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Highly conductive and stable anion exchange membranes (AEMs) are important components of high-performance anion exchange membrane fuel cells (AEMFCs). Here, we report the use of crosslinked poly(arylene ether sulfone) (PAES) AEMs containing quaternary ammonium (QA) and triazolium cations. The crosslinked PAES-triazole-hydroxide membrane (cPAES-TA-OH) had a higher ion exchange capacity (IEC) than that of the non-crosslinked membrane (PAES-TA-OH) owing to the presence of triazolium cations. The IEC values of cPAES-TA-OH and PAES-TA-OH were 1.75 and 1.31 meq/g, respectively. The IEC value affects the water uptake and swelling ratio of a membrane. The water uptake and swelling ratio of cPAES-TA-OH were higher than those of PAES-TA-OH at 30 °C and 80 °C. In addition, hydroxide conductivity and membrane stability were enhanced by crosslinking; the hydroxide conductivity of cPAES-TA-OH was 92.1 mS/cm at 80 °C under 95% RH (in contrast to 86.2 mS/cm for PAES-TA-OH), and its conductivity retention was 67% after treating with 1M NaOH at 80 °C for 24 h (in contrast to 51% for PAES-TA-OH).

Iridium complex-incorporated monodisperse particles are prepared via surfactant-free emulsion polymerization. For this process, a vinyl-substituted iridium complex (IrV) is synthesized and copolyme...

We present the facile synthetic platform for the production of amphiphilic bottlebrush block copolymers bearing pyridine pendants through combination of living anionic polymerization (LAP), ring-op...

Well-defined ambipolar block copolymers containing carbazole, oxadiazole moieties, and only one homoleptic iridium(III) complex between the carbazole and oxadiazole blocks were successfully synthesized by sequential living anionic polymerization with controlled molecular weights (Mw), a narrow molecular weight distribution (Mw/Mn < 1.15), and a high conversion yield (98–100%). The optimum conditions for the successful controlled synthesis of an oxadiazole-containing the homopolymer of poly(2-phenyl-5-(6-vinylpyridin-3-yl)-1,3,4-oxadiazole) have been established by controlling the nucleophilicity strength of the carbanion. In addition, the location and concentration of the homoleptic iridium(III) complex were controlled by linking it to 1,1-diphenylethylene, which exhibits monoaddition characteristics in the main chain of the block copolymer.

A supramolecular aggregate with molecular-level ordering, is prepared by the hydrogen-bonding self-assembly of poly(4-(4-vinylphenylpyridine)) (P4VPPy) and 1,1′-ferrocenedicarboxylic acid (FDA) in dimethyl sulfoxide (DMSO) using a solvent vapor thermal annealing process. Co-dissolving P4VPPy and FDA in DMSO leads to hydrogen bonding between the pyridine and carboxylic acid. This is confirmed by Fourier transform-infrared spectroscopy and X-ray photoelectron spectroscopy. The crystalline morphology of the resulting thin films are investigated by high-voltage electron microscopy coupled with X-ray diffraction, which reveals that hydrogen bonding assisted self-assembly of P4VPPy and FDA results in precise arrangements of both the polymer chains and FDA molecules providing a highly ordered material with a face-centered cubic crystal structure. The X-ray spectra shows crystalline peaks with d spacing in the (100) direction and supports the high-voltage electron microscopy results. Furthermore, P4VPPy also interacts with 2,6-naphthalenedicarboxylic acid (NTDA), 1,4-benzenedicarboxylic acid (BZDA) and 1,2-ethanedicarboxylic acid (EDA) separately, and these structures are compared with the ordering behavior of P4VPPy⋯FDA.

Metal-free anionic polymerization of n-hexyl isocyanate (HIC) catalyzed by phosphazene bases in THF at −98 °C under 10−6 Torr was attempted to obtain poly(n-hexyl isocyanate) (PHIC) peptide mimics with a high purity. tert-Butylimino-tris(dimethylamino)phosphorene (t-BuP1), 1-tert-butyl-2,2,4,4,4-pentakis(dimethylamino)-2λ5,4λ5-catenadi(phosphazene) (t-BuP2), and 1-tert-butyl-4,4,4-tris(dimethylamino)-2,2-bis[tris(dimethylamino)-phosphoranylidenamino]-2λ5,4λ5-catenadi(phosphazene) (t-BuP4) with the characteristic orders of basicity and bulkiness (t-BuP1 < t-BuP2 < t-BuP4) were used as catalysts to activate N-phenethyl-3-phenylpropanamide ((PhEt)2OCNH, PEPPA). Only t-BuP2 and t-BuP4 generated the initiating amidate anions paired with each phosphazenium cation, which produced PHICs with MWs higher than the theoretical ones and characteristic ranges of dispersities. A moderately low dispersity was achieved by t-BuP2. The anionic polymerization of HIC catalyzed by t-BuP2 with molar feed ratios of the monomer to the initiator ([HIC]0/[PEPPA]0) within the range 207–801 produced PHICs with high yields (96.9–98.7%) and high MWs (Mn = 44.1–174 kDa, Đ = 1.37–1.64) that were linearly controlled by the feed ratios, even though no polymers were obtained by t-BuP1, and the products whose production was catalyzed by t-BuP4 had unpredictable MWs and high dispersities (Đ = 1.82–2.20).

