Poly(p‐benzamide) having isopropyl‐substituted chiral tri(ethylene glycol) side Chain: Synthesis and helical conformation

Isopropyl‐substituted tri(ethylene glycol) is used as a chiral side chain of N‐substituted poly(p‐benzamide) in order to increase the difference of stability between the right‐ and left‐handed helical structures of the polymer. The target polymer is synthesized by the chain‐growth condensation polymerization of the corresponding monomer with an initiator using lithium 1,1,1,3,3,3‐hexamethyldisilazide as a base. A circular dichroism (CD) study of the polymer reveals that the CD signal is due to an excess of a thermodynamically controlled right‐handed helical structure of the polymer, and that the replacement of the methyl group with a bulkier isopropyl group at the side chain of poly(p‐benzamide) increases the abundance of right‐handed helical structure in chloroform. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015 , 53, 1623–1628     

Heterogeneous polycondensation for composition control of poly(p‐mercaptobenzoyl‐co‐p‐benzamide) by shearing

Composition control of aromatic poly(thioester‐amide) was examined by the reaction‐induced phase separation during polymerization of S‐acetyl‐4‐mercaptobenzoic acid (AMBA) and p‐acetylaminobenzoic acid (AABA) in aromatic solvent. The poly(thioester‐amide)s were obtained as precipitates and their yields became lower at the middle range of the content of AMBA in feed (χ_f). The contents of p‐mercaptobenzoyl (MB) moiety (χ_p) in the precipitates prepared without shearing were in good agreement with the χ_f values. In contrast to this, the χ_p values of the precipitates prepared at χ_f of 50–70 mol % under shearing were much lower than the χ_f values. The reaction rate of AMBA increased with shearing, whereas that of AABA was unchanged by shearing. This shearing effect on the reaction rates accelerated to form the homo‐oligomers. The solubility of MB oligomers enhanced by shearing, whereas that of p‐benzamide oligomers did not enhance owing to the strong interaction through hydrogen bonding. The MB oligomers were inhibited to be precipitated, resulting in the lower χ_p values than the χ_f values. The composition could be controlled by the application of the shearing to the heterogeneous polymerization. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 4301–4308     

Synthesis and helical conformation of poly(N‐propargylamides) carrying L‐aspartic acid in the side chain

Aspartic acid‐based novel poly(N‐propargylamides), i.e., poly[N‐(α‐tert‐butoxycarbonyl)‐L ‐aspartic acid β‐benzyl ester N′‐propargylamide] [poly( 1 )] and poly[N‐(α‐tert‐butoxycarbonyl)‐L ‐aspartic acid α‐benzyl ester N′‐propargylamide] [poly( 2 )] with moderate molecular weights were synthesized by the polymerization of the corresponding monomers 1 and 2 catalyzed with (nbd)Rh⁺[η⁶‐C₆H₅B^?(C₆H₅)₃] in CHCl₃ at 30 °C for 2 h in high yields. The chiroptical studies revealed that poly( 1 ) took a helical structure in DMF, while poly( 2 ) did not in DMF but did in CH₂Cl₂, CHCl₃, and toluene. The helicity of poly( 1 ) and poly( 2 ) could be tuned by temperature and solvents. Poly( 2 ) underwent solvent‐driven switch of helical sense, accompanying the change of the tightness. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 5168–5176, 2005     

Synthesis and electrochemical and electroluminescent properties of N‐phenylcarbazole‐substituted poly(p‐phenylenevinylene)

An N‐phenylcarbazole‐containing poly(p‐phenylenevinylene) (PPV), poly[(2‐(4′‐carbazol‐9‐yl‐phenyl)‐5‐octyloxy‐1,4‐phenylenevinylene)‐alt‐(2‐(2′‐ethylhexyloxy)‐5‐methoxy‐1,4‐phenylenevinylene)] (Cz‐PPV), was synthesized, and its optical, electrochemical, and electroluminescent properties were studied. The molecular structures of the key intermediates, the carbazole‐containing boronic ester and the dialdehyde monomer, were crystallographically characterized. The polymer was soluble in common organic solvents and exhibited good thermal stability with a 5% weight loss at temperatures above 420 °C in nitrogen. A cyclic voltammogram showed the oxidation peak potentials of both the pendant carbazole group and the PPV main chain, indicating that the hole‐injection ability of the polymer would be improved by the introduction of the carbazole‐functional group. A single‐layer light‐emitting diode (LED) with a simple configuration of indium tin oxide (ITO)/Cz‐PPV (80 nm)/Ca/Al exhibited a bright yellow emission with a brightness of 1560 cd/m² at a bias of 11 V and a current density of 565 mA/cm². A double‐layer LED device with the configuration of ITO/poly(3,4‐ethylenedioxy‐2,5‐thiophene):poly (styrenesulfonic acid) (60 nm)/Cz‐PPV (80 nm)/Ca/Al gave a low turn‐on voltage at 3 V and a maximum brightness of 6600 cd/m² at a bias of 8 V. The maximum electroluminescent efficiency corresponding to the double‐layer device was 1.15 cd/A, 0.42 lm/W, and 0.5%. The desired electroluminescence results demonstrated that the incorporation of hole‐transporting functional groups into the PPVs was effective for enhancing the electroluminescent performance. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 5765–5773, 2005     

