting in efficient ion conduction and high mechanical strength.Subsequently, we discuss how, by using zwitterions, we have radically improved the ionic conductivity of single-ion conducting polymers, which have potential for use in next-generation electrochemical devices owing to the constrained anion depletion. Key to the improvement stems from hierarchically ordered ionic crystals in nanodomains of the single-ion block copolymers through the self-organization of the dipolar/ionic moieties under confinement. By precisely tuning the distances between ionic sites and the dipolar orientation in the ionic domains with varied zwitterion contents, unprecedented dielectric constants close to those of aqueous electrolytes have been achieved, leading to the development of high-conductivity solid-state single-ion conducting polymers with leak-free characteristics. Further, using these materials, low-voltage-driven artificial muscles have been prepared that show a large bending strain and millisecond-scale mechanical deformations at 1 V in air without fatigue, exceeding the performance of previously reported polymer actuators. Finally, smart multiresponsive actuators based on tailor-made charged polymers capable of programmable deformation with high force and self-locking without power consumption are suggested as candidates for use in soft robotics.

Significance We show the enhancement of ion transport properties for charged block copolymers comprising nonstoichiometric ionic liquids by stabilizing the cubic Frank–Kasper A15 phases. The ionic liquid cations predominantly present near the micellar interfaces to increase stabilization energies of the A15 structures if they have strong attractive electrostatic interactions with the charged polymer chains. Unprecedented reentrant phase transitions between lamellar and A15 structures occur through the electrostatic control of interfaces, resulting in radical changes in the conductivity by an order of magnitude. This study is one of the rare demonstrations of a low symmetry morphology to establish a prospective avenue for advanced polymer electrolytes having tailor-made interfaces. Our findings will have implications for energy storage and transfer devices., Recently, the interest in charged polymers has been rapidly growing due to their uses in energy storage and transfer devices. Yet, polymer electrolyte-based devices are not on the immediate horizon because of the low ionic conductivity. In the present study, we developed a methodology to enhance the ionic conductivity of charged block copolymers comprising ionic liquids through the electrostatic control of the interfacial layers. Unprecedented reentrant phase transitions between lamellar and A15 structures were seen, which cannot be explained by well-established thermodynamic factors. X-ray scattering experiments and molecular dynamics simulations revealed the formation of fascinating, thin ionic shell layers composed of ionic complexes. The ionic liquid cations of these complexes predominantly presented near the micellar interfaces if they had strong binding affinity with the charged polymer chains. Therefore, the interfacial properties and concentration fluctuations of the A15 structures were crucially dependent on the type of tethered acid groups in the polymers. Overall, the stabilization energies of the A15 structures were greater when enriched, attractive electrostatic interactions were present at the micellar interfaces. Contrary to the conventional wisdom that block copolymer interfaces act as “dead zone” to significantly deteriorate ion transport, this study establishes a prospective avenue for advanced polymer electrolyte having tailor-made interfaces.

Current technological advances and prolific endeavors have entrenched two‐dimensional conducting polymers as the rapidly emerging interface across a diversity of functional materials for flexible electronics, sensors, ion‐exchange membranes, biotechnology, catalysis, energy storage, and conversion. Rational design and fabrication of polymeric nanostructures enriched with well‐ordered geometry are appealing and endorse significant impact on their in‐built electrical, optical, and mechanical properties. In particular, recent interest in controlled hierarchical assembly of monomers/oligomers proved the free‐standing sheet‐like structures with exotic features of high conductivity and flexibility. Yet, the ongoing research to make nanometer‐thick polymers suffers from limitations to access large‐area, mechanical stability, and high‐range internal ordering. In this perspective, we focus on the radical approaches that highlight confinement‐entitled features of two‐dimensional polymeric materials correlating to their interface or template‐assisted synthesis, structure–property relationship, charge transport properties, and future scopes for relevant practical enactments. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2019, 57, 1169–1176