Self-healing polyurethane with disulfide bonds was synthesized using polycarbonate diol as a soft segment, and methylene diphenyl diisocyanate and 2-hydroxyethyl disulfide as a hard segment. Well-developed phase separation as the hard segments increased was confirmed by Fourier transform infrared spectra. The X-ray diffraction data showed that the crystallinity of the polycarbonate with a semicrystalline structure decreased as the HS increased, which affected the thermal, mechanical, and thermomechanical properties of the PU block copolymer. As the hard segments increased, the yield point on the strain-stress curve disappeared, and the mechanical properties (elongation at break and breaking stress) and the shape recovery rate of SHPU improved. The increase in the physical crosslinking between the hard segments contributed to improving shape recovery and mechanical properties. In particular, self-healing polyurethane with 30, and 35 wt% hard segments showed excellent self-healing ability at 80 C, while the self-healing ability for self-healing polyurethane with 40 wt% hard segments was decreased. The increase of the hard segment restricted the movement of the soft segment, thus the self-healing ability of SHPU with 40 wt% HS was decreased. It could be concluded that self-healing polyurethane synthesized using semicrystalline PC diol has a significant effect on shape recovery and self-healing efficiency due to the crosslinks between the hard segments.

The self-healing polyurethane films have received significant attention due to their unique shape memory behaviors and the hydrogen bonding arising from the urethane linkages. However, it is still a challenge to develop self-healing polyurethane with transparent, high impact resistance, and excellent shape recovery and mechanical properties. In particular, polycarbonate-based polyurethane shows transparency, weatherability and excellent mechanical properties. In this work, transparent self-healing polyurethane film with robust mechanical properties (breaking stress of 26 MPa and elongation at break of 630%) was synthesized by controlling the different molecular weight of the polycarbonate diol and incorporating dynamic disulfide bonds for reversibility. As a result, the self-healing polyurethane film showed an excellent self-healing ability with 98% healing efficiency and excellent shape memory ability with a recovery efficiency of ˃92%. In addition, we have identified a potential application for the self-healing flexible substrate in flexible electronics because of their stable electrical resistance even upon mechanical deformation.

Well-controlled polystyrene-polymethacrylate bottlebrush block copolymers (BBCPs) of ultrahigh molecular weight using ω-end-norbornyl polystyrene as the macromonomer for the first block were synthesized by combining living anionic polymerization (LAP) and ring-opening metathesis polymerization (ROMP). The ω-end-norbornyl polystyrene (NB-PSt), poly(tert-butyl methacrylate) (NB-PtBMA), poly(methyl methacrylate) (NB-PMMA), and poly(benzyl methacrylate) (NB-PBzMA) macromonomers (MMs) were synthesized by the LAP. The ROMP of the MMs led to poly(NB-g-St) (molecular weight, Mn = 1515 kDa, and dispersity, Ð = 1.12), poly(NB-g-tBMA) (Mn = 1470 kDa, Ð = 1.49), poly(NB-g-MMA) (Mn = 1128 kDa, Ð = 1.42), and poly(NB-g-BzMA) (Mn = 941 kDa, Ð = 1.16) bottlebrush homopolymers at degree of polymerization (DP) of 500. Synthesis of the BBCP, P(NB-g-St)-b-P(NB-g-tBMA) was well-controlled with high molecular weight and a low dispersity (Mn = 3002 kDa, Ð = 1.17) with a total DP of 976. The self-assembly of the resulting BBCP films revealed periodic lamellar morphologies with characteristic photonic crystal properties.

12-(cis-5-Norbornene-exo-2,3-dicarboximido)dodecanoate pentafluorophenyl ester (exo-NBC12-PFP) was used as a norbornene-substituted end-capping terminator of living anionic polymers. Polystyrene wi...

A simple strategy was explored to systematically control the phase transition of an amphiphilic bottlebrush block copolymer (AmBBCP), poly[(norbornene-graft-styrene)-block-(norbornene-graft-hydroxy...

Furfuryl isocyanate (FIC), allyl isocyanate (AIC), and n-hexyl isocyanate (HIC) that have different β-carbon substituents were employed as monomers in living anionic homo- and copolymerization. The rate constants of the self- and cross-propagation reactions were determined, and their comparison showed the electrophilicity order of isocyanate as FIC > AIC > HIC. The kinetic analysis revealed that the anionic copolymerization of FIC:HIC, AIC:HIC, and FIC:AIC generated three different sequence-controlled polyisocyanate copolymers, poly(furfuryl isocyanate-block-n-hexyl isocyanate) (P(FIC-b-HIC)), poly(allyl isocyanate-tapered block-n-hexyl isocyanate) (P(AIC-tb-HIC)), and poly(furfuryl isocyanate-gradient-allyl isocyanate) (P(FIC-grad-HIC)), respectively. The homogeneous sequential anionic copolymerization of the binary isocyanate mixtures generated the polyisocyanate copolymers having repeated monomer sequences. A series connection of P(FIC-b-HIC), P(AIC-tb-HIC), and P(FIC-grad-HIC) segments in the copolyme...

