Pure and complex nanostructures using poly[bis(triiso‐propylsilylethynyl) benzodithiophene‐bis(decyltetradecyl‐thien) naphthobisthiadiazole], carbon nanotubes and reduced graphene oxide for high‐performance polymer solar cells

Crystallization of poly[bis(triiso‐propylsilylethynyl) benzodithiophene‐bis(decyltetradecyl‐thien) naphthobisthiadiazole] (PBDT‐TIPS‐DTNT‐DT) was investigated in supramolecules based on carbon nanotubes (CNTs) and reduced graphene oxide (rGO) and their grafted derivatives. The principal peaks of PBDT‐TIPS‐DTNT‐DT crystals were in the range 3.50°–3.75°. By grafting the surface of the carbonic materials, the assembling of polymer chains decreased because of hindrance of poly(3‐dodecylthiophene) (PDDT) grafts against π‐stacking. The diameters of CNT/polymer and CNT‐g‐PDDT/polymer supramolecules were 160 and 100 nm. The rGO/polymer supramolecules had the highest melting point (T_m = 282 °C) and fusion enthalpy (ΔH_m = 25.98 J g^?1), reflecting the largest crystallites and the most ordered constituents. Nano‐hybrids based on grafted rGO (276 °C and 28.26 J g^?1), CNT (275 °C and 27.32 J g^?1) and grafted CNT (268 °C and 22.17 J g^?1) were also analyzed. T_m and ΔH_m values were significantly less in corresponding melt‐grown systems. The nanostructures were incorporated in active layers of PBDT‐TIPS‐DTNT‐DT:phenyl‐C₇₁‐butyric acid methyl ester (PC₇₁BM) solar cells to improve the photovoltaic features. The best results were detected for PBDT‐TIPS‐DTNT‐DT:PC₇₁BM:rGO/polymer systems having J_sc = 13.11 mA cm^?2, fill factor 60% and V_oc = 0.71 V with an efficacy of 5.58%. On grafting the rGO and CNT, efficiency reductions were 12.01% (5.58%–4.91%) and 9.34% (4.07%–3.69%), respectively. © 2019 Society of Chemical Industry     

Well‐functioned photovoltaics based on nanofibers composed of PBDT‐TIPS‐DTNT‐DT and graphenic precursors thermally modified by polythiophene,polyaniline and polypyrrole

Reduced graphene oxide nanosheets modified by conductive polymers including polythiophene (GPTh), polyaniline (GPANI) and polypyrrole (GPPy) were prepared using the graphene oxide as both substrate and chemical oxidant. UV–visible and Raman analyses confirmed that the graphene oxide simultaneously produced the reduced graphene oxide and polymerized the conjugated polymers. The prepared nanostructures were subsequently electrospun in mixing with poly(3‐hexylthiophene) (P3HT)/phenyl‐C71‐butyric acid methyl ester (PC₇₁BM) and poly[bis(triisopropylsilylethynyl)benzodithiophene‐bis(decyltetradecylthien)naphthobisthiadiazole] (PBDT‐TIPS‐DTNT‐DT)/PC₇₁BM components and embedded in the active layers of photovoltaic devices to improve the charge mobility and efficiency. The GPTh/PBDT‐TIPS‐DTNT‐DT/PC₇₁BM devices demonstrated better photovoltaic features (J_sc = 11.72 mA cm^?2, FF = 61%, V_oc = 0.68 V, PCE = 4.86%, μ_h = 8.7 × 10^?3 cm² V^–1 s^?1 and μ_e = 1.3 × 10^?2 cm² V^–1 s^?1) than the GPPy/PBDT‐TIPS‐DTNT‐DT/PC₇₁BM (J_sc = 10.30 mA cm^?2, FF = 60%, V_oc = 0.66 V, PCE = 4.08%, μ_h = 1.4 × 10^?3 cm² V^–1 s^?1 and μ_e = 8.9 × 10^?3 cm² V^–1 s^?1) and GPANI/PBDT‐TIPS‐DTNT‐DT/PC₇₁BM (J_sc = 10.48 mA cm^?2, FF = 59%, V_oc = 0.65 V, PCE = 4.02%, μ_h = 8.6 × 10^?4 cm² V^–1 s^?1 and μ_e = 7.8 × 10^?3 cm² V^–1 s^?1) systems, assigned to the greater compatibility of PTh in the nano‐hybrids and the thiophenic conjugated polymers in the bulk of the nanofibers and active thin films. Furthermore, the PBDT‐TIPS‐DTNT‐DT polymer chains (3.35%–5.04%) acted better than the P3HT chains (2.01%–3.76%) because of more complicated conductive structures. © 2019 Society of Chemical Industry     

