Journal of Polymer Science Part A: Polymer Chemistry

Brønsted superacids generated by the photolysis of diaryliodonium salts can be trapped by complexing with crown ethers, as presented by James V. Crivello and Michael F. Aldersley on page 801. The figure shows a Spartan '10 molecular model of the cation of the hydronium hexafluoroantimonate-18-crown-6 ether supramolecular complex that was isolated as a crystalline solid.

Novel diblock copolymers consisting of a multibranched polymethacrylate segment with densely grafted poly[2-(2-methoxyethoxy)ethyl vinyl ether] pendants and a poly (N-isopropylacrylamide) segment are synthesized by a combination of living cationic polymerization and RAFT polymerization, as presented on page 786 by Masahiko Minoda, Tatsuya Shimizu, Sadao Miki, and Jin Motoyanagi. The obtained diblock copolymers possess well-controlled architectures. The aqueous solutions of the diblock copolymers exhibit two-stage thermoresponsive properties denoted by the appearance of two cloud points upon heating, indicating that the densely grafted poly[2-(2-methoxyethoxy) ethyl vinyl ether] pendants and the poly(N-isopropylacrylamide) segments independently respond to temperature.

This review describes the synthesis and photovoltaic performance of donor–acceptor (D–A) semiconducting polymers that have been reported during the last decade. 9,9-Dialkyl-2,7-fluorene, 2,7-carbazole, cyclopenta[2,1-b:3,4-b′]dithiophene, dithieno[3,2-b:2′,3′-d]silole, dithieno[3,2-b:2′,3′-d]pyrrole, benzo[1,2-b:4,5-b′]dithiophene, benzo[1,2-b:4,5-b′]difuran building blocks, and their D–A copolymers are described in this review.

Two poly(amidoamine) crosslinked resins whose repeating units are mimics of L-lysine (LYMA) and of EDTA (LMT85) prove capable of quantitatively and reversibly sorbing manganese ions (Mn²⁺). Halving times are on the order of 1 min or less, and Mn²⁺ can be abated to the ppb level.

A range of well-defined block copolymers were synthesized using 4-cyano-4-(dodecylsulfanylthiocarbonyl)sulfanylpentanol as a dual initiator for reversible addition-fragmentation chain transfer polymerization and ring-opening polymerization in a one-step process. Styrene, (meth)acrylate, and acrylamide monomers were polymerized in a controlled manner for one block composed of vinyl monomers, and δ-valerolactone, ε-caprolactone, trimethylene carbonate, and L-lactide were used for the other block composed of cyclic monomers.

Hollow spheres of aromatic polyamide with 3–4 μm diameters are obtained by the reaction-induced phase separation during polymerization. The droplets are initially generated via liquid–liquid phase separation and then a rigid cross-linked network structure forms the rigid skin layer on the surface of the droplets. The solidification of the droplets occurs while maintaining the morphology to form the hollow spheres. The hollow spheres exhibit outstanding thermal stability.

Diblock copolymers consisting of a multibranched polymethacrylate segment with densely grafted poly[2-(2-methoxyethoxy)ethyl vinyl ether] pendants and a poly(N-isopropylacrylamide) segment were synthesized by a combination of living cationic polymerization and RAFT polymerization. The obtained diblock copolymers possessed relatively narrow molecular weight distributions and controlled molecular weights. The aqueous solutions of the diblock copolymers exhibited two-stage thermoresponsive properties denoted by the appearance of two cloud points, upon heating, indicating that the densely grafted poly[2-(2-methoxyethoxy)ethyl vinyl ether] pendants and thepoly(N-isopropylacrylamide) segments independently responded to temperature.

Self-assembly of cholesteryl N-(2-anthryl) carbamate (CAC) results in the formation of helical structures. The results of temperature-dependent ¹H NMR spectroscopy indicate that hydrogen bond-assisted π–π interaction maintains the growth of the axis of the self-assembled construction, and the three-dimensional effect from the cholesteryl group induces the rotational structure. In the gel state, significant enhanced fluorescence strength is observed because of the aggregation-induced enhanced emission of CAC molecules.

Crystalline 1:1 supramolecular complexes of diaryliodonium salts 18-crown-6 ether and its analogs are photosensitive and were used as photoinitiators to carry out the cationic polymerizations of a number of mono- and difunctional monomers. The crown ether that is released on photolysis markedly influences the kinetics of the subsequent cationic polymerization of the monomer by complexing with the photogenerated acid.

A series of novel, solvent processable, fluorene-based conjugated copolymers are synthesized and characterized and their thermal, optical, electrochemical and sensory properties are investigated.

