Synthesis and Thermo-Responsive Behavior of Poly(-isopropylacrylamide)--Poly(-vinylisobutyramide) Diblock Copolymer.

Thermo-responsive diblock copolymer, poly(-isopropylacrylamide)--poly(-vinylisobutyramide) was synthesized via switchable reversible addition-fragmentation chain transfer (RAFT) polymerization and its thermal transition behavior was studied. Poly(-vinylisobutyramide) (PNVIBA), a structural isomer of poly(-isopropylacrylamide) (PNIPAM) shows a thermo-response character but with a higher lower critical solution temperature (LCST) than PNIPAM. The chain extension of the PNVIBA block from the PNIPAM block proceeded in a controlled manner with a switchable chain transfer reagent, methyl 2-[methyl(4-pyridinyl)carbamothioylthio]propionate.

Rational Design of Naphthol Groups Functionalized Bipolar Polymer Cathodes for High Performance Alkali-Ion Batteries.

Redox-active organic compounds gather significant attention for their potential application as electrodes in alkali ion batteries, owing to the structural versatility, environmental friendliness, and cost-effectiveness. However, their practical applications of such compounds are impeded by insufficient active sites with limited capacity, dissolution in electrolytes, and sluggish kinetics. To address these issues, a naphthol group-containing triarylamine polymer, namely poly[6,6'-(phenylazanediyl)bis(naphthol)] (poly(DNap-OH)) is rationally designed and synthesized, via oxidative coupling polymerization.

Influence of Different Metal Types on the Bonding Strength of Concrete Using the Arc Thermal Metal Spraying Method.

Exterior finishes protect reinforced concrete buildings against environmental factors, improve their durability, and enhance their exterior design. In this study, the influence of different metal types used in arc thermal metal spraying on the adhesion between concrete and metal coatings was analyzed. Five metals with different melting points were tested, and the differences between their melting points and surface temperatures immediately after thermal spraying were measured.

Electrochemical Cloud Point Temperature from Thermoamperometry: Real-Time Analysis for Phase Transition of Thermoresponsive Polymers.

Cloud point temperature () is a thermal index used to define the phase transition of thermoresponsive polymers. In this study, we used electrochemical techniques to obtain an electrochemical cloud point temperature () that exhibits the more accurate phase transition temperature and can replace . Thermoamperometry on an ultramicroelectrode was conducted with a poly(arylene ether sulfone) (PES) as a model system to obtain a current-temperature (-) curve in real time; the of the PES was determined from the - curve.

Synthesis and CO Capture of Porous Hydrogel Particles Consisting of Hyperbranched Poly(amidoamine)s.

We successfully synthesized new macroporous hydrogel particles consisting of hyperbranched poly(amidoamine)s (HPAMAM) using the Oil-in-Water-in-Oil (O/W/O) suspension polymerization method at both the 50 mL flask scale and the 5 L reactor scale. The pore sizes and particle sizes were easily tuned by controlling the agitation speeds during the polymerization reaction. Since O/W/O suspension polymerization gives porous architecture to the microparticles, synthesized hydrogel particles having abundant amine groups inside polymers exhibited a high CO absorption capacity (104 mg/g) and a fast absorption rate in a packed-column test.

Soluble Poly(amide-imide)s from Diamide-Diamine Monomer with Trifluoromethyl Groups.

A series of soluble aromatic poly(amide-imide)s (PAIs) was prepared from a new diamide-diamine monomer having biphenyl units with two CF groups. The diamide-diamine monomer was polymerized with 2,2'-bis(trifluoromethyl)benzidine and pyromelltic dianhydride through an imidization reaction to prepare PAIs with a controlled imide/amide bond ratio in the main chains. While the PAIs with the highest imide bond content showed a limited solubility, other PAIs were soluble in polar organic solvents and can be solution-cast into flexible freestanding films.

Highly Transparent Aromatic Polyamides from Unsymmetrical Diamine with Trifluoromethyl Groups.

Soluble and transparent wholly aromatic polyamides (PAs) were synthesized from an unsymmetrical diamine monomer having trifluoromethyl (CF) groups, 4-(4'-aminophenoxy)-3,5-bis(trifluoromethyl)aniline. The monomer was polymerized with several dicarboxylic acid monomers via the Yamazaki-Higashi polycondensation method. All of the synthesized polyamides have an amorphous morphology, and they are soluble in many polar organic solvents at room temperature.

Synthesis of Arylene Ether-Type Hyperbranched Poly(triphenylamine) for Lithium Battery Cathodes.