Efficiency above 6% in poly(3‐hexylthiophene):phenyl‐C‐butyric acid methyl ester photovoltaics via simultaneous addition of poly(3‐hexylthiophene) based grafted graphene nanosheets and hydrophobic block copolymers

A combination of reduced graphene oxide (rGO) nanosheets grafted with regioregular poly(3‐hexylthiophene) (P3HT) (rGO‐g‐P3HT) and P3HT‐b‐polystyrene (PS) block copolymers was utilized to modify the morphology of P3HT:[6,6]‐phenyl‐C71‐butyric acid methyl ester (PC71BM) active layers in photovoltaic devices. Efficiencies greater than 6% were acquired after a mild thermal annealing. To this end, the assembling of P3HT homopolymers and P3HT‐b‐PS block copolymers onto rGO‐g‐P3HT nanosheets was investigated, showing that the copolymers were assembled from the P3HT side onto the rGO‐g‐P3HT nanosheets. Assembling of P3HT‐b‐PS block copolymers onto the rGO‐g‐P3HT nanosheets developed the net hole and electron highways for charge transport, thereby in addition to photoluminescence quenching the charge mobility (μ_h and μ_e) values increased considerably. The best charge mobilities were acquired for the P3HT₅₀₀₀₀:PC71BM:rGO‐g‐P3HT₅₀₀₀₀:P3HT₇₀₀₀‐b‐PS₁₀₀₀ system (μ_h = 1.9 × 10^?5 cm² V^–1 s^–1 and μ_e = 0.8 × 10^?4 cm² V^–1 s^–1). Thermal annealing conducted at 120 °C also further increased the hole and electron mobilities to 9.8 × 10^?4 and 2.7 × 10^?3 cm² V^–1 s^–1, respectively. The thermal annealing acted as a driving force for better assembly of the P3HT‐b‐PS copolymers onto the rGO‐g‐P3HT nanosheets. This phenomenon improved the short circuit current density, fill factor, open circuit voltage and power conversion efficiency parameters from 11.13 mA cm^?2, 0.63 V, 62% and 4.35% to 12.98 mA cm^?2, 0.69 V, 68% and 6.09%, respectively. © 2019 Society of Chemical Industry     

Improved stability in P3HT:PCBM photovoltaics by incorporation of well‐designed polythiophene/graphene compositions

