Moon Jeong Park

We establish a new systematic methodology for controlling the water retention of polymer electrolyte membranes. Block copolymer membranes comprising hydrophilic phases with widths ranging from 2 to 5 nm become wetter as the temperature of the surrounding air is increased at constant relative humidity. The widths of the moist hydrophilic phases were measured by cryogenic electron microscopy experiments performed on humid membranes. Simple calculations suggest that capillary condensation is import

Phase behavior of poly(styrenesulfonate-methylbutylene) (PSS-PMB) block copolymers was studied by varying molecular weight, sulfonation level, and temperature. Molecular weights of the copolymers range from 2.9 to 117 kg/mol. Ordered lamellar, gyroid, hexagonally perforated lamellae, and hexagonally packed cylinder phases were observed in spite of the fact that the copolymers are nearly symmetric with PSS volume fractions between 0.45 and 0.50. The wide variety of morphologies seen in our copoly

The effect of alignment of proton-conducting domains in hydrated poly(styrenesulfonate-b-methylbutylene) copolymer films on conductivity was studied by impedance spectroscopy. Pressing isotropic samples obtained by casting results in lamellae aligned in the plane of the film. Application of electric fields and flow fields on the isotropic samples results in lamellae aligned perpendicular to the plane of the film. The alignment of lamellae, quantified by a combination of two dimensional small ang

Abstract The global energy crisis and an increase in environmental pollution in the recent years have drawn the attention of the scientific community towards the development of efficient electrochemical devices. Polymers containing charged species have the potential to serve as electrolytes in next‐generation devices and achieving high ion transport properties in these electrolytes is the key to improving their efficiency. In this article, we explore ways to improve the ion transport properties

Abstract Pressing challenges facing future lithium batteries include the realization of a high specific capacity, reliable cycle life, fast charging, and improved safety. Herein, cutting‐edge lithium–sulfur batteries based on sulfur‐rich polymers that demonstrate a high discharge capacity of 1346 mAh g −1 at 0.1C, a record‐high rate performance of 833 mAh g −1 at 10C, and long lifetime of 500 cycles with a low capacity decay of 0.052% per cycle are reported. These are realized via the linker‐con

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 o

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 (<3 V) as compared to those of electronic EAP actuators (usually kilovolts). This paper presents a brief overview of the recent progress in a range of EAP actuators by focusing on low voltage o

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 alpha- or omega-functionalized telechelic polymers with strongly associative interactions is connected to their unique supramolecular self-assembly behavior in homopolymers and ble

Lawsone (2‐hydroxy‐1,4‐naphthoquinone), a naturally derived red‐orange dye, is investigated as a promising cathode material for next‐generation lithium batteries. Lithium cells based on lawsone cathode display a high discharge capacity of 280 mA h g −1 (99% theoretical capacity), a high energy density of 664 W h kg −1 , and long life of 1000 cycles at 0.5 C along with good rate performance up to 5 C. These results represent significant improvements from previously reported organic cathode materi

We present a facile synthetic route toward binder-free, highly-dispersed Ge nanoparticles in carbon matrices using one-step pyrolysis of self-assembled Ge-polymer hybrids. 3-Dimensionally arranged Ge-carbon exhibits remarkably enhanced cycling properties and rate capability compared with carbon sheathed Ge lacking organization.

A single concentration solution (36 vol %) of a symmetric polystyrene-block-polyisoprene, total molecular weight 30 000, in the styrene-selective solvent diethyl phthalate shows a remarkably rich sequence of thermotropic order−order transitions (OOT). A combination of small-angle X-ray scattering measurements both under quiescent conditions and after shear orientation, supplemented with rheology and static birefringence, indicates the following phase sequence. At room temperature the solution ad

Block copolymer self-assembly affords diverse nanostructures, spanning from spheres and cylinders to networks, offering meticulous control over properties and functionalities at the nanoscale. However, creating thermodynamically stable network structures with high packing frustration remains a challenge. In this study, we report a methodology to access diverse network structures such as gyroid, diamond, and primitive phases from diblock copolymers using end group and linker chemistry. The stabil

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-ethylen

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 compromisin

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. Fu