Self‐emulsion polymerization (SEP), a green route developed by us for the polymerization of amphiphilic monomers, does not require any emulsifier or an organic solvent except that the water‐soluble initiators such as 2,2′‐azobis[2‐(2‐imidazolin‐2‐yl)propane]dihydrochloride (VA‐044) and potassium persulfate (KPS) are only used. We report here the polymer nanoscaffolds from a number of amphiphilic monomers, which can be used for in situ encapsulation of a variety of nanoparticles. As a demonstration of the efficacy of these nanoscaffolds, the synthesis of a biocompatible hybrid nanoparticle (nanohybrid), prepared by encapsulating Fe₃O₄ magnetic nanoparticle (Fe₃O₄ MNPs) in poly(2‐hydroxyethyl methacrylate) in water, for MRI application is presented. The nanohybrid prepared following the SEP in the form of an emulsion does not involve the use of any stabilizing agent, crosslinker, polymeric emulsifier, or surfactant. This water‐soluble, spherical, and stable nanohybrid containing Fe₃O₄ MNPs of average size 10 ± 2 nm has a zeta potential value of −41.89 mV under physiological conditions. Magnetic measurement confirmed that the nanohybrid shows typical magnetic behavior having a saturation magnetization (Ms) value of 32.3 emu/g and a transverse relaxivity (r2) value of 29.97 mM⁻¹ s⁻¹, which signifies that it can be used as a T2 contrast agent in MRI. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019

A rod-rod diblock copolymer (diBCP), poly(3-hexylthiophene)-block-poly(furfuryl isocyanate) (P3HT-b-PFIC), was synthesized through the anionic polymerization with an oxyanionic macroinitiator of P3HT. The properties of the diBCP (molecular weight, dispersity, composition, thermal stability, UV-visible absorption, and thin film morphology) were determined by various analytical methods. P3HT-b-PFIC was blended with C60 in a toluene solution to prepare a thin film of binary electron donor/acceptor system. Such blending enabled partial conjugation of the two components by the Diels-Alder reaction between furan and C60 at 60 °C for 3 h; the mixture was then spin-cast as a thin film, and annealed at 250 °C for 24 h. Tapping-mode atomic force microscopy (AFM) revealed that P3HT and C60 domains had nanoscale interfaces without a large phase segregation. This result indicated that the microphase separation of C60-functionalized P3HT-b-PFIC preserved even at high temperature provided free C60 molecules with channels to diffuse on the sides of P3HT domain, thus preventing the macroscopic crystallization of free C60 through the interfacial stabilization.

We compared the interfacial activity of two classes of POSS-bottlebrush block copolymers (POSSBBCPs) in the breath-figure (BF) self-assembly. Poly[3-(5-norbornene-exo-2,3-dicarboximido)propyl-heptaisobutyl POSS]-block-poly(exo-5-norbornene-2-carbonylate-graft-benzyl methacrylate) (P1-b-P(NB-g-BzMA)) and poly[3-(2-(5-norbornene-exo-2,3-dicarboximido)ethylamino)propyl-heptaisobutyl POSS]-block-poly(exo-5-norbornene-2-carbonylate-graft-benzyl methacrylate) (P2-b-P(NB-g-BzMA)), which contain nonfunctionalized and secondary-amino-functionalized POSS-based blocks, respectively, were prepared by sequential ring-opening metathesis polymerization of norbornenyl monomers (P1-b-P(NB-g-BzMA) with fP1 = 50 wt % (1–50): Mn = 213 kDa, Đ = 1.12; P2-b-P(NB-g-BzMA)s with fP2 = 5/11/20/50 wt % (2–5/11/20/50): Mn = 2464/1043/581/268 kDa, Đ = 1.46/1.26/1.24/1.20). Of 1–50 and 2–50, only 2–50 afforded the three-dimensional porous films with unimodal pore size distributions. At high wet thickness, the efficient encapsulation of...

Molecular-level ordering provides a powerful approach to enhancing the properties of materials. However, the precise arrangement of molecules in a bulk material is a considerable challenge. To overcome such limitations, hydrogen bonding-directed self-assembly has drawn a lot of attention due to its facile nature in controlling molecular-level order. In this study, we report ordering of the magnetic Fe centers achieved through hydrogen bonding between poly(4-vinylpyridine) (P4VP, MW 60 kDa) and 1,1′-ferrocenedicarboxylic acid (FDA). Co-dissolving P4VP and FDA in dry methanol leads to P4VP–FDA showing an unprecedented degree of order for both FDA and the polymer chain. Such an event of mutual assistance between a dicarboxylic acid and a high molecular weight polymer chain in building the ordered supramolecular architecture is rare. FDA is uniformly distributed in an ordered polymer matrix, with each Fe center in P4VP–FDA linked at the molecular-level through polymeric bridges in a face-centered cubic struct...

We report the propagation-inspired initiation of sodium N-phenethyl-3-phenylpropanamide (NaPEPPA), an aliphatic sodium amidate, for the living anionic homo- and copolymerization of isocyanates. This initiator was compared with sodium benzanilide (NaBA), an aromatic sodium amidate, in the living anionic homopolymerization of n-hexyl isocyanate (HIC). Only NaPEPPA attained the initiation efficiencies close to unity at the early stage of propagation. The homopolymerization with [HIC]0/[NaPEPPA]0 = 38.9/85.1/203 led to poly(n-hexyl isocyanate)s (PHICs) with predictable MWs and low dispersities (Mn,theo = 5.12/10.7/24.7 kDa; Mn = 5.22/11.1/27.4 kDa; Đ = 1.11/1.10/1.06). NaPEPPA was also used to initiate the living anionic copolymerization of HIC and furfuryl isocyanate (FIC). As a result, poly(furfuryl isocyanate-block-n-hexyl isocyanate) (P(FIC-b-HIC)) was afforded by the blocky monomer sequence distribution. Based on the copolymerization kinetics, a series of polyisocyanate-based multiblock copolymers, P(FIC...