Polymer electrolytes are a rapidly emerging option for energy storage and conversion, water treatment, sensors, and actuators. The current scientific thrust is to develop practically viable polymer electrolytes, especially in the solid state. Toward this goal, extensive efforts have been made to prepare polymers bearing ionic moieties with various chain architectures via appropriate linking chemistry, yet challenges remain in their low ionic conductivities and/or poor mechanical strengths. This perspective begins with a summary of past and ongoing research on ion-containing polymers, peering into radical approaches that highlight the confinement-entitled features of ion-containing polymers correlating to structure–property relationships. Recent successes in tuning the nanoscale morphologies of ion-tethered polymers are stressed as significant consequences of milestones in this research era. Several emerging themes and future aims in designing ion-containing polymers are outlined for relevant practical enactments, which include end-group chemistry, single-ion polymers, fine-tuned ion clustering behavior, precise sequencing of ionic moieties, and crystalline ionic channels.

The synthesis of high-conductivity solid-state electrolyte materials with eliminated polarization loss is a great challenge. Here we show a promising potential of single-ion block copolymers with crystalline protogenic channels as efficient proton conductors. Through the self-organization of zwitterion, imidazole, and polystyrene sulfonate with controlled dipolar interactions therein, the distance between neighboring proton donors and acceptors in ionic crystals, as well as the dipolar orientation in nanoscale ionic phases was precisely tuned. This allowed a markedly high static dielectric constant comparable to water and fast structural diffusion of protons with a low potential barrier for single-ion polymers. The optimized sample exhibited a high proton diffusion coefficient of 2.4 × 10–6 cm2 s–1 under anhydrous conditions at 90 °C., High-conductivity solid-state electrolyte materials with minimal polarization loss are difficult to synthesize. Here the authors show single-ion block copolymers with crystalline protogenic channels having a promising potential to be used as efficient proton conductors.

Miktoarm star copolymers composed of three poly(ethylene oxide) (PEO) arms connected to one polystyrene (PS) chain, i.e., PS–(PEO)3, demonstrated synergistic improvements in the ionic conductivity and mechanical strength by factors of 2–30 compared to those shown by PS–PEO diblock copolymers. Entropic constraints for the chain stretching of (PEO)3 gave rise to notably reduced domain sizes of PS–(PEO)3 electrolytes, compared with the values of PS–PEO analogues. Further, the melting transition of PS–(PEO)3 with PEO molecular weight of Mn = 2 kg mol–1 was vanished with lithium salt doping at [Li]/[EO] = 0.06 under such confinements, resulting in an order of magnitude increase in the room temperature conductivity. The fact that lithium ion transport in PEO-based copolymers can be tunable by the way PEO chains are connected to hard polymers can lead to innovative designs for solid-state polymer electrolytes.

We report the controlled synthesis, self-assembly, and ion transport properties of polystyrene bisphosphonate (PSbP) and polystyrene phosphonate (PSP) based polymers, revealing that ion clustering in PSbP (characterized by precisely determined phosphonate group location) was markedly suppressed compared to that in PSP despite the 2-fold higher phosphonic acid group concentration in the former. Moreover, confinement of PSbP chains to ordered nanoscale domains in PSbP-based block copolymers offered a platform for creating nearly homogeneous ionic phases with a radically decreased potential barrier to ion conduction. Notably, the decrease in the degree of polymerization of PSbP chain in the block copolymers by half (i.e., the lower acid group contents) led to 2–3 times improved anhydrous conductivity with incorporated ionic liquids, contrary to the results commonly reported for a range of acid-tethered polymers. Our work provides a first-time demonstration of well-defined self-assembled morphologies of bisph...

Soft actuators based on electroactive polymers (EAPs) are the core constituents of future soft robots owing to their fascinating properties such as lightweight, compactness, easy fabrication into various forms, and low cost. Ionic EAP actuators are particularly attractive owing to the low driving voltages (