Synthesis and double doping behavior of a poly(p‐phenylenevinylene)s bearing conjugated side chains

A poly(p‐phenylenevinylene) derivative bearing conjugated side chains (polyCPV) was synthesized by Migita‐Kosugi‐Stille type coupling polycondensation reaction. This polymer contains phenylenevinylene units in both the main chain and the side chains. UV–vis absorption and fluorescence emission spectroscopies revealed a well‐developed π‐conjugation of the polyCPV. The absorption band of the polymer was extended to long wavelengths. A fluorescent emission maximum of polyCPV is located at considerably longer wavelengths than that of the conjugated side chain monomer. Electron spin resonance measurements of polyCPV confirmed generation of charge species in both the main chain and the side chains via iodine doping. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012     

Synthesis and properties of poly(sulfone‐arylate) copolymers

Poly(sulfone‐arylate) was synthesized in a reaction between dihydroxy polysulfone prepolymers and either diphenyl terephthalate or terephthaloyl chloride. The dihydroxy polysulfone prepolymers had molecular weights of 2000 and 4000 g/mol. The polymerization with diphenyl terephthalate was carried out at high temperature (280 °C) in the presence of a catalyst, whereas the polymerization with terephthalic chloride was conducted in solution at low temperature in the presence of an acid acceptor. High‐molecular weight copolymers (η_inh ～ 0.60 dL/g) could be obtained through both methods. The copolymers were characterized by Fourier transform infrared spectroscopy, nuclear magnetic resonance, DMA, and differential scanning calorimetry measurements and were found to exhibit high T_g values. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 3904–3913, 2009     

Effects of different composition ratio on the dielectric relaxation and dynamic mechanical properties of poly(ω‐dodecalactam‐co‐ε‐caprolactam‐co‐propylene oxide) copolymers

The molecular dynamics of new poly (ω‐dodecalactam‐co‐ε‐caprolactam‐co‐propylene oxide) copolymers (DL/CL/PAC) has been investigated by using dynamic mechanical thermal analysis (DMTA) and dielectric relaxation spectroscopy (DRS) measurements. The copolymers were synthesized via anionic polymerization of relevant lactams activated with carbamoyl derivatives of telechelic hydroxyl terminated polypropylene oxide with isophorone diisocyanate (PAC). The calorimetric, X‐ray diffraction, and DMTA measurements were performed to recognize the influence of the composition ratio and the type of PAC on the physical, thermal, and mechanical properties of the synthesized copolymers. The DRS was used to study the frequency dependence of the dielectric permittivity of some isotherms from ?110 to 145 °C. Copolymerization of ε‐caprolactam with about 10 wt % ω‐dodecalactam results in a copolymer that has lower water absorption, a melting point close to that of polyamide 6 and has a high enough degree of crystallinity in respect to high storage modulus. Five dielectric relaxations have been observed in the dielectric spectra, three at lower temperature and two at higher temperature. The copolymers have two glass transition temperatures for polyamide segments and polyether blocks, indicating microphase separation in the copolymers. Other studies directed toward molecular dynamics of polyamide DL/CL/PAC copolymers have not been reported. © 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2010     

Synthesis and properties of processable conducting copolymers from N‐ethylaniline with aniline