Anionic polymerization of n-hexyl isocyanate (HIC) in THF at −98 °C under 10–6 Torr for the kinetic study was performed by the initiation of sodium diphenylmethane (NaDPM) in either the absence or presence of sodium tetraphenylborate (NaBPh4; [NaBPh4]0/[NaDPM]0 = 0 or 5). The common-ion effect of NaBPh4 to suppress the formation of unstable free amidate anions led to termination-free propagation by amidate ion pairs. In [HIC]0/[NaDPM]0 = 50.8/101/201, the initiation of NaDPM early reached ∼100% efficiencies during propagation, which led to the yield of poly(n-hexyl isocyanate)s (PHICs) with predictable molecular weights (Mn,theo = 6.50/12.7/24.7 kDa; Mn = 6.50/12.7/26.1 kDa) and low dispersities (Đ = 1.06/1.07/1.15). Within the conditions, the rate of propagation accorded with a first-order dependence on [NaDPM]0, indicating that the propagating amidate ion pairs are intrinsically unimeric (nonassociated). Kinetics of anionic copolymerization of HIC and allyl isocyanate (AIC) exhibited a monomer distribut...

Hard–soft–hard triblock copolymers based on poly(ethylene oxide) (PEO), poly(2-naphthyl glycidyl ether)-block-poly[2-(2-(2-methoxyethoxy)ethoxy)ethyl glycidyl ether]-block-poly(2-naphthyl glycidyl ether)s (PNG-PTG-PNGs), were synthesized by sequential ring-opening polymerization of 2-(2-(2-methoxyethoxy)ethoxy)ethyl glycidyl ether and 2-naphthyl glycidyl ether using a bidirectional initiator catalyzed by a phosphazene base. Four PNG-PTG-PNGs had different block compositions (fwt,PNG = 9.2–28.6 wt %), controlled molecular weights (Mn = 23.9–30.9 kDa), and narrow dispersities (Đ = 1.11–1.14). Most of the PNG-PTG-PNG electrolytes had much higher Li+ conductivities than that of a PEO electrolyte (6.54 × 10–7 S cm–1) at room temperature. Eespecially, the Li+ conductivity of PNG18-PTG107-PNG18 electrolyte (9.5 × 10–5 S cm–1 for fwt,PNG = 28.6 wt %) was comparable to one of a PTG electrolyte (1.11 × 10–4 S cm–1). The Li+ conductivities of PNG-PTG-PNG electrolytes were closely correlated to efficient Li+ transpor...

To achieve molecular packing of protic-functionalized helical polymers in aqueous solution, we synthesized an amphiphilic helix–coil–helix triblock copolymer (triBCP) composed of polystyrene and dihydroxyl-functionalized polyisocyanates. Poly(3-(glycerylthio)propyl isocyanate)-block-polystyrene-block-poly(3-(glycerylthio)propyl isocyanate), P3GPIC-b-PSt-b-P3GPIC, was synthesized by postpolymerization modification. The bidirectional anionic block copolymerization of styrene (St) and allyl isocyanate (AIC) yielded triBCPs, poly(allyl isocyanate)-block-polystyrene-block-poly(allyl isocyanate)s (PAIC-b-PSt-b-PAICs), with well-controlled molecular weights (Mn = 5.60–99.9 kDa) and narrow dispersities (Đ = 1.14–1.18). Of them, one with the lowest MW (Mn = 5.60 kDa, Đ = 1.14), which was highly organic-soluble, was utilized in the thiol–ene click reaction between allyl group and 1-thioglycerol, producing P3GPIC-b-PSt-b-P3GPIC. The amphiphilic P3GPIC-b-PSt-b-P3GPIC self-aggregated to form spherical vesicles with an...

Cube-like polyhedral oligomeric silsesquioxane (POSS) is a promising candidate for isotropically bulky pendants to expand the dimensional limit of polymer main chains. This paper presents molecular and kinetic insights into the controlled synthesis of rod-like POSS-containing polynorbornenes. Ring-opening metathesis polymerization (ROMP) was performed on three norbornene-substituted POSS monomers with different spacers. For monomers possessing non- and amide functionalities at the spacers, ROMP at the maximum concentration ([M]0 = 0.4 M) led to 100% conversion, predictable molecular weights (Mn ≤ 1236 kDa) and low dispersities (Đ ≤ 1.20) in homopolymers. Scaling analysis for POSS-containing polynorbornenes revealed an unusual finding, namely, that the periodic clustering of POSS pendants favored by long flexible spacers (16-atom chains) enhanced the rigidity of polynorbornene main chains, leading to their rod-like conformation. Kinetically optimized ROMP allowed the subsequent addition of a macromonomer to create POSS-bottlebrush copolymers (POSSBBCPs). These POSSBBCPs self-assembled into thin films to form ordered nanostructures with diverse morphologies and periodicities greater than 100 nm.

Functionalized polymer filter (FPF) was fabricated using a synthesized terpolymer containing a quaternary ammonium moiety via electrospinning method to enhance the durability of air filters. Removal efficiency and durability of FPF were exhibited compared with those of polystyrene (PS) filter and a commercial electret filter. FPF showed the best performance than others, and the removal efficiencies were 89.5, 98.6, and 99.8% when the sodium chloride aerosol were sized in 100, 200, and 300 nm, respectively. In addition, FPF had almost no decrease in the removal efficiency after the treatment by isopropyl alcohol (IPA). On the other hand, the IPA-treated PS and electret filter showed the rapid decrease around 20–40% for the sodium chloride aerosol. The performance of FPF was also kept even after the water treatment. Furthermore, FPF also showed good antibacterial activity, a desirable characteristic for using the air filter without infections.