Morphological and photovoltaic stabilities of poly(3‐hexylthiophene) (P3HT):phenyl‐C₆₁‐butyric acid methyl ester (PC₇₁BM) solar cells were investigated in pristine and modified states. To this end, four types of patterned/assembled nanostructures, namely reduced graphene oxide (rGO)‐g‐poly(3‐dodecylthiophene)/P3HT patched‐like pattern, rGO–polythiophene/P3HT/PC₇₁BM nanofiber, rGO‐g‐P3HT/P3HT cake‐like pattern and supra(polyaniline (PANI)‐g‐rGO/P3HT), were designed on the basis of rGO and various conjugated polymers. Intermediately covered rGO nanosheets by P3HT crystals (supra(PANI‐g‐rGO/P3HT)) performed better than sparsely (patched‐like pattern) and fully (cake‐like pattern) covered ones in P3HT:PC₇₁BM solar cell systems. Supra(PANI‐g‐rGO/P3HT) nanohybrids largely phase‐separated in active layers (root mean square = 0.88 nm) and also led to the highest performance (power conversion efficiency of 5.74%). The photovoltaic characteristics demonstrated decreasing trends during air aging for all devices, but with distinct slopes. The steepest decreasing plots were obtained for the unmodified P3HT:PC₇₁BM devices (from 1.77% to 0.28%). The two supramolecules with the most ordered structures, that is, cake‐like pattern (10.12 mA cm^?2, 51%, 0.58 V, 2.2 × 10^?6 cm² V^?1 s^?1, 4.3 × 10^?5 cm² V^?1 s^?1, 0.69 nm and 2.99%) and supra(PANI‐g‐rGO/P3HT) (12.51 mA cm^?2, 57%, 0.63 V, 1.2 × 10^?5 cm² V^?1 s^?1, 3.4 × 10^?4 cm² V^?1 s^?1, 0.82 nm and 4.49%), strongly retained morphological and photovoltaic stabilities in P3HT:PC₇₁BM devices after 1 month of air aging. According to the morphological, optical, photovoltaic and electrochemical results, the supra(PANI‐g‐rGO/P3HT) nanohybrid was the best candidate for stabilizing P3HT:PC₇₁BM solar cells. © 2020 Society of Chemical Industry     

Impact of alkyl side chain on the photostability and optoelectronic properties of indacenodithieno[3,2‐b]thiophene‐alt‐naphtho[1,2‐c:5,6‐ c′]bis[1,2,5]thiadiazole medium bandgap copolymers

Three donor‐π‐acceptor (D‐π‐A) type alternating conjugated polymers, namely PIDTT‐DTNT‐C16, PIDTT‐DTNT‐HD and PIDTT‐DTNT‐OD bearing the same backbone of indacenodithieno[3,2‐b]thiophene (IDTT) as the D unit and naphtho[1,2‐c:5,6‐c′]bis[1,2,5]thiadiazole (NT) as the A moiety but with different flexible side chain (n‐hexadecyl (C16), 2‐hexyldecyl (HD) and 2‐octyldodecyl (OD)) substituted thiophene employed as π‐bridges, were synthesized and characterized. The effects of the side chain on absorption, photostability, energy levels, aggregation, backbone conformation, morphology and photovoltaic properties were systematically investigated. Because moderate D and strong A units were selected to construct the polymer backbone, a medium optical bandgap (ca. 1.66 eV) and low‐lying highest occupied molecular orbital energy level (E_HOMO ≈ ?5.36 V), thus resulting in a relatively higher open‐circuit voltage (V_OC) of 0.80–0.83 V, were achieved. It was found that the side chain gave rise to an insignificant impact on absorption, aggregation and photostability in chlorobenzene solution and energy levels but a non‐negligible influence on absorption, photostability and aggregation behavior in the film state. It was found that PIDTT‐DTNT‐C16 with the densest and most ordered packing structure exhibited the best photostability. Inverted bulk heterojunction polymer solar cells based on PIDTT‐DTNT‐HD:PC₆₁BM ([6,6]‐phenyl‐C₆₁‐butyric acid methyl ester) showed at least a 1.5‐fold increase in power conversion efficiency, chiefly originating from its slightly improved absorption, more balanced μ_h/μ_e ratio and favorable morphology of the active layer as a result of incorporating branched HD side chains into the IDTT‐alt‐DTNT backbone. © 2019 Society of Chemical Industry     

Synthesis of amphiphilic isoindigo co‐polymers for organic field effect transistors: A comparative study

In this work, the amphiphilic isoindigo (am‐iInd) based conjugated polymers namely poly(am‐iInd‐DT) and poly(am‐iInd‐TT) and their regular counterpart poly(reg‐iInd‐DT) and poly(reg‐iInd‐TT) were synthesized to compare their opto‐electronic and charge transport properties. They were used to fabricate organic field effect transistors. Charge transport properties in conjugated polymers depend upon intermolecular interaction which is strongly affected by the nature of side chains. The amphiphilic nature of the conjugated polymers has little impact on the charge transport properties. The charge carrier mobility of amphiphilic conjugated polymers was comparable with the regular polymers except poly(reg‐iInd‐DT) which can be correlated by X‐ray diffraction and thin film morphology. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45461.     