Copolymers were synthesized through the chemically oxidative polymerization of N‐ethylaniline (EA) and aniline (AN) in five acid aqueous media. The polymerization yield, intrinsic viscosity, molecular weight, solubility, solvatochromism, electrical conductivity, and mechanical properties of the copolymer films were systematically studied through changes in the comonomer ratio, polymerization temperature, oxidant, oxidant/monomer ratio, and acid medium. Open‐circuit‐potential and temperature measurements of the polymerization solutions showed that the polymerization rate depended on the EA content, and the polymerization was an exothermic reaction. The resultant copolymers were characterized in detail with IR, ultraviolet–visible, and ¹H NMR spectroscopy, gel permeation chromatography, wide‐angle X‐ray diffractometry, and scanning electron microscopy. The reactivity ratios of the monomer pair were calculated from the ¹H NMR spectra of the copolymers formed at a low conversion. The polymers exhibited good solubility and interesting solvatochromism in most of the solvents and variable conductivity with the EA/AN ratio and doping state. The conductivity of the HCl‐doped copolymers increased monotonically from 5.61 × 10^?7 to 2.55 × 10^?1 S/cm with decreasing EA content from 100 to 0 mol % and showed a percolation transition between EA concentrations of 20 and 30 mol %. The EA/AN copolymers also had excellent film formability and flexibility together with high mechanical and oxygen‐enriching properties. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 6109–6124, 2004     

Effect of N‐methyl amide linkage on hydrogen bonding behavior and water transport properties of partially N‐methylated random aromatic copolyamides

The synthesis, conformational preferences, hydrogen bonding behaviors, and membrane properties of new partially N‐methylated random aromatic copolyamides were reported. These copolyamides were prepared by the low temperature polycondensations of isophthaloyl chloride with 3,5‐diaminobenzoic acid, N,N'‐dimethyl‐4,4'‐diaminodiphenyl ether (MDAE), and 4,4'‐diaminodiphenyl ether. The incorporation of the N‐methyl amide linkages into the polymer backbone decreased the contents of the cis conformation in the N‐methyl amide linkages and suppressed the hydrogen bondings among the amide linkages. Furthermore, the surface hydrophilicity of the copolyamides evaluated by water contact angle measurements decreased with increasing the MDAE unit in the polymer backbone. These experimental results indicated that the suppression of the hydrogen bonding and the existence of the tertiary amide linkage in the cis conformation induced the loose packing of the polymer chains. As a result, the incorporation of the N‐methyl amide linkage increased water flux and decreased salt rejection. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 3453–3462     

Synthesis and optoelectronic properties of liquid‐crystalline copolymers based on fluorene and triphenylamine‐containing oligo(p‐phenylenevinylene) derivatives for white light emission

A series of novel liquid‐crystalline copolymers based on fluorene and triphenylamine‐containing oligo(p‐phenylenevinylene) derivatives have been synthesized according to the Suzuki polymerization method. The structures, optical and electrochemical properties of the copolymers were characterized by ¹H NMR, ¹³C NMR, GPC, UV–vis, photoluminescence (PL) spectroscopy, and cyclic voltammetry (CV), respectively. The thermotropic phase behavior of the copolymers was investigated by using differential scanning calorimetry (DSC) and polarized optical microscope (POM). All of the copolymers exhibit thermally liquid crystalline properties and represent the characteristic Schlieren textures in a wide temperature range. The effects of the concentrations and chain length of the oligo(phenylenevinylene) units on the thermal properties, liquid crystalline, photo‐ and electroluminescent properties of the copolymers have been investigated in details. Among the copolymers‐based devices with a configuration of ITO/PEDOT:PSS/polymers/Ca/Al, the device based on PF‐LOPV05 exhibits the lowest turn‐on voltage of 3 V and the maximum brightness of 210 cd/m² at 8.3 V. A single layer device based on the blend of PF/PF‐LOPV05 emits white electroluminescence with CIE coordinates of (0.30, 0.35) at 8 V. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 3296–3308, 2009     

Synthesis and characterization of graft copolymers containing poly(p-phenylene) main chains and mesogen-jacketed liquid-crystalline polystyrene side chains

