Search

The formation of ABC triblock terpolymers through solution casting is still challenging. In this study, core–shell double gyroid network structures are fabricated via solution casting using poly(2,2,2‐trifluoroethyl methacrylate) (PTFEMA) (F)‐b‐[poly(4‐vinylpyridine) (P4VP) (P)]‐b‐[polystyrene (PS) (S)] (FPS) triblock terpolymers in N,N‐dimethylformamide (DMF). Upon heat treatment, the polymer tends to form a sphere‐in‐lamellar structure at the F/S interface. Given the solubility properties of each component in DMF, it is anticipated that the effective volume fraction of F relative to P would increase in concentrated solutions and the effective volume fraction of S would decrease. The microphase‐separated structure derived from the DMF solution consistently results in the formation of a network structure composed of a core–shell double gyroid, with F as the matrix, P as the shell, and S as the core, and their periodic lengths gradually increase to 110.8, 131.8, and 162.7 nm as increase molecular weights of PS blocks to 13.8, 20.7, and 28.8 kg mol−1. Based on the solubility properties of the polymer components highlighted in this study, the solvent selection strategy is broadly applicable to ABC triblock terpolymers featuring various polymer components, offering a more efficient avenue for fabricating core–shell double gyroid structures. [ABSTRACT FROM AUTHOR]

Herein, CoN4, CuN4, and NiN4 complexes with a 14-membered ring hexaazamacrocycle ligand H2HAM were synthesised as precursors for ORR and CO2RR catalysts via a one-pot, gram-scale synthesis procedure, which involved microwave heating for only 10 min. Detailed structures of the obtained 14MR-MN4 complex were revealed by single-crystal X-ray diffraction measurements. [ABSTRACT FROM AUTHOR]

Advancements in nanotechnology and materials science have led to an increased demand for specific material functions, preparation, and design of polymer particles with ordered internal and surface mesostructures. In this work, well‐shaped spheres of poly(2,2,2‐trifluoroethyl methacrylate)‐b‐poly(2‐vinylpyridine) with four different molecular weights are prepared by 3D confined self‐assembly. After thermal annealing, these spheres exhibit ordered internal and surface mesostructure. Analytical studies suggest that the internal mesoporous structure is formed by the microphase separation properties of the diblock copolymers, while the formation of ordered mesopores on the surface is caused by the decomposition of the PTFEMA domains under electron irradiation. Other microphase‐separated structures, such as cylindrical and lamellar ones, are observed using solution casting and non‐solution casting methods in the same diblock copolymer, indicating that the 3D confined environment induces the formation of internal ordered spherical microphase‐separated structures in the particles. [ABSTRACT FROM AUTHOR]

A facile approach to block copolymer (BCP) domain orientation control in thin films has been demonstrated by employing a BCP with liquid crystalline semifluorinated side chains by tuning the composition of the copolymers of the bottom surface layer (BSL). 1H,1H,2H,2H-Perfluorodecanethiol was attached to a precursor polymer, polystyrene-block-poly(glycidyl methacrylate) (PS-b-PGMA), to obtain a novel BCP with a C8F17-containing liquid crystal (LC) side chain (PS-b-P8FMA). Anisotropic hexagonally packed cylinder domains in a bulk state were first characterized by transmission electron microscopy (TEM) and small angle X-ray scattering (SAXS). The observed morphology transition of BCPs with different fluorinated side chain lengths of –CF3, –C4F9, and –C6F13 suggested the decisive effects of LC side chain ordering on the anisotropic nanostructures. In the thin film study, poly(methyl methacrylate-random-2,2,2-trifluoroethyl methacrylate-random-methacrylic acid) (PMMA-ran-PTFEMA-ran-PMAA) solution was used as BSLs for tuning the desired periodicities. The surface free energy (SFE) of BSL was simply tailored by changing the composition of comonomers. In atomic force microscopy (AFM) characterization, long-range ordered perpendicularly oriented BCP domains in a hexagonally packed array or parallel oriented BCP domains as striation patterns were easily fabricated on non-preferential or preferential BSL, respectively. The study presents a novel approach to tunable thin film periodicities without changing or modifying BCPs, which is desired in next-generation BCP lithography. [ABSTRACT FROM AUTHOR]

Concentration of the salts and the charge of metal ion on swelling behavior, composition and structure of the gels poly (PAMPS) salts in aqueous medium are studied. The existence of the reentrant conformational transition in the anionic PAMPS gel is due to the increase of concentration of trivalent metal cations in the solutions.

A numerical model based on a simultaneous solution to the Nernst-Planck, Poisson, and Navier-Stokes equations is used to examine the electroosmotically driven flow through a microchannel exhibiting a periodically repeating patchwise heterogenous surface pattern.

Crystal growth and fluorescent characteristics of a quinoline-capped thiophene oligomer is investigated in thin films grown on the (001) surface of KCl by a hot-wall epitaxy technique. The cis- and trans- configurations of the quinoline groups vary the electrostatic intermolecular interactions in the solid state.