Design and synthesis of thieno[3,4‐c]pyrrole‐4,6‐dione based conjugated copolymers for organic solar cells

A new series of conjugated copolymers (PBDT‐TPD , PBDT ‐Th‐TPD , PBDT‐TT‐TPD ) containing donor–acceptor (D ? A) structure electron‐rich benzo[1,2‐b :4,5‐b ′]dithiophene (BDT ) units with branched alkyl thiophene side chains and electron‐deficient 5‐(2‐octyl)‐4H ‐thieno[3,4‐c ]pyrrole‐4,6(5H )‐dione (TPD) units was designed and synthesized. To tune the optical and electrochemical properties of the copolymers, the conjugation length of the copolymers was extended by introducing π‐conjugated spacers such as thiophene and thieno[3,2‐b ]thiophene units. It was observed that PBDT‐TPD showed broader absorption spectra in the longer wavelength region and the absorption maximum was red‐shifted compared to that of PBDT‐Th‐TPD, PBDT‐TT‐TPD. Stokes shifts were calculated to be 52 nm for PBDT‐TPD, 153 nm for PBDT‐Th‐TPD and 146 nm for PBDT‐TT‐TPD. Further, PBDT‐TPD exhibited a deeper highest occupied molecular orbital energy level of ?5.53 eV as calculated by cyclic voltammetry. Bulk heterojunction solar cells fabricated using PBDT‐TPD as donor material exhibited a power conversion efficiency of 1.92%. © 2017 Society of Chemical Industry     

Investigation of molecular interaction between single‐walled carbon nanotubes and conjugated polymers

Single‐walled carbon nanotubes (SWNTs) have unique properties such as high electrical conductivity and high tensile strength. Their composites with polymers have a great role in new sciences such as organic solar cells and ultrastrong lightweight materials. In this article, molecular dynamic simulations with polymer consistent force field are performed to study the interaction between SWNTs and conjugated polymers including poly(2‐methoxy‐5‐(3‐7‐dimethyloctyloxy)‐1,4‐phenylenevinylene) (MDMO‐PPV), poly(3‐hexythiophene) (P3HT), and poly[(9,9′‐dioctylfluorenyl‐2,7‐diyl)‐co‐bis(N,N′‐(4,butylphenyl))bis(N,N′‐phenyl‐1,4‐phenylene)diamine] (PFB). We computed the interaction energy and morphology of polymers adsorbed to the surface of SWNTs was studied by the radius of gyration (Rg). The influence of important factors such as SWNT radius, chirality, and the temperature on the interfacial adhesion of SWNT–polymer and Rg of polymers were studied. We found that the strongest interaction between the SWNTs and these polymers was, first observed for P3HT, then MDMO‐PPV, and finally PFB. Our results showed that the interaction energy is influenced by SWNT radius and the specific monomer structure of the polymers, but the effects of chirality and temperature are very weak. In addition, we found that the temperature, chirality, and radius have not any important effect on the radius of gyration. POLYM. COMPOS.,, 2012. © 2012 Society of Plastics Engineers     

Nonisothermal crystallization behaviors of poly(3‐hexylthiophene)/reduced graphene oxide nanocomposites