We synthesized a new poly(triphenylamine), having a hyperbranched structure, and employed it in lithium-ion batteries as an organic cathode material. Two types of monomers were prepared with hydroxyl groups and nitro leaving groups, activated by a trifluoromethyl substituent, and then polymerized via the nucleophilic aromatic substitution reaction. The reactivity of the monomers differed depending on the number of hydroxyl groups and the AB type monomer with one hydroxyl group successfully produced poly(triphenylamine).

Poly (Amidehydrazide) Hydrogel Particles for Removal of Cu and Cd Ions from Water.

Poly(amidoamine)s (PAMAM) are very effective in the removal of heavy metal ions from water due to their abundant amine and amide functional groups, which have a high binding ability to heavy metal ions. We synthesized a new class of hyperbranched poly(amidehydrazide) (PAMH) hydrogel particles from dihydrazides and N,N'-methylenebisacrylamide (MBA) monomer by using the A2 + B4 polycondensation reaction in an inverse suspension polymerization process. In Cd and Cu ion sorption tests, the synthesized dihydrazide-based PAMH hydrogel particles exhibited sorption capacities of 85 mg/g for copper and 47 mg/g for cadmium.

Well-Defined Dual Light- and Thermo-Responsive Rod-Coil Block Copolymers Containing an Azobenzene, MEOMA and OEGMA.

Here we report the dual light- and thermo-responsive behavior of well-defined rod-coil block copolymers composed of an azobenzene unit, 2-(2-methoxyethoxy)ethyl methacrylate (MEOMA) and oligo(ethylene glycol) methacrylate (OEGMA). Azobenzene-containing rigid rod blocks prepared by chain growth condensation polymerization of the azobenzene containing monomer were used as a macroinitiator of atom transfer radical polymerization (ATRP) after attaching an α-bromoisobutyryl group as an end group. Synthesis of well-defined rod-coil block copolymers with different coil block lengths was achieved by copolymerization of MEOMA and OEGMA monomers.

Homochiral Supramolecular Thin Film from Self-Assembly of Achiral Triarylamine Molecules by Circularly Polarized Light.

Here, we report the formation of homochiral supramolecular thin film from achiral molecules, by using circularly polarized light (CPL) only as a chiral source, on the condition that irradiation of CPL does not induce a photochemical change of the achiral molecules. Thin films of self-assembled structures consisting of chiral supramolecular fibrils was obtained from the triarylamine derivatives through evaporation of the self-assembled triarylamine solution. The homochiral supramolecular helices with the desired handedness was achieved by irradiation of circularly polarized visible light during the self-assembly process, and the chiral stability of supramolecular self-assembled product was achieved by photopolymerization of the diacetylene moieties at side chains of the building blocks, with irradiation of circularly polarized ultraviolet light.

Copper Ions Removal from Water using AB Type Hyperbranched Poly(amidoamine) Hydrogel Particles.

Micrometer-sized hyperbranched poly(amidoamine) (hPAMAM) particles are prepared with a simple AB type Aza-Michael addition reaction between aminoethylpiperazine (AEP) and methylenebisacrylamide (MBA) in an inverse suspension polymerization condition. The synthesized particles exhibited surprisingly high Cu sorption capacity (0.223g/g) for a solid-type absorbent.

Poly(amide-imide) materials for transparent and flexible displays.

The key component currently missing for the next generation of transparent and flexible displays is a high-performance polymer material that is flexible, while showing optical and thermal properties of glass. It must be transparent to visible light and show a low coefficient of thermal expansion (CTE). While specialty plastics such as aromatic polyimides are promising, reducing their CTE and improving transparency simultaneously proved challenging, with increasing coloration the main problem to be resolved.

Highly Efficient Visible Blue-Emitting Black Phosphorus Quantum Dot: Mussel-Inspired Surface Functionalization for Bioapplications.

The preparation of blue-emitting black phosphorus quantum dots (BPQDs) is based on the liquid-phase exfoliation of bulk BP. We report the synthesis of soluble BPQDs showing a strong visible blue-light emission. Highly fluorescent (photoluminescence quantum yield of ≈5% with the maximum emission (λ) at ≈437 nm) and dispersible BPQDs in various organic solvents are first prepared by simple ultrasonication of BP crystals in chloroform in the ambient atmosphere.

Observing Phase Transition of a Temperature-Responsive Polymer Using Electrochemical Collisions on an Ultramicroelectrode.

Herein, a study on a new lower critical solution temperature (LCST) polymer in an organic solvent by an electrochemical technique has been reported. The phase-transition behavior of poly(arylene ether sulfone) (PAES) was examined on 1,2-dimethoxyethane (DME). At a temperature above the LCST point, polymer molecules aggregated to create polymer droplets.

Micro-hydrogel Particles Consisting of Hyperbranched Polyamidoamine for the Removal of Heavy Metal Ions from Water.