The optoelectronic properties of π‐conjugated polymers in the film state are known to be strongly affected by their structure. Inspired by this idea, the ordered‐structure‐induced electrochemical post‐functionalization (ePF) of poly(3‐(2‐ethylhexyl)thiophene) (P3EHT) films are reported. The structure of P3EHT films can be controlled by changing the solvent used to prepare them. The use of chloroform or chlorobenzene as the solvent results in amorphous P3EHT films, whereas P3EHT films with ordered structures are prepared when tetrahydrofuran is used as the solvent. The amorphous P3EHT films are not electrochemically functionalized. By contrast, ePF of the P3EHT films with an ordered structure is successful. In situ conductance measurements reveals that the successful ePF of the P3EHT films with an ordered structure originates from their greater electrochemical conductivity compared with that of amorphous P3EHT films. [ABSTRACT FROM AUTHOR]

A highly conformable long‐range ordered double gyroid structure with the space group Ia3d is obtained by the self‐assembly of a poly(2,2,2‐trifluoroethyl methacrylate)‐b‐poly(2‐vinyl pyridine) (PTFEMA‐b‐P2VP) diblock copolymer through solution casting. 9 different PTFEMA‐b‐P2VP samples are synthesized, each of which has a different mass fraction to others, with the product containing 47 wt% of PTFEMA exhibiting a double gyroid structure. Analysis of the transmission electron microscopy and scanning electron microscopy images of this product have revealed that the structural planes of the obtained 3D sample are in good agreement with the typical (211), (110), and (111) planes of the Ia3d space group, which is also supported by small angle X‐ray scattering spectroscopy, therefore confirming that the samples formed a long‐range double gyroid structure over a large area. [ABSTRACT FROM AUTHOR]

As increasingly smaller molecular materials and material structures are devised or developed for technological applications, the demands on the processes of lithography now routinely include feature sizes that are of the order of 10 nm. In reaching such a fine level of resolution, the methods of lithography have increased markedly in sophistication and brought into play 2terminology that is unfamiliar, on the one hand, to scientists tasked with the development of new lithographic materials or, on the other, to the engineers who design and operate the complex equipment that is required in modern-day processing. Publications produced by scientists need to be understood by engineers and vice versa, and these commonly arise from collaborative research that draws heavily on the terminology of two or more of the traditional disciplines. It is developments in polymer science and material science that lead progress in areas that cross traditional boundaries, such as microlithography. This document provides the exact definitions of a selection of unfamiliar terms that researchers and practitioners from different disciplines might encounter. [ABSTRACT FROM AUTHOR]

Organic field-effect transistors (OFETs) have attracted great attention as key elements in Internet-of-Thing (IoT) devices due to their advantages of low cost and mass producibility made possible by printing technology. Such devices require organic semiconductors (OSCs) that intrinsically possess high carrier mobility and air stability. In addition, the demand for low-voltage operation and low power consumption has been increasing because the potential power sources for actual devices are implementable energy harvesters that supply low power and low voltages. Based on recently developed high-performance single-crystal p-type and n-type OSCs, this work demonstrated air-stable, high-mobility OFETs with low-voltage operation by using an insulating polymer-blend printing method. By comparing two acrylic polymers poly(methyl methacrylate) and poly(adamantyl methacrylate) (PADMA), having remarkably different thermal properties, we found that PADMA showing a high glass transition temperature >200 °C was suitable for device fabrication, enhancing the flexibility of OSC materials. Also, PADMA spontaneously produced good charge-transport interfaces with the OSC single crystals, leading to high carrier mobilities of 6.6 and 2.2 cm2 V−1 s−1 in p-channel and n-channel OFETs at ≤1.5 V, respectively. The current electron mobility was the highest among low voltage-operation OFETs reported so far. These high-mobility OFETs were integrated into a complementary inverter, for which a low static power consumption of 6.6 pW was confirmed. Therefore, this study reports an advantage of polymer-blend printing for OFETs with enhanced processability and performance suitable for IoT applications. [ABSTRACT FROM AUTHOR]

Preparation of functional domains with a spacing of 10 nm is a benchmark set to fabricate next‐generation electronic devices. Organic–inorganic block copolymers form well‐ordered microphase separations with very small domain sizes. The design and preparation of a novel block copolymer consisting of syndiotactic polymethyl methacrylate (st‐PMMA) and polyhedral oligomeric silsesquioxane (POSS)‐functionalized polymethacrylate, designated as st‐PMMA‐b‐PMAPOSS, which can recognize functional molecules, are reported. The st‐PMMA segments form a helical structure and encapsulate C60 in the helical nanocavity, leading to the formation of an inclusion complex. Although the ordering of the domains is not high, C60 domains that are in a quasi‐equilibrium state, with about 10‐nm domain spacings, are generated using st‐PMMA‐b‐PMAPOSS that can recognize functional molecules. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019, 57, 2181–2189 [ABSTRACT FROM AUTHOR]