Poly(3‐hexylthiophene) (P3HT)/reduced graphene oxide (rGO) nanocomposites were prepared through in situ reduction of graphene oxide in the presence of P3HT. The nonisothermal crystallization behaviors of P3HT and P3HT/rGO nanocomposites were investigated by differential scanning calorimetry. The Avrami, Ozawa, and Mo models were used to analyze the nonisothermal kinetics. The addition of rGO remarkably increased the crystallization peak temperature and crystallinity of P3HT, but the crystallization half‐time revealed little variation. The crystallization activation energies were calculated by the Kissinger equation. The results suggested that rGO plays a twofold role in the nonisothermal crystallization of P3HT, that is, rGO promotes the crystallization of P3HT as nucleating agent, and meanwhile, it also restricts the motion of P3HT chains. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Synthesis and characterization of new optically active poly(amide‐imide‐urethane) thermoplastic elastomers,derived from 4,4′‐(hexafluoroisopropylidene)‐N,N′‐bis(phthaloyl‐L‐leucine‐p‐aminobenzoic acid) and PEG‐MDI

A new class of optically active poly(amide‐imide‐urethane) was synthesized via two‐step reactions. In the first step, 4,4′‐methylene‐bis(4‐phenylisocyanate) (MDI) reacts with several poly(ethylene glycols) (PEGs) such as PEG‐400, PEG‐600, PEG‐2000, PEG‐4000, and PEG‐6000 to produce the soft segment parts. On the other hand, 4,4′‐(hexafluoroisopropylidene)‐N,N′‐bis(phthaloyl‐L ‐leucine‐p‐amidobenzoic acid) (2) was prepared from the reaction of 4,4′‐(hexafluoroisopropylidene)‐N,N′‐bis(phthaloyl‐L ‐leucine) diacid chloride with p‐aminobenzoic acid to produce hard segment part. The chain extension of the above soft segment with the amide‐imide 2 is the second step to give a homologue series of poly(amide‐imide‐urethanes). The resulting polymers with moderate inherent viscosity of 0.29–1.38 dL/g are optically active and thermally stable. All of the above polymers were fully characterized by IR spectroscopy, elemental analyses, and specific rotation. Some structural characterization and physical properties of this new optically active poly(amide‐imide‐urethanes) are reported. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 2288–2294, 2004     

Synthesis and characterization of new thermally stable poly(ester‐imide)s derived from 2,2′‐bis(4‐trimellitimidophenoxy)biphenyl and 2,2′‐bis(4‐trimellitimidophenoxy)‐1,1′‐binaphthyl and various aromatic dihydroxy compounds

A series of new alternating aromatic poly(ester‐imide)s were prepared by the polycondensation of the preformed imide ring‐containing diacids, 2,2′‐bis(4‐trimellitimidophenoxy)biphenyl (2a) and 2,2′‐bis(4‐trimellitimidophenoxy)‐1,1′‐binaphthyl (2b) with various aromatic dihydroxy compounds in the presence of pyridine and lithium chloride. A model compound (3) was also prepared by the reaction of 2b with phenol, its synthesis permitting an optimization of polymerization conditions. Poly(ester‐imides) were fully characterized by FTIR, UV‐vis and NMR spectroscopy. Both biphenylene‐ and binaphthylene‐based poly(ester‐imide)s exhibited excellent solubility in common organic solvents such as tetrahydrofuran, m‐cresol, pyridine and dichloromethane. However, binaphthylene‐based poly(ester‐imide)s were more soluble than those of biphenylene‐based polymers in highly polar organic solvents, including N‐methyl‐2‐pyrrolidone, N,N‐dimethylacetamide, N,N‐dimethylformamide and dimethyl sulfoxide. From differential scanning calorimetry thermograms, the polymers showed glass‐transition temperatures between 261 and 315 °C. Thermal behaviour of the polymers obtained was characterized by thermogravimetric analysis, and the 10 % weight loss temperatures of the poly(ester‐imide)s was in the range 449–491 °C in nitrogen. Furthermore, crystallinity of the polymers was estimated by means of wide‐angle X‐ray diffraction. The resultant poly(ester‐imide)s exhibited nearly an amorphous nature, except poly(ester‐imide)s derived from hydroquinone and 4,4′‐dihydroxybiphenyl. In general, polymers containing binaphthyl units showed higher thermal stability but lower crystallinity than polymers containing biphenyl units. Copyright © 2005 Society of Chemical Industry     