A series of micro-hydrogel particles consisting of hyperbranched polyamidoamine (HPAMAM) without any supporting core materials was synthesized via the inverse suspension condensation polymerization of A and B monomers, N,N'-methylenebisacrylamide (MBA) and ethylenediamine (EDA). The particles were found to be highly effective when used to remove heavy metal ions, such as cadmium, copper, lead, nickel, zinc, and cobalt, from water, and they could be separated from the water by a simple filtration process. The results of this study demonstrate that crosslinked HPAMAM particles, which can be prepared by a simple and environmentally friendly process, are an attractive absorbent for water purification.

Remarkably enhanced adhesion of coherently aligned catechol-terminated molecules on ultraclean ultraflat gold nanoplates.

We report the characterization and formation of catechol-terminated molecules immobilized on gold nanoplates (Au NPLs) using N-(3,4-dihydroxyphenethyl)-2-mercaptoacetamide (Cat-EAA-SH). Single-crystalline Au NPLs, synthesized using a one-step chemical vapor transport method, have ultraclean and ultraflat surfaces that make Cat-EAA-SH molecules aligned into a well-ordered network of a large-scale. Topographic study of the catechol-terminated molecules on Au NPLs using atomic force microscopy showed more orderly orientation and higher density, leading to significantly higher adhesion as observed from local force-distance curves than those on other Au surfaces.

Production of quasi-2D graphene nanosheets through the solvent exfoliation of pitch-based carbon fiber.

Stable dispersion of quasi-2D graphene sheets with a concentration up to 1.27 mg mL(-1) was prepared by sonication-assisted solvent exfoliation of pitch-based carbon fiber in N-methyl pyrrolidone with the mass yield of 2.32%.

Induction and control of supramolecular chirality by light in self-assembled helical nanostructures.

Evolution of supramolecular chirality from self-assembly of achiral compounds and control over its handedness is closely related to the evolution of life and development of supramolecular materials with desired handedness. Here we report a system where the entire process of induction, control and locking of supramolecular chirality can be manipulated by light. Combination of triphenylamine and diacetylene moieties in the molecular structure allows photoinduced self-assembly of the molecule into helical aggregates in a chlorinated solvent by visible light and covalent fixation of the aggregate via photopolymerization by ultraviolet light, respectively.

Uncatalyzed synthesis and characterization of a water-soluble polyacetylene: poly[2-ethynyl-N-(propylsulfonate)pyridinium betaine].

A new ionic conjugated polymer was prepared by the activated polymerization of 2-ethynylpyridine with the ring-opening of 1,3-propanesultone without any additional initiator or catalyst. This polymer was characterized by various instrumental methods to have conjugated polymer backbone system with pendant N-propylsulfonate functional groups. The photoluminescence spectrum of polymer showed that the PL peak is located at 552 nm corresponding to the photon energy of 2.

Dual-mode fluorescence switching induced by self-assembly of well-defined poly(arylene ether sulfone)s containing pyrene and amide moieties.

A new class of fluorescent organogelators, pyrene-containing poly(arylene ether sulfone)s, showed two fluorescence switching modes in different gelation solvents. The THF gel exhibited excimer emission due to dimerization of the pyrene groups. In contrast, excimer emission was quenched after gelation in MC because of stacking among the pyrene groups.

Self-assembly driven by an aromatic primary amide motif.

Primary amides are unique supramolecular synthons possessing two hydrogen donors and two hydrogen acceptors. By interacting in a complementary fashion, primary amides reliably generate two-dimensional hydrogen bonded networks that differ from conventional hydrogen bonded structures such as carboxylic acid dimers or one-dimensional secondary amide chains. This feature permits the design of sophisticated supramolecular assemblies based on primary amides (especially aromatic amides).

Photoinduced reversible transmittance modulation of rod-coil type diblock copolymers containing azobenzene in the main chain.

Photoinduced reversible transmittance modulation was achieved with the self-assembled block copolymer micelles. A large conformational change of the well-defined rod-coil diblock copolymers containing azobenzene and ether groups in the main chain of the rod block induced a remarkable macroscopic change which can be observed with the naked eye.

Coordination power adjustment of surface-regulating polymers for shaping gold polyhedral nanocrystals.

PVP (poly(vinyl pyrrolidone)) is a common polymer that behaves as a surface-regulating agent that shapes metal nanocrystals in the polyol process. We have used different polymers containing tertiary amide groups, namely PVCL (poly(vinyl caprolactam)) and PDMAm (poly(N,N-dimethyl acrylamide)), for the synthesis of gold polyhedrons, including octahedrons, cuboctahedrons, cubes, and higher polygons, under the present polyol reaction conditions. The basicity and surface coordination power of the polymers are in the order of PVCL, PVP, and PDMAm.