Soft contact lenses made with poly(2-hydroxyethyl methacrylate) (pHEMA) hydrogels modified with various comonomers such as N-vinyl pyrrolidone, methacrylic acid, glycidyl methacrylate, and glycerol monomethacrylate were prepared to investigate the effect of adding the comonomer on the water content, surface wettability, and tensile modulus. These polymers were synthesized by the free radical polymerization of 2-hydroxyethyl methacrylate (HEMA) with the comonomers in the presence of divinyl benzene used as the crosslinker and azobisisobutyronitrile as the initiator. The chemical structure and transmittance of the hydrogels were analyzed by FTIR and UV/Vis spectrophotometers. The surface wettability and tensile modulus were also studied by measuring the contact angle and tensile modulus with a universal testing machine (UTM). Regarding the properties of water in the hydrogels, the ratio between free to bound water was investigated using differential scanning calorimetry (DSC). As the concentration of crosslinker in the hydrogels increases, the tensile strength also increases, whereas the internal water content and contact angle decrease. The effect of the comonomer composition of the hydrogels was also investigated to optimize the various properties of these comonomers for soft contact lenses.

Access to protein-inspired polyisocyanates with high molecular weights (MWs) from anionic polymerization of isocyanates is challenging as it requires exceptional livingness. For this purpose, a dimerically self-associated sodium diphenylamide (NaDPA) was introduced as a robust chain-end-protective initiator in the anionic polymerization of n-hexyl isocyanate (HIC) in the absence or presence of sodium tetraphenylborate (NaBPh4) additive. At [NaDPA]0/[NaBPh4]0 = 5, unusual one-half initiation efficiency and one-half order of reaction kinetics were observed. Accordingly, initiator-transfer anionic polymerization (ITAP), a mechanism driven by the dimer of NaDPA ((NaDPA)2) in a dual role is proposed, in which one unimer initiates the polymerization and the other reversibly deactivates the propagating chain end through its repetitive cycles of 1:1 cross-association/dissociation. Living ITAP by NaDPA with NaBPh4 was proven by X-ray crystallography, density functional theory calculation, and quantitative yield of...

Anionic polymerization is one of the most powerful techniques for preparation of well-defined polymers. However, this well-known and widely employed polymerization technique encounters major limitations for the polymerization of functional monomers containing heteroatoms. This work presents the anionic polymerization of 2-phenyl-5-(6-vinylpyridin-3-yl)-1,3,4-oxadiazole (VPyOzP), a heteroatom monomer that contains both oxadiazole and pyridine substituents within the same pendant group, using various initiating systems based on diphenylmethyl potassium (DPM-K) and triphenylmethyl potassium (TPM-K). Remarkably, well-defined poly(2-phenyl-5-(6-vinylpyridin-3-yl)-1,3,4-oxadiazole) (PVPyOzP) polymers having predicted molecular weights (MW) ranging from 2200 to 21 100 g/mol and polydispersity indices (PDI) ranging from 1.11 to 1.15 were prepared with TPM-K, without any additional additives, at −78 °C. The effect of temperature on the polymerization of PVPyOzP was also studied at −78, −45, 0, and 25 °C, and it wa...

Quaternized polymer electrolytes (QPXs) with various lengths of side chains terminating in quaternary ammonium groups are synthesized, with the aim of enhancing anion conductivity. When chain lengths are equal, the crosslinked membranes have better alkaline stabilities than non-crosslinked membranes. cQPH, which has a hexyl acyl chain and a crosslinked structure shows the best anion conductivity (105 mS/cm at 80 °C) owing to a good phase separation. In addition, it has superior alkaline stability, retaining up to 88% of its conductivity after immersion in 1 M NaOH at 80 °C for 16 days. Moreover, QPXs and cQPXs show enough thermal stability over 200 °C to operate in alkaline fuel cell systems. The dimensional stabilities of the membranes are measured, showing that water is absorbed while the strength is maintained. These results imply that cQPXs can be promising materials for use in alkaline fuel cells.

Rodlike “POSS–bottlebrush block copolymers” (POSSBBCPs) containing crystalline polyhedral oligomeric silsesquioxane (POSS) pendants in A block and amorphous polymeric grafts in B block were utilized to create one-dimensional (1D) photonic crystals (PCs). 3-(12-(cis-5-Norbornene-exo-2,3-dicarboximido)dodecanoylamino)propylheptaisobutyl POSS (NB-A16-POSS, MA) and exo-5-norbornene-2-carbonyl-end poly(benzyl methacrylate) (NBPBzMA, MB) were employed in sequential ring-opening metathesis polymerization to afford poly[3-(12-(cis-5-norbornene-exo-2,3-dicarboximido)dodecanoylamino)propylheptaisobutyl POSS]-block-poly(exo-5-norbornene-2-carbonylate-graft-benzyl methacrylate)s, P(NB-A16-POSS)-b-P(NB-g-BzMA)s, with well-modulated block compositions (fA = 34, 50, and 67 wt %) and overall degrees of polymerization (DP = 323–939). The P(NB-A16-POSS)-b-P(NB-g-BzMA)s hierarchically self-assembled to form highly ordered 1D PC films with periodic lamellar arrays that can reflect visible light with particular wavelengths. Their reflectance bandwidths, reflectivities, and ranges of peak reflectance wavelnegth (λ_(peak)) were largely dependent on the block composition. The 1D PC films based on lamellar P(NB-A16-POSS)-b-P(NB-g-BzMA)s demonstrated the capability of formaulation of λ_(peak) as linear functions of initial polymerization parameter ([M]_0/[I]_0).