A series of novel comblike mesogen-jacketed liquid-crystalline graft copolymers, poly(p-phenylene)-g-poly{2,5-bis[(4-methoxyphenyl)oxycarbonyl]styrene} (PPP-g-PMPCS) copolymers, have been designed and successfully synthesized by a Yamamoto coupling reaction and subsequent atom transfer radical polymerization (ATRP). ¹H NMR spectroscopy, ultraviolet–visible spectra, and gel permeation chromatography (GPC) have been used to confirm the molecular structure of the macroinitiator and the copolymers. A study of the polymerization kinetics of ATRP has shown that the molecular weight of the copolymer increases linearly with the conversion of the monomer, whereas the polydispersity remains narrow (≤1.28), indicating that the ATRP of 2,5-bis[(4-methoxyphenyl)oxycarbonyl]styrene is well controlled. Thermogravimetric analysis and differential scanning calorimetry (DSC) measurements have indicated that the PPP-g-PMPCS copolymers have better thermal stabilities than the macroinitiator, and their thermal stabilities increase with increasing molecular weight. The liquid-crystalline behavior has been examined with polarized optical microscopy, DSC, one-dimensional wide-angle X-ray diffraction (1D WAXD), and two-dimensional wide-angle X-ray diffraction (2D WAXD). The results show that all the comblike copolymers exhibit obvious liquid-crystalline behaviors, even though the GPC molecular weight of the segments of poly{2,5-bis[(4-methoxyphenyl)oxycarbonyl]styrene} (PMPCS) have been determined to be far less than the critical value of linear PMPCS. Moreover, 1D WAXD measurements show that the temperature at which the comblike mesogen-jacketed liquid-crystalline copolymers can transform into a liquid-crystalline phase is low; about 20 °C in comparison with the linear ones. 2D WAXD analysis has revealed that these comblike copolymers should be assigned to a hexatic columnar nematic (Φ_HN) phase. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 2543–2555, 2007     

Aggregation,gelation instability,and morphologies of diblock copolymers consisting of poly(p‐benzamide) and poly(m‐benzamide)

The solution, gelation, and morphological properties of monodisperse aromatic polyamide diblock copolymers consisting of poly(p‐benzamide) (PpBA), poly(m‐benzamide) (PmBA), and poly(N‐octyl m‐benzamide) (POmBA) were investigated. The block copolymers of these polymers, PpBA‐block‐POmBA and PmBA‐block‐POmBA, formed spherical micelles or amorphous aggregates in many solvents in addition to physical gels at concentrations higher than 5 wt %. A temperature‐induced sol‐gel transition was also exhibited for PpBA‐block‐POmBA in solvents with high boiling points such as N,N‐dimethylacetamide and N‐methylpyrrolidone (NMP), although the transition was not entirely thermoreversible; the transition temperature decreased by annealing at ～80 °C. Dynamic light scattering measurements of the PpBA‐block‐POmBA/NMP solutions revealed that metastable micelles in the sol state reorganized into smaller micelles upon annealing at 90 °C. The block copolymer, which forms strong associations, exhibited some transient structure as indicated by the need to sufficiently anneal the solution to reach equilibrium. Network‐like patterns with characteristic length of ～10 μm appeared on the gel surfaces upon evaporation of volatile solvents such as dichloromethane and chloroform, in which the copolymers were observed to aggregate. The unique properties of the copolymers originate from interactions between the highly polar N? H aromatic polyamide blocks. © 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 48: 1732–1739, 2010     

Synthesis of achiral PEG‐PANI rod‐coil block copolymers and their helical superstructures

Poly(ethylene glycol) (PEG) was modified with aniline groups at both the end, and then PEG‐PANI rod‐coil block polymers have been synthesized by polymerization of the aniline with the aniline‐modified PEG. FTIR, NMR, and elemental analysis provided the chemical strucutre of the as‐prepared polymers. The achiral rod‐coil copolymer could form different superstructures by means of self‐assembly when adding diethyl ether into its THF solution and the length of PANI segments is a key factor to the superstructures. AFM measurements revealed that they form spring‐like helical superstructures from the short PANI‐containing copolymers while these form fibrous helical superstructures from the longer PANI‐containing copolymer. A possible mechanism of the helical superstructures is suggested in this article and the driving force is believed the π–π stacking of the rigid segment of the copolymers. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 12–20, 2008     

Synthesis and light‐emitting properties of carbazole‐based copolymers bearing cyano‐substituted arylenevinylene chromophore

Two arylenevinylene compounds bearing the cyano group at α‐position ( 6 ) and β‐position ( 9 ) from the dialkoxylphenylene unit were synthesized, in which the molecular termini were functionalized with 3‐bromocarbazole. The Suzuki coupling copolymerization of these compounds with 1,4‐bis[(3′‐bromocarbazole‐9′‐yl)methylene]‐2,5‐didecyloxybenzene and 9,9‐dihexylfluorene‐2,7‐bis(boronic acid) was carried out to obtain copolymers ( cp67 and cp97 ) containing the cyano‐substituted arylenevinylene fluorophore of 7 mol %. Model compounds ( 6 ′ and 9 ′) corresponding to the arylenevinylene fluorophore were also prepared. The UV spectra of copolymers resembled that of homopolymer hp with no arylenevinylene segment in both CHCl₃ solution and thin film. The emission maxima of copolymers in CHCl₃ (394 nm) agreed with that of homopolymer indicating that the emission bands originated from the carbazole‐fluorene‐carbazole segment. The emission maximum wavelength of copolymer cp67 in thin film (477 nm) indicated fluorescence from the cyano‐substituted arylenevinylene fluorophore because of the occurrence of fluorescence resonance electron transfer. In contrast, copolymer cp97 showed fluorescence at 528 nm to suggest the formation of a new emissive species such as a charge‐transfer complex (exciplex). © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 91–98, 2010     