The concentration of the (1,3-phenylene)bis(3-methyl-1-phenyl pentylidene)dilithium initiator (DLI) in the polymerization of butadiene (Bd) in benzene, in the presence of s-BuOLi at room temperature, is very important for the modality of the resulting polybutadiene (PBd). Keeping the s-BuOLi/C-Li ratio close to unity, at relatively high DLI concentrations (C > 7×10⁻⁴ M) monomodal high 1,4-PBds with polydispersity index less than 1.07 were obtained, whereas bimodal ones were obtained at lower concentrations (C<6×10⁻⁴ M).This is due to the inevitable presence of protic impurities which are more pronounced in the case of lower DLI concentrations.

A series of Y-type polymers containing different aromatic rings as donors and a dicyanomethylene group as acceptor are synthesized by Knoevenagel condensation. The polymers have reasonably high T_g up to 212 °C. The atomic force microscopic spectra have given clear presentation of noncentrosymmetrical arrangement after poling. The second-harmonic generation intensity was found to remain stable up to about 165 °C.

A series of new vanadium complexes bearing tridentate phenoxy-phosphine [O,P(O),O] ligands have been synthesized, characterized, and investigated as the catalyst precursors for ethylene (co)polymerization.

A novel approach to the preparation of multifunctional amphiphilic silicone architectures is reported. The synthetic strategy relies on successive, thermal (metal free) cycloadditions of azides to activated alkynes (Click chemistry), which provides access to novel polymeric silicone surfactants in high yield and without generating any byproducts.

Simultaneously, dual end-functionalization of PEG via the Passerini three-component reaction and subsequent LRP and click chemistry for the synthesis of three types of ABC miktoarm terpolymers were demonstrated. With the unique characteristics of the Passerini reaction, that is, atom efficiency, ambient reaction conditions, and three components, this reaction may find wide applications in constructing more complex macromolecular architectures.

The terpolymerization of CO₂, styrene oxide and epoxide, bearing an electron-donating group has been achieved with the use of cobalt-based complexes as catalyst at mild conditions. A random distribution of the two kinds of carbonate units is present in the CO₂/styrene oxide/propylene oxide terpolymer, whereas an alternating nature of the two different carbonate units predominantly exists in the CO₂/styrene oxide/CHO terpolymer.

Among the acrylate monomers modeled in this study, phenyl acrylate has the highest reactivity, which is consistent with experimental findings. The transition structure of phenyl acrylate is mainly stabilized by close and strong CO…H-Φ interactions as well as by π–π stacking (parallel-displaced type interaction with distance of 5.30 Å from center to center). The aromatic groups are held together by CO…H-Φ interactions (2.166 and 2.365 Å).

Fully bio-based polyesters were synthesized by bulk polycondensation from 2,5-furandicarboxylic acid or dimethyl-2,5-furandicarboxylate and 2,3-butanediol using titanium (IV) n-butoxide, tin (IV) ethylhexanoate, or zirconium (IV) butoxide as catalyst. The chemical structure of the synthesized poly(2,3-butylene-2,5-furandicarboxylate)s was elucidated by MALDI-ToF-MS, ¹H-NMR, ¹³C-NMR, FTIR, ESI-ToF-MS, and ESI-Q-ToF-MS-MS, and their thermal properties were studied using differential scanning calorimetry and thermogravimetric analysis. Suitable functionality, molecular weight, and thermal properties can make these polyesters appropriate candidates for coating or hot-fill applications.

In this study, an equimolar mixture of oxanorbornenyl-anthracene (ONB-anthracene), oxanorbornenyl-bromide (ONB-Br), and oxanorbornenyl tosylate (ONB-OTs) was polymerized via ring opening metathesis polymerization using the first generation Grubbs' catalyst in CH₂Cl₂ at room temperature to form poly(ONB-anthracene-co-ONB-Br-co-ONB-OTs)₁₀ copolymer as a main backbone. Next, this main backbone was sequentially clicked with a furan protected maleimide-terminated poly(methyl methacrylate) (PMMA₂₅-MI), 2,2,6,6-tetramethyl-1-piperidinyloxy-terminated poly(ethylene glycol) (PEG₁₁-TEMPO), and alkyne-terminated poly(ε-caprolactone) (PCL₂₀-alkyne) via Diels-Alder, nitroxide radical coupling (NRC), and copper catalyzed azide-alkyne cycloaddition (CuAAC), respectively, to yield a poly(ONB-g-PMMA-co-ONB-g-PEG-co-ONB-g-PCL)₁₀ heterograft brush copolymer.