Organic redox-active molecules have attracted great attention for next generation electrode materials due to their promising advantages of low cost, natural abundance, environmental friendliness, and structural diversity. Here we propose a new molecular design strategy to achieve both large specific capacity and high energy organic cathode materials for Li-ion batteries using a triptycene scaffold as a minimal linker between the redox-active units. The triptycene molecule bearing three benzoquinone (BQ) units in a rigid tripod structure exhibits five-electron redox reactions that practically provide a specific capacity as high as 387 mA h g−1 in Li-ion coin cells. By combining electrochemical analyses with theoretical DFT calculations, we figure out that the 3-D arrangements of BQ units in triptycene not only facilitate a highly reversible access to a large number of redox states but also raise the redox potential. Due to the large capacity and the increased redox potential, the triptycene electrode can deliver a specific energy up to 1032 W h kg−1 at 0.1C-rate, which is close to two times the specific energy of the conventional inorganic cathode materials. It is also demonstrated that the cycling performance of triptycenes can be greatly improved by fabricating nanocomposite materials with the ordered mesoporous carbon CMK3.

Conducting polymers have been studied widely over the past decades for use as organic electrode materials owing to their high electrical conductivity and low-cost synthesis. Among the various synthesis methods reported, the recently established ice-assisted approach for developing conducting polymer nanosheets is regarded as an advanced technology that allows for easy fabrication in an eco-friendly manner. However, the role of the crystallinity of the underlying ice surface in determining the physicochemical properties of the conducting polymers remains unclear. Here, the electronic properties and packing structures of polyaniline (PANI) nanosheets formed on ice surfaces are studied by controlling the ice crystallinity. Intriguingly, the crystallinity of the PANI nanosheets resembles that of the ice surfaces, in that the anisotropic growth of the PANI crystals with a face-on orientation occurs preferentially on high-crystalline ice surfaces. In addition, it is found that the development of highly crystalline PANI nanosheets results in efficient charge transport, owing to polaron delocalization in PANI with extended chain conformations and the improvement in the degree of backbone ordering because of the preorganized aniline moieties on the ice surface.

An innovative lithium-sulfur (Li-S) battery technology is proposed that provides high energy density, fast charging, and mechanical flexibility. Via the rapid (30 min) one-pot reaction of elemental sulfur and vinyl phosphonic acid (VPA), SVPA microparticles containing dissimilar sulfur allotropes were developed. The spontaneous formation of wrinkles and pores on the particles facilitates electrolyte access and alleviates mechanical stress during battery cycling. The large surface area created by the ordered sulfur domains enhances lithium diffusion coefficients and facilitates polysulfide conversion kinetics in the Li-S cells, leading to a high discharge capacity of 1529 mAh·g−1 at 0.05 C and excellent rate performance (721 mAh·g−1 at 7 C). Additionally, owing to the inherent electrode porosity imparted by SVPA microparticles, a high areal capacity of ~5 mAh·cm−2 is obtained at increased cathode loadings. Abundant phosphonate moieties at the surfaces and interfaces of particles act as effective chemical anchors for lithium polysulfides, thereby mitigating the shuttle effects, which can prolong cycle lives at various C rates. The impressive properties of the SVPA microparticles are demonstrated for Li-S pouch cells, which exhibit stable operation under various deformations and highlight the SVPA microparticles as a promising candidate for next-generation Li-S batteries for wearable electronics

We report a new approach to the synthesis of uniform, high areal density Pt nanocrystals supported by conducting polymers. The key strategy is the use of ice-templated, two-dimensional polyaniline nanosheets at the air–water interface as a platform for expediting Pt nucleation. Highly crystalline Pt nanoparticles with a narrow size distribution of 2.7 ± 0.3 nm and a high electrochemically active surface area of 94.57 m2 g−1 were obtained. Pt NPs were strongly anchored to the polyaniline nanosheets, and demonstrated high current densities, good durability for the methanol oxidation reaction, and excellent carbon monoxide tolerance, all of which are unprecedented. The idea established in this study could be applied to the production of a wide range of other catalysts with enhanced activities.

We report a rational design of solid-state dry polymer electrolytes with high conductivity, high mechanical strength, and improved cation transference number. Thiol–ene click chemistry provided orthogonal control over the type and number of end groups in poly(styrene-b-ethylene oxide) (PS-b-PEO) block copolymers. This approach permitted the synthesis of PEO chains with reduced crystallinity, reminiscent of PEO oligomers, thereby playing a key role in improving the room temperature conductivity. Intriguingly, the incorporation of diol or dicarboxylic acid end groups in PS-b-PEO produced a well-defined gyroid structure, leading to order of magnitude improvements in the storage modulus. Out of the various samples examined, the electrolytes bearing terminal diol displayed the highest ionic conductivity and a 2-fold increase in lithium transference number. The improvements in performance are attributed to the reduced interchain aggregation and the anion stabilization mediated by the terminal diol group. The fa...