A comprehensive examination of the synthesis of single-chain nanoparticles (SCNPs) from statistical copolymers of n-butyl methacrylate (BMA) and 3-butenyl methacrylate (3BMA), i.e., P(BMA-co-3BMA)s, via the intramolecular olefin metathesis reaction under high dilution conditions is described. The olefin metathesis reaction of P(BMA-co-3BMA) using Grubbs’ 2nd generation catalyst in CH2Cl2 efficiently gave the corresponding SCNPs under mild conditions. We achieved the size-controlled synthesis of the SCNPs by adjusting the following factors: (1) the olefin content in the precursor, (2) the molecular weight of the precursor, and (3) the solvent quality of the reaction medium. The hydrodynamic radius and the intrinsic viscosity of the resultant SCNPs were investigated by DLS and viscometric measurements, respectively, which provided further evidence of SCNP formation with controlled diameters. Furthermore, the above-established intramolecular olefin metathesis approach was successfully applied to poly(acrylate), poly(styrene), and poly(ester) precursors, which proved that the present approach could be applied to a wide range of olefin-containing precursors to give SCNPs with various functional groups.

The anionic polymerization of N-(1-adamantyl)-N-4-vinylbenzylideneamine (1) and N-(2-adamantyl)-N-4-vinylbenzylideneamine (2) was performed using various initiators, such as oligo(α-methylstyryl)dipotassium, potassium naphthalenide, diphenylmethylpotassium, and diphenylmethyllithium, in THF at −78 °C for 1 h to investigate the effects of adamantyl groups on the polymerization behaviors and thermal properties of the resulting polymers. The well-defined poly(1) and poly(2) with predictable molecular weights and narrow molecular weight distributions were successfully obtained, indicating that the bulky adamantyl groups effectively protected the carbon–nitrogen double bond (C═N) from the nucleophilic attack of the initiators and the propagating chain ends. The stability of the propagating chain end of poly(1) was confirmed by the quantitative efficiencies in the postpolymerization and the sequential copolymerization with tert-butyl methacrylate. A poly(4-formylstyrene) was quantitatively formed by the acidic ...

Summary For the synthesis of a new functional polyisocyanate, the anionic polymerization of 3-chloropropyl isocyanate (3CPIC) was carried out using several initiator systems in THF at −98 °C. When a sodium benzanilide (Na-BA) cluster was used as an aggregated initiator, the initiation efficiency and polymer yield were low due to too fast propagation and cyclic trimerization compared to the initiation. A more reactive oligo(n-hexyl isocyanate)sodium/Na-BA cluster improved the initiation efficiency and polymer yield, but trimerization still occurred. A nearly quantitative yield was achieved by oligo(2-vinylpyridinyl)potassium in the presence of a large excess of sodium tetraphenylborate (NaBPh4). In this case, highly dissociating and bulky NaBPh4 reduced the propagation rate and protected the propagating chain end from trimerization through steric hindrance. This advantage of NaBPh4 was cancelled by the decreased initiation efficiency. All polymerization trials resulted in uncontrolled molecular weight properties. The chloropropyl side groups of the obtained P3CPIC reacted with polystyryllithium to generate poly(3-chloropropyl isocyanate)-graft-polystyrene (P3CPIC-g-PS) through the grafting-onto method.

Nonvolatile resistive memory devices based on a new low bandgap donor–acceptor (D–A) conjugated polymer, poly((E)-6,6′-bis(2,3-dihydrothieno[3,4-b][1,4]dioxine-5-yl)-1,1′-bis(2-octyldodecyl)-[3,3′-biindolinyi-dene]-2,2′-dione) (PIDED), which are fabricated and operated in ambient air, are reported. The D–A conjugated polymer is synthesized from 2,3-dihydrothieno[3,4-b][1,4]dioxine and isoindigo as an electron donor and an electron acceptor, respectively, using CH-arylation polymerization. The devices show nonvolatile, unipolar resistive switching behaviors with a high on/off current ratio (∼104), excellent endurance cycles (>200 cycles), and a long retention time (>104 s) in ambient air. These properties remain stable in ambient air over one year, demonstrating that the device performance is significantly unaffected by exposure to air as the isoindigo has strong electron-withdrawing character and the PIDED exhibits a high degree of crystallinity. This study may pave the way for use of practical nonvolatil...

The reactivities of 4-[(trimethylsilyl)ethynyl]styrene (A) and 4,4′-vinylphenyl-N,N-bis(4-tert-butylphenyl)benzenamine (B) were investigated by sequential anionic block copolymerization to synthesize a thermally cross-linkable block copolymer for memory device applications. From the investigation on the reactivities of the monomers, the well-defined poly(B-b-A) was synthesized in a simple manner by sequential addition of B as the first monomer and A as the second monomer using the commercially available s-butyllithium (s-BuLi) initiator in THF at −78 °C. The sequential deprotection was then performed to prepare the deprotected polymer (d-poly(B-b-A)) containing the triphenylamine group as the conducting moiety and the ethynyl group as the thermal cross-linker, and the resulting thermally cross-linked polymer was used as an active layer of the memory device. The device fabricated with cross-linked d-poly(B-b-A) exhibited the write-once-read-many times (WORM) nonvolatile memory behavior, which is governed by the space-charge-limited current (SCLC) conduction mechanism and filament formation.