Two poly(3-decyl-2,2′-bithiophene) polymers have been synthesized through Stille AABB-type polycondensations, which limits the location of the alkyl side-chain to be present exclusively on every other thiophene unit. However, the relative orientation of the side-chains differ in polymers 1 and 2. The regiochemistry of these two polymers are analyzed by ¹H NMR, ¹³C NMR, and HSQC spectroscopy, and the impacts of the different structures on the polymer properties are studied with UV–vis spectroscopy, DSC, and GIXD.

Three benzobisthiazole-containing polymers are synthesized and their optical and electronic properties are reported. The polymers possess good molecular weights and high electron affinities while exhibiting efficient green fluorescence in solution and orange in film. The polymers were used as the emissive guest material in guest-host polymer light-emitting diodes with a poly(N-vinylcarbazole) host. The devices had a maximum brightness of 478 Cd/m² and a maximum luminous efficiency of 0.61 Cd/A with blue-green emission.

A series of comb-like polymers, poly{2,5-bis[(4-octadecyloxyphenyl)oxycarbonyl]-styrenes} (P-OC18s) with different molecular weights have been successfully synthesized via ATRP. The phase behaviors of the polymers have been investigated by a combination of techniques including DSC, POM, 1D WAXD, and VT-FTIR. Combined the driving force of the enthalpy and the driving force of the entropy, the phase behaviors of the polymers were found to be strongly M_n dependent. The P-OC18s with low molecular weight formed the crystal, smectic A phase, and isotropic phase, while the P-OC18s with high molecular weight exhibited the crystal, smectic A phase, reentrant isotropic phase, and columnar phase.

A new class of photo- and electrically switchable azobenzene containing side-chain bent-core liquid crystalline monomers (AZBM 1-3) and their polymers (AZBP 1-3) were prepared. All the monomers demonstrate SmCP phase and their respective polymers show smectic phase with grainy like textures. Among the three monomers, AZBM-1 & 2 exhibit antiferroelectric (AF) switching and AZBM-3 exhibits ferroelectric (F) switching behavior. On the other hand, low molecular weight AZMP-1, 2 & 3 show weak AF and F switching behavior. The polymers show UV and visible photo-switching properties and they are also thermally reversible.

New crystalline nanostructured inorganic-organic hybrid materials containing isotactic polystyrene (iPS) are prepared by means of hydrosilylation coupling of vinyl-terminated iPS with octakis(dimethylsilyloxy)silsesquioxane (Q₈M₈H). As a function of the iPS/Q₈M₈H ratio, using excess reagent, the formation of linear (iPS-Q₈M₈E₇) or star-shaped (iPS_6-8-Q₈M₈) hybrid architectures is achieved. These new iPS/POSS hybrid materials crystallize when the number average molar mass of iPS side chain exceeds 5500 g mol⁻¹ and forms spherulites with a structural dependence.

Poly(2-(2-methoxyethoxy)ethyl methacrylate) chains were grown in situ from the surface of 4-cyano-4-(dodecylsulfanylthiocarbonyl)sulfanyl pentanoic acid modified silicon via RAFT-mediated polymerization to produce polymer brushes with a grafting density as high as 0.7 chains/nm² and thermoresponsibility.

Polyisophthalamides with side chains of polyethylene oxide (PEO) were prepared by incorporating PEO sequences onto poly(5-hydroxy-isophthalamide)s. The polymers behaved as graft copolymers of polyisophthalamide (PIPA) and PEO, covering a wide range of ratios of PIPA/PEO. For high contents of PEO, the materials could absorb water in high amounts and they tended to micellize in polar solvents. Gravimetric methods and water contact angle measurements were used to quantify the hydrophilicity of the current PEO-modified polyisophthalamides.

Novel fluorinated poly(CTFE-alt-vinyl ether-bearing oligo(EO)) copolymers were prepared by radical copolymerization of CTFE with vinyl ether macromonomers bearing oligo(EO) chains of various lengths, obtained in good yield. They were characterized by ¹H, ¹⁹F, and ¹³C NMR spectroscopy, size exclusion chromatography and their thermal properties investigated (suitable stability and low T_g). Electrolytes based on these copolymers have RT ionic conductivities ranging from 4.49 × 10⁻⁷ to 1.45 × 10⁻⁶ S cm⁻¹ arising from coordination of Li⁺ by the PEO units.

A triazoloquinoxaline and 9,9-dialkylfluorene incorporated donor/acceptor-type copolymer PTQF has been synthesized and is utilized in bulk-heterojunction solar cells as donor material. Its electrochemical and photovoltaic properties revealed that the new triazoloquinoxaline unit could be a great candidate for low band-gap materials for organic photovoltaics.