We developed a stretchable organic optoelectronic sensorimotor synapse to mimic a biological optical sensory nervous system., Emulation of human sensory and motor functions becomes a core technology in bioinspired electronics for next-generation electronic prosthetics and neurologically inspired robotics. An electronic synapse functionalized with an artificial sensory receptor and an artificial motor unit can be a fundamental element of bioinspired soft electronics. Here, we report an organic optoelectronic sensorimotor synapse that uses an organic optoelectronic synapse and a neuromuscular system based on a stretchable organic nanowire synaptic transistor (s-ONWST). The voltage pulses of a self-powered photodetector triggered by optical signals drive the s-ONWST, and resultant informative synaptic outputs are used not only for optical wireless communication of human-machine interfaces but also for light-interactive actuation of an artificial muscle actuator in the same way that a biological muscle fiber contracts. Our organic optoelectronic sensorimotor synapse suggests a promising strategy toward developing bioinspired soft electronics, neurologically inspired robotics, and electronic prostheses.

We report the facile synthesis of new naphthoquinone (NQ) derivatives for use in lithium-organic batteries to improve performance. The rational design of these NQ derivatives is based on theoretical calculations. Our lithium-organic batteries demonstrate remarkable charge–discharge properties, for example, a high discharge capacity of 250 mAh g–1 (363 mAh cm–3), discharge potential plateaus in the range of 2.3–2.5 V, and 99% capacity retention after 500 cycles at 0.2C. In particular, the batteries had excellent rate performance up to 50C with reversible redox behavior, unlike most other organic cathode materials. The key to success was a simple molecular substitution, addition of amino groups at the 2- and 3- positions of the NQ ring, yielding 2,3-diamino-1,4-naphthoquinone (DANQ). DANQ has an exceptionally low band gap of 2.7 eV and greater than 20-fold enhancement in the lithium diffusion rate compared to unmodified NQ. The fundamental shortcoming of the organic molecules, i.e., their solubility in the ...

We report the synthesis, morphology and ion transport properties of poly(styrene-b-ethylene oxide) (PS-b-PEO) block copolymers with various end-functional groups. The PS-b-PEO having an –OH terminal group showed poorly defined morphology, while the inclusion of a terminal acid unit (–SO3H or –COOH) in PS-b-PEO caused the development of an ordered lamellar structure. The terminal acid moieties in PEO were found to increase the segregation strength of PS-b-PEO and reduce the degree of crystallinity of PEO. This observation is intriguing given that the end group concentration of PEO in PS-b-PEO employed in this study is as small as 0.4 mol%. Decreased conductivity was observed for PS-b-PEO tethered with acid groups when doped with lithium salts, which we ascribe to the slow segmental motion of acid group-terminated PEO chains. However, organization of the PEO domains of PS-b-PEO with terminal acid units into self-assembled nanostructures having sharp interfaces proved beneficial for increasing ion transport efficiency by creating less tortuous ion conduction pathways. At high levels of salt loading, the thermodynamic effects of the terminal group on ion transport properties of PS-b-PEO were attenuated. Our results suggest a unique methodology for controlling the morphology and ion transport properties of block copolymer electrolytes via attachment of a single end functional unit. A unique methodology to control the morphology and ion transport properties of block copolymer electrolytes by the inclusion of functional terminal groups.