The anionic block copolymerization of 4,4′-vinylphenyl-N,N-bis(4-tert-butylphenyl)benzenamine (A) with n-hexyl isocyanate (B) was performed using potassium naphthalenide (K-Naph) in THF at −78 and −98 °C in the presence of sodium tetraphenylborate (NaBPh4) to afford the well-defined block copolymers for investigating the effect of morphological structures on electrical memory performances. The well-defined functional block copolymers (PBAB) with different block ratios had predictable molecular weights (Mn = 17 700–79 100 g/mol) and narrow molecular weight distributions (Mw/Mn = 1.14–1.19). It was observed from transmission electron microscopy (TEM) that the block copolymers showed different morphological structures depending on block ratios. Although all memory devices fabricated from the resulting block copolymers with different block compositions equally exhibited nonvolatile resistive switching characteristics, which are governed by the trap-controlled space-charge-limited current (SCLC) conduction mec...

The pyridine-containing monomer 2-(4′-vinylbiphenyl-4-yl)pyridine (VBPPy), synthesized by the Suzuki coupling reaction, was successfully polymerized using diphenylmethylpotassium (DPM-K) as an initiator within 360 min at −78 °C, resulting in 100% yield and polydispersity

A series of three new low bandgap donor–acceptor–donor–acceptor/ (D–A–D–A/) polymers have been successfully synthesized based on the combination of isoindigo as the electron-deficient acceptor and 3,4-ethylenedioxythiophene as the electron-rich donor, followed by CH-arylation with different acceptors (4,7-dibromo[c][1,2,5]-(oxa, thia, and/or selena)diazole (4a-c)). These polymers were used as donor materials for photovoltaic applications. All of the polymers are highly stable and show good solubility in chlorinated solvents. The highest power conversion efficiency of 1.6% was achieved in the bulk heterojunction photovoltaic device that consisted of poly ((E)−6-(7-(benzo-[c][1,2,5]-thiadiazol-4-yl)−2,3-dihydrothieno-[3,4-b][1,4]dioxin-5-yl)−6′-(2,3-dihydrothieno-[3,4-b][1,4]-dioxin-5-yl)−1,1′-bis-(2-octyldodecyl)-[3,3′-biindolinylidene]-2,2′-dione) as the donor and PC61BM as the acceptor, with a short-circuit current density (Jsc) of 8.10 mA/cm2, an open circuit voltage (Voc) of 0.56 V and a fill factor of 35%, which indicates that these polymers are promising donors for polymer solar cell applications. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014, 52, 2926–2933

The sequential block copolymerization of 4,4′-vinylphenyl-N,N-bis(4-tert-butylphenyl)benzenamine (A) with 2-(2-(4-vinylphenyl)ethynyl)pyridine (B) was simply carried out using only potassium naphthalenide (K-Naph) as an initiator without any additives in tetrahydrofuran (THF) at −78 °C. The well-defined functional block copolymers containing A block as an electron donor and B block as a weak electron acceptor had predictable molecular weights (Mn = 8,800–14,500 g/mol) and narrow molecular weight distributions (Mw/Mn = 1.09–1.10). The bicontinuous microphase-separated film morphology of the precisely synthesized poly(B-b-A-b-B) (PBAB) with 0.71 of fpoly(A), formed by thermal annealing at 230 °C for 9 h, was expected to be a potential active layer for nonvolatile memory device applications. Indium tin oxide (ITO)/PBAB/aluminum (Al) memory devices with an 8 × 8 cross-bar array structure exhibited nonvolatile resistive switching characteristics. The memory devices showed reliable memory performance in terms of ON/OFF ratios of ∼104, endurance cycles and retention time, and statistical data with regard to cumulative probability of the switching currents and threshold voltage distribution. Filamentary conduction mechanism was proposed to explain the switching of PBAB-based memory devices. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014, 52, 2625-2632

A model chiral graft copolymer, poly(phenylacetylene)-g-poly(n-hexyl isocyanate) (PPA-g-PHIC), in which a chiral moiety is located at the end of each PHIC side chain, was synthesized. First, chiral PHIC macromonomers with a phenylacetylene end group were synthesized via living anionic polymerization using the functional initiator sodium N-(4-ethynylphenyl)benzamide (Na-4EPBA) and then end-capped using the chiral terminator (S)-2-acetoxypropionyl chloride ((S)-Ct). The molecular weights (MWs) of the PHIC macromonomers were controlled based on the feed ratio of the monomer to the initiator. Subsequent polymerization of PHIC macromonomers using Rh+(2,5-norbornadiene)[(η6-C6H5)B–(C6H5)3] (Rh(nbd)BPh4) catalyst generated chiral PPA-g-PHIC graft copolymers with varying graft strand lengths. Chiral macromonomers and graft copolymers were characterized by SEC-MALLS, NMR, and CD spectroscopy. This model chiral graft copolymer provided an excellent example of the transmission of stereochemical information from the ...