Synthesis and characterization of polyamides and poly(amide‐imide)s derived from 2,6‐bis(3‐aminophenoxy)benzonitrile or 2,6‐bis(4‐aminophenoxy)benzonitrile

A series of polyamides and poly(amide‐imide)s was prepared by direct polycondensation of ether and nitrile group containing aromatic diamines with aromatic dicarboxylic acids and bis(carboxyphthalimide)s respectively in N‐methyl 2‐pyrrolidone (NMP) using triphenyl phosphite and pyridine as condensing agents. New diamines, such as 2,6‐bis(4‐aminophenoxy)benzonitrile and 2,6‐bis(3‐aminophenoxy)benzonitrile, were prepared from 2,6‐dichlorobenzonitrile with 4‐aminophenol and 3‐aminophenol, respectively, in NMP using potassium carbonate. Bis(carboxyphthalimide)s were prepared from the reaction of trimellitic anhydride with various aromatic diamines in N,N′‐dimethyl formamide. The inherent viscosities of the resulting polymers were in the range of 0.27 to 0.93 dl g^?1 in NMP and the glass transition temperatures were between 175 and 298 °C. All polymers were soluble in dipolar aprotic solvents such as dimethylsulfoxide, dimethylacetamide and NMP. All polymers were stable up to 350 °C with a char yield of above 40 % at 900 °C in nitrogen atmosphere. All polymers were found to be amorphous except the polyamide derived from isophthalic acid and the poly(amide‐imide)s derived from diaminodiphenylether and diaminobenzophenone based bis(carboxyphthalimide)s. Copyright © 2004 Society of Chemical Industry     

A comparison of triazole cross‐linked polymers based on poly‐AMMO and GAP: Mechanical properties and curing kinetics

Triazole cross‐linked polymers based on poly(3‐azidomethyl‐3‐methyl oxetane) (poly‐AMMO) and glycidyl azide polymer (GAP) were prepared using bis‐propargyl‐1,4‐cyclohexyl‐dicarboxylate (BPHA) as curing agent, respectively. Swelling tests demonstrated that cross‐linking densities of the resulted polymers both increased with the increase of BPHA. Triazole cross‐linked polymers based on poly‐AMMO showed superior tensile strength and elongation at break than those of GAP at comparable stoichiometry. The curing kinetics was also investigated by FTIR, and GAP exhibited faster reaction rate when reacted with BPHA than that of poly‐AMMO. In addition, with the increase of cross‐linking density, the glass transition temperature (T_g) of as‐prepared polymers significantly increased, and poly‐AMMO‐based polymers showed stronger T_g‐raising effect than GAP‐based polymers. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43341.     

Near‐infrared‐active and pH‐responsive fluorescent polymer‐integrated hybrid graphene oxide nanoparticles for the detection and treatment of cancer

Hybrid nanoparticles for theragnosis have great potentiality to bring desire functionalities in one integrated system. The development of bioimaging guided photothermal therapy (PTT) is pivotal in optimizing cytotoxic cancer therapy. We report near‐infrared (NIR)‐active and pH‐responsive fluorescent, catechol‐conjugated, reduced graphene oxide (rGO)‐anchored hybrid nanoparticles that can sharply increase the photothermal heat in response to NIR exposure and exhibit pH‐dependent fluorescence emission for the detection of tumor areas without causing cell toxicity. The optoelectronic absorption property of poly(3,4‐ethylenedioxythiophene) [PEDOT]:dopamine‐conjugated poly(4‐styrenesulfonate‐co‐maleic acid) [D‐PSM] and 3′,4′‐dihydroxyacetophenone/boron‐dipyrromethene [CCDP/BODIPY]‐quaternized polyethylene glycol grafted poly(dimethylaminoethyl methacrylate) (C/B‐PgP) present in this hybrid nanoparticles resulted in efficient photothermal conversion with pH‐tunable fluorescence that exerted sufficient photothermal cytotoxicity to cancer cells. The in vitro cellular uptake was measured by confocal laser scanning microscopy, allowing the therapeutic efficiency and bioimaging effects to be explored. We expect that the broad optical absorption property of PEDOT:D‐PSM with BODIPY‐conjugated polymers on rGO sheets would get tremendous attraction in this enormous rising PTT with cancer detectable biomarker. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43791.     