We investigated the effects of morphology on the ion transport properties of polymer electrolytes. A single sulfonated block copolymer displayed a series of ordered morphologies with three-dimensional symmetry, i.e., cubic, Fddd (O70), and Fm3m (fcc) phases, upon the addition of ionic liquids. The unique phase behavior was understood on the basis of the selective swelling of the sulfonated blocks by ionic liquids and the changes in segregation strength with the modulation of the ionic interactions in the ionic phases. The type of three-dimensional lattice was revealed to play an important role in determining the ion transport properties of ionic liquid-containing sulfonated block copolymers. For example, the sample with disordered spherical lattices exhibited the highest tortuosity (∼2) for ion conduction, indicative of the considerable diffusion barriers in the conducting phases. On the contrary, the samples with well-defined orthorhombic and face-centered cubic symmetries, i.e., O70 and fcc phases, rev...

We report the synthesis of a series of block copolymers tailored with phosphonic acid groups, poly(styrene phosphonate-b-methylbutylene) (PSP-b-PMB), which show systematic phase sequences of a disorder, lamellae, and hexagonal cylinder morphology, with controlled acid concentration. These observations were combined with the Leibler theory in order to estimate the effective Flory–Huggins interaction parameter of PSP-b-PMB, χPSP–PMB. For example, χPSP–PMB = 0.101 + 13.823/T was anticipated for the disordered phases observed at the low phosphonation level of 15 mol %. The direct comparison of PSP-b-PMB block copolymers and their sulfonated analogues, poly(styrenesulfonate-b-methylbutylene) (PSS-b-PMB), revealed a remarkably similar phase behavior. In-depth thermodynamic studies suggested similar χ values regardless of the kind of acid group when the concentration is lower than 20 mol %, whereas these values vary by increasing the amount of acid groups, as polymers carrying phosphonic acid groups showed a wea...

A new method to develop two-dimensional PANI nanosheets using ice as a removable hard template is presented. Distinctly high current flows of 5.5 mA at 1 V and a high electrical conductivity of 35 S cm(-1) were obtained for the polyaniline (PANI) nanosheets, which marked a significant improvement from previously values on other PANIs reported over the past decades. These improved electrical properties of ice-templated PANI nanosheets were attributed to the long-range ordered edge-on π-stacking of the quinoid ring, ascribed to the ice surface-assisted vertical growth of PANI. The unprecedented advantages of the ice-templated PANI nanosheets are two-fold. First, the PANI nanosheet can be easily transferred onto various types of substrates via float-off from the ice surfaces. Second, PANI can be patterned into any shape using predetermined masks, and this is expected to facilitate the eventual convenient and inexpensive application of conducting polymers in versatile electronic device forms.

We have investigated a new methodology for improving the ionic conductivity and cation transport of polymer electrolytes by incorporating an anion-stabilizing hard polymer. A lamellar-forming poly(ethylene oxide-b-dithiooxamide) (PEO-b-PDTOA) block copolymer having enhanced ion conduction and mechanical strength, arising from PEO and PDTOA, respectively, was synthesized. Compared to a simple PEO/PDTOA blend, lithium salt-doped PEO-b-PDTOA exhibited significantly enhanced ionic conductivity, which is ascribed to efficient ion transport along the nanoscale PEO domains. Strikingly, by applying a dc polarization voltage, the inclusion of PDTOA afforded a high ratio of the steady state to the initial current flow of 0.67 for the PEO-b-PDTOA electrolytes, surpassing the value of 0.31 observed for conventional PEO-salt electrolytes. A key reason for achieving enhanced cation transport was the hydrogen bonding interactions between the thioamide moieties of PDTOA and the anions of lithium salts. This work provides...

We developed a new ratiometric pH sensor based on poly(N-phenylmaleimide) (PPMI)-containing block copolymer that emits three different fluorescent colors depending on the pH. The strong solvatochromism and tautomerism of the PPMI derivatives enabled precise pH sensing for almost the entire range of the pH scale. Theoretical calculations have predicted largely dissimilar band gaps for the keto, enol, and enolate tautomers of PPMI owing to low-dimensional conjugation effects. The tunable emission wavelength and intensity of our sensors, as well as the reversible color switching with high-luminescent contrast, were achieved using rational molecular design of PPMI analogues as an innovative platform for accurate H(+) detection. The self-assembly of block copolymers on the nanometer length scale was particularly highlighted as a novel prospective means of regulating fluorescence properties while avoiding the self-quenching phenomenon, and this system can be used as a fast responsive pH sensor in versatile device forms.