Synthesis and photovoltaic properties of two‐dimensional D‐A copolymers with conjugated side chains

Four novel two‐dimensional (2D) donor–acceptor (D‐A) type copolymers with different conjugated side chains, P1 , P2 , P3 , and P4 (see Fig. 1 ), are designed and synthesized for the application as donor materials in polymer solar cells (PSCs). To the best of our knowledge, there were few reports to systematically study such 2D polymers with D‐A type main chains in this area. The optical energy band gaps are about 2.0 eV for P1 – P3 and 1.67 eV for P4 . PSC devices using P1 – P4 as donor and [6,6]‐phenyl‐C₆₁‐butyric acid methyl ester as acceptor in a weight ratio of 1:3 were fabricated and characterized to investigate the photovoltaic properties of the polymers. Under AM 1.5 G, 100 mA/cm² illumination, a high open‐circuit voltage (V_oc) of 0.9 V was recorded for P3 ‐based device due to its low HOMO level, and moderate fill factor was obtained with the best value of 58.6% for P4 ‐based device, which may mainly be the result of the high hole mobility of the polymers (up to 1.82 × 10^?3 cm²/V s). © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011     

Alternating copolymers of 2,6‐bis(p‐dihexylaminostyryl)anthracene‐9,10‐diyl and N‐octylcarbazole with large two‐photon cross sections

We report the synthesis, thermal, one‐ and two‐photon properties of poly(2,6‐bis(p‐dihexylaminostyryl)anthracene‐9,10‐diyl‐alt‐N‐octylcarbazole‐3,6‐/2,7‐diyl) ( P1/P2 ). The as‐synthesized polymers exhibit number‐average molecular weights of 1.7 × 10⁴ for P1 and 2.1 × 10⁴ g/mol for P2 . They emit strong one‐ and two‐photon excitation fluorescence with the peak around 502 nm, and the fluorescence quantum yields around 0.76 in chloroform. In film state, P1 and P2 show different red‐shift emission with the peaks at 512 nm and 523 nm, respectively. The DSC measurement reveals that as‐synthesized polymers are all amorphous aggregates with the glass transition temperatures of 131 °C for P1 and 152 °C for P2 . The solution two‐photon absorption (TPA) properties of P1 and P2 in chloroform are measured by the two‐photon‐induced fluorescence method using femtosecond laser pulses (120 fs). The TPA cross sections (δ) are measured over the range of 700–900 nm. The maximal δ of P1 and P2 all appear at ～800 nm and are 1010 GM and 940 GM per repeating unit, respectively. This suggests that no notable interactions among structure units that impair their fluorescence and TPA properties, and the polymers with large δ can be obtained by using the high TPA‐active units as building blocks. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010     

One‐ and two‐dimensional NMR characterization of N‐vinyl‐2‐pyrrolidone/methyl acrylate copolymers

N‐vinyl‐2‐pyrrolidone/methyl acrylate (V/M) copolymers were prepared by free‐radical bulk polymerization using benzoyl peroxide as an initiator. The copolymer composition of these copolymers was calculated from ¹H NMR spectra. The radical reactivity ratios for N‐vinyl‐2‐pyrrolidone (V) and methyl acrylate (M) were r_V = 0.09, r_M = 0.44. These reactivity ratios for the copolymerization of V and M were determined using the Kelen–Tudos and nonlinear least‐squares error‐in‐variable methods. The ¹³C{¹H} and ¹H NMR spectra of these copolymers overlapped and were complex. The complete spectral assignment of the ¹³C and ¹H NMR spectra were done with distortionless enhancement by polarization transfer and two dimensional ¹³C‐¹H heteronuclear single quantum correlation spectroscopic experiments. The two‐dimensional ¹H‐¹H homonuclear total correlation spectroscopic NMR spectrum showed the various bond interactions, thus inferring the possible structure of the copolymers. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 2225–2236, 2002