Synthesis and characterization of light‐absorbing cyclopentadithiophene‐based donor–acceptor copolymers

Cyclopentadithiophene and benzothiadiazole based donor–acceptor polymers are fast emerging as the most promising class of materials for organic solar cells. Here we report on a series of Cyclopentadithiophene and benzothiadiazole based conjugated polymers, namely poly[4,7‐bis(4,4‐dioctyl‐4H‐cyclopenta[2,1‐b;3,4‐b′]dithiophene‐2‐yl)benzo[1,2,5]thiadiazole] (P1), poly[4,7‐bis(4,4‐dioctyl‐4H‐cyclopenta[2,1‐b;3,4‐b′]dithiophene‐2‐yl)benzo[1,2,5]thiadiazole‐alt‐9‐(heptadecan‐9‐yl)‐2,7‐bis(4,4,5,5‐tetramethyl)‐1,3,2‐dioxaborolan‐2‐yl)‐9H‐carbazole] (P2) and poly[4,7‐bis(4,4‐dioctyl‐4H‐cyclopenta[2,1‐b;3,4‐b′]dithiophene‐2‐yl)benzo[1,2,5]thiadiazole‐alt‐5,11‐bis(2‐hexyldecyl)‐3,9‐bis(4,4,5,5‐tetramethyl)‐1,3,2‐dioxaborolan‐2‐yl)‐5,11‐dihydroindolo[3,2‐b]carbazole] (P3), with alternating donor and acceptor units and discuss their photophysical and electrochemical properties. Stille coupling of 2‐tributylstannyl‐4,4‐dioctylcyclopenta[2,1‐b:3,4‐b′]dithiophene with 4,7‐dibromobenzo[1,2,5]thiadiazole generated the alternating donor–acceptor monomer 4,7‐bis(4,4‐dioctyl‐4H‐cyclopenta[2,1‐b;3,4‐b′]dithiophene‐2‐yl)benzo[1,2,5]thiadiazole (CPDT‐BT‐CPDT). Homopolymer P1 of CPDT‐BT‐CPDT was synthesized by oxidative polymerization using FeCl₃. Copolymers P2 and P3 were synthesized by palladium‐catalysed Suzuki polycondensation. The synthesized polymers showed good solubility in common organic solvents, and UV‐visible measurements showed that the absorption maxima of the polymers lie in the range 624 to 670 nm. The energy gaps of these polymers were found to lie in the range 1.29 to 1.50 eV. Gel permeation chromatography measurements against polystyrene standards showed the number‐average molecular weight to be in the range (2.2–6.0) × 10⁴ g mol^?1. Thermogravimetric analysis showed the polymers to possess high thermal stability. A preliminary study of photodiode devices prepared using polymers P1, P2 and P3 when blended with the PC₇₁BM electron acceptor found that P2 is the optimum chemical structure for pursuing further device optimization.© 2015 Society of Chemical Industry     

Synthesis and characterization of new aromatic poly(amide–imide)s based on 4‐aryl‐2,6‐bis(4‐trimellitimidophenyl) pyridines