A novel amphiphilic polyisocyanate block copolymer with hydroxyl side groups was synthesized by a combination of living anionic polymerization and thiol–ene click chemistry. First, the living anionic block copolymerization of allyl isocyanate (AIC) and n-hexyl isocyanate (HIC) produced a well-defined block copolymer (PAIC-b-PHIC) as a precursor. The subsequent free-radical-mediated thiol–ene click reaction of this polymer with 2-mercaptoethanol at room temperature quantitatively converted the allyl side groups of the PAIC domain to hydroxyl groups, finally creating PAIC(OH)-b-PHIC. The amphiphilicity of PAIC(OH)-b-PHIC led to lamellar and cylindrical phase separations in the thin films cast from different solvents (THF and toluene). The functionalities and phase separation behaviors of PAIC(OH)-b-PHIC were characterized by NMR, SEC-MALLS, and TEM analysis.

To study the effect of the substituents in the N-position of the carbazole on anionic polymerization, 2-vinylcarbazole derivatives of 9-butyl-2-vinylcarbazole (NBu2VCz), 9-phenyl-2-vinylcarbazole (NPh2VCz), and 9-(pyridin-2-yl)-2-vinylcarbazole (NPy2VCz) were synthesized. The anionic polymerization of NBu2VCz and NPh2VCz using s-BuLi was performed at −78 °C with a 100% yield, but the polymerization of NBu2VCz showed a broader molecular weight distribution (Mw/Mn = 1.23) than NPh2VCz (Mw/Mn = 1.11). The anionic polymerization of NPy2VCz using s-BuLi and DPM-K had a yield below 5%. In particular, the living anionic polymerization of NPh2VCz with s-BuLi/styrene ([s-BuLi/St]0 = 0.33) shows a narrower Mw/Mn. The block copolymerization of NPh2VCz with styrene, α-methylstyrene (α-MeSt), and 2-vinylpyridine (2VP) was achieved successfully. The resulting block copolymers of PNPh2VCz-b-P2VP with fPNPh2VCz = 17.7, 34.6, 48.1, 62.4, and 82.9 were synthesized for investigation of living characteristics.

A rare self-assembly behavior is observed in a hydrophilic monomer (4-vinylpyridine) (4VP) when polymerized in water with a hydrophilic initiator that results in the production of monodisperse polymeric nanoparticles in a single step. This behavior mimics the behavior obtained with the more commonly reported amphiphilic block copolymers. The synthesis and self-assembly of homopolymer nanoparticle from 4VP without the use of any cross-linker, stabilizing agent, surfactant, or polymeric emulsifier are described along with fundamental aspects of the mechanism of this polymerization. This facile and robust procedure enabled the production of highly monodisperse P4VP nanoparticle with a tunable size ranging from 80 to 445 nm. For the first time, we have investigated the growth mechanism of these polymeric nanoparticles to clarify the mechanism of polymeric nanoparticle formation. This work also provides direct visible evidence through transmission electron microscopy (TEM) images at the nanometer scale, which ...

The block copolymerization of 4,4′-vinylphenyl-N,N-bis(4-tert-butylphenyl)benzenamine (A) with 2-(2-(4-vinylphenyl)ethynyl)pyridine (B) was performed using sec-butyllithium (s-BuLi) as an initiator in the absence and presence of potassium tert-butoxide (KOBut) in tetrahydrofuran (THF) at −78 °C. The block copolymerization was not successful in the absence of KOBut, whereas the well-defined diblock copolymer (poly(A-b-B)) containing pendent triphenylamine and ethynylpyridine was successfully synthesized in the presence of excess KOBut due to the change in the countercation from Li+ to K+ and the suppression of ion dissociation by the salt common effect. The poly(A-b-B)s had predictable molecular weights (Mn = 4,900–20,000 g/mol) and narrow molecular weight distributions (Mw/Mn = 1.13–1.15). In addition, the resulting block copolymer showed good solubility and excellent thermal properties. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 4233–4239

Amphiphilic monomers containing the isomeric pyridine moieties 3-(4-vinylphenyl)pyridine (3VPPy) and 4-(4-vinylphenyl)pyridine (4VPPy) were synthesized using the Suzuki coupling reaction. A living anionic polymerization of 3VPPy and 4VPPy was successfully performed under various conditions to overcome the limitations of anionic polymerization and to compare their properties with those of poly(2-(4-vinylphenyl)pyridine) as reported previously. Several characteristics of the resulting isomeric P3VPPy and P4VPPy were studied, such as thermal stability, solubility, and the living nature. The block copolymerization of 4VPPy with 2-vinylpyridine and MMA was carried out without additive to estimate the nucleophilicity of P4VPPy and to confirm its living nature. Additionally, each amphiphilic homopolymer of P3VPPy and P4VPPy containing both a hydrophilic pyridine unit and a hydrophobic styrene unit was tested for self-assembly behavior in a mixed solvent (THF/water) and monitored with TEM and SEM. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 3458–3469

A new cross-linkable polymer (d-PBAB), which has triphenylamine as the hole transporting moiety and ethynyl group as the thermal cross-linker, was synthesized by a living anionic polymerization and deprotection process. The thermally cross-linked d-PBAB layer had a smooth surface and excellent solvent resistance. The PLED fabricated with cross-linked d-PBAB as hole transporting layer (HTL) showed approximately one and half times higher luminance and four times higher luminous efficiency than those obtained from PLED with PEDOT:PSS. This is ascribed to better abilities of cross-linked d-PBAB to block electrons and prevent exciton quenching than those of PEDOT:PSS at the emitting layer (EML) interface. These results strongly suggested that cross-linked d-PBAB can be a promising material to replace conventional PEDOT:PSS.