A new class of periodically nanostructured polythiophene materials with high regularity and numerous morphologies is prepared through the cooperative self‐assembly of polythiophene derivatives with a templating block copolymer (BCP) and poly(1,4‐isoprene)‐block‐poly(methacrylic acid) (PMA). The selection of the hydrophilic and aprotic triethylene glycol (TEG) group as side chains on polythiophene and the use of hydrophilic and protic PMA are crucial to producing well‐ordered nanostructures in polythiophene films, as it enables selective coassembly within the hydrophilic domain through hydrogen bonding. The composite films are shown to have formed hexagonally packed cylinders with 28 nm periodicities based on small‐angle X‐ray scattering and transmission electron microscopy. The formation of hydrogen bonding is revealed by a shift in the carbonyl peak of PMA in the Fourier transform infrared spectra of the composite film relative to the neat film. This suggests that the TEG‐functionalized polythiophene selectively incorporates into PMA. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019, 57, 1105–1112 [ABSTRACT FROM AUTHOR]

A novel organic branched phthalocyanine (Pc) dendrimer system is found that allows impressive dielectric properties with very low loss at high operational frequencies. The mechanism of this high-frequency response with relatively small dispersion is suggested to be due to a long-range polaron hopping mechanism accompanied by strong intramolecular interactions in the branched systems.

The synthesis of an n-type π-conjugated hyperbranched polymer, hyperbranched polypyridine, is described. The polymer is obtained by copolymerization of 2,4,6-tribromopyridine and 2,5-dibromopyridine via chain-growth condensation polymerization catalyzed by Ni(dppp)Cl2. The NMR and fourier transform infrared results indicate the successful introduction of the branching unit into polypyridine by this cross coupling approach. The results of UV-vis spectroscopy and cyclic voltammetry suggest that the introduction of the branching unit contributes to a quick response during electrochemical doping due to the diffusion of dopant enhanced by the hyperbranched structure. [ABSTRACT FROM AUTHOR]

Hyperbranched polyimide functionalized with 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) was studied as a heterogeneous catalyst for the aerobic oxidation of benzyl alcohol. The catalyst material was synthesized by an A2 + B3 polymerization of pyromellitic dianhydride and 1,3,5-tris(4-aminophenyl)benzene followed by an end-capping reaction with 4-amino-TEMPO. Selective aerobic oxidation of benzyl alcohol to benzaldehyde has been demonstrated using the prepared materials as a catalyst. The recyclability of these materials has been confirmed by recycling tests using the catalyst collected by filtration. [ABSTRACT FROM AUTHOR]

ABSTRACT Herein, a novel rod-coil type polyhedral oligomeric silsesquioxane (POSS)-containing diblock copolymer was designed to enable the self-assembly of hexagonally packed cylinders of the POSS-containing domain in a poly( n-butyl methacrylate) (P nBMA) matrix. When POSS-containing diblock copolymers were synthesized with polyisoprene or poly(methyl methacrylate), cylindrical structures could not be obtained as POSS-containing polymers form stretched rigid rods. This makes the formation of cylindrical structures with the POSS-containing domain entropically unfavorable. Therefore, to obtain the cylindrical structures, we constructed a novel diblock copolymer using P nBMA to increase the steric bulk and segment volume of the flexible coil. Steric crowding of the butyl groups reduces the entropic free stretching energy of the P nBMA chains, which in turn encourages the formation of a POSS-containing hexagonally packed cylindrical structure within the P nBMA matrix as the system minimizes the total free energy of the thermodynamically stable nanostructure. Small angle X-ray scattering and transmission electron microscopy analyses indicated that cylinders of the POSS domain had formed. Oxygen plasma etching was then used on the thin film to selectively remove the P nBMA domain to yield line and space structures with a high degree of long-range order and a 14 nm feature size. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017, 55, 2234-2242 [ABSTRACT FROM AUTHOR]

ABSTRACT This study demonstrates the synthesis of mesoporous carbon materials utilizing the self-assembly of a block copolymer and its electrocatalytic activity for oxygen reduction. Fine and mesoporous carbon containing ferrum (Fe) and nitrogen (N) species has been successfully synthesized by multi-step pyrolysis of a self-assembled imide film fabricated via a soft template approach. The obtained sample has well-ordered mesostructure accompanied by uniform pores with diameter of 4.8 nm and BET surface area of 1660 m2 g−1. This material is tough enough to retain its mesostructured even after mechanical ball milling, which will be essential in the application as a fuel cell catalyst. Promising catalytic activity for electrochemical oxygen reduction owing to enhanced mass transport has been demonstrated. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017, 55, 464-470 [ABSTRACT FROM AUTHOR]