New diimide–dicarboxylic acids, ie 4‐phenyl‐2,6‐bis(4‐trimellitimidophenyl)pyridine and 4‐p‐biphenyl‐2,6‐bis‐(4‐trimellitimidophenyl)pyridine, were synthesized by the condensation reaction of 4‐phenyl‐2,6‐bis(4‐aminophenyl)pyridine and 4‐p‐biphenyl‐2,6‐bis(4‐aminophenyl)pyridine with trimellitic anhydride in glacial acetic acid or dimethylformamide. The monomers were fully characterized by FT‐IR and NMR spectroscopies, and elemental analyses. A series of novel poly(amide–imide)s with inherent viscosities of 0.68–0.87 dl g^?1 was prepared from the two diimide–diacids with various aromatic diamines by direct polycondensation. The poly(amide–imide)s were characterized by FT‐IR and NMR spectroscopies. The λ_max data for the resulting poly(amide–imide)s were in the range of 260–292 nm. These polymers exhibited good solubilities in polar aprotic solvents. The 10 % weight loss temperatures are above 485 °C under a nitrogen atmosphere. Copyright © 2004 Society of Chemical Industry     

Liquid crystalline and photocrosslinkable poly(4,4′‐stilbeneoxy) alkylarylphosphates

Three series of liquid crystalline and photocrosslinkable poly(4,4′‐stilbeneoxy) alkylarylphosphates were synthesized from various 4,4′‐bis(m‐hydroxyalkyloxy)stilbenes (m = 2, 4, 6, 8, 10) and arylphosphorodichloridates in chloroform by solution polycondensation method. Polarized optical microscope (POM) and differential scanning calorimetry (DSC) observations revealed that polymers containing less than four methylene spacer groups did not exhibit liquid crystalline (LC) texture, possibly due to smaller microdomain and restricted movement of the mesogen. In contrast, polymers containing more than four methylene spacer group established LC texture, which has been attributed to the larger monodomain and free movement of mesogens. Thermogravimetric analysis (TGA) data indicated that thermal stability and char yield decreased with increasing flexible methylene spacer groups, increased significantly for biphenyloxy and 1‐naphthyloxy containing polymers than that of phenyloxy containing polymers ascribed to increasing aromaticity, size, and number of aromatic rings. Photocrosslinking of stilbene containing polymers has been shown to proceed via 2π‐2π cycloaddition reaction by Ultra‐violet (UV) and fluorescence. The rate photocrosslinking has been found to increase with increasing number of methylene group in the main chain. The aromaticity of the side chain also increases the rate of crosslinking. POLYM. ENG. SCI., 2012. © 2011 Society of Plastics Engineers     

Synthesis and characterization of organo‐soluble poly(ether ether ketone)s and poly(ether ether ketone ketone)s containing pendant pentadecyl chains

Poly(ether ether ketone)s and poly(ether ether ketone ketone)s containing pendant pentadecyl chains were synthesized by polycondensation of each of the two bisphenol monomers viz, 1,1,1‐[bis(4‐hydroxyphenyl)‐4′‐pentadecylphenyl]ethane and 1,1‐bis(4‐hydroxyphenyl)‐3‐pentadecyl cyclohexane with activated aromatic dihalides namely, 4,4′‐difluorobenzophenone, and 1,3‐bis(4‐fluorobenzoyl)benzene in a solvent mixture of N,N‐dimethylacetamide and toluene, in the presence of anhydrous potassium carbonate. Polymers were isolated as white fibrous materials with inherent viscosities and number average molecular weights in the range 0.70–1.27 dL g^?1 and 76,620–1,36,720, respectively. Poly(ether ether ketone)s and poly(ether ether ketone ketone)s were found to be soluble at room temperature in organic solvents such as chloroform, dichloromethane, tetrahydrofuran, and pyridine and could be cast into tough, transparent, and flexible films from their solutions in chloroform. Wide angle X‐ray diffraction patterns exhibited a broad halo at around 2θ = ～ 19° indicating that the polymers containing pentadecyl chains were amorphous in nature. In the small‐angle region, diffuse reflections of a typically layered structures resulting from the packing of pentadecyl side chains were observed. The temperature at 10% weight loss, obtained from TG curves, for poly(ether ether ketone)s and poly(ether ether ketone ketone)s were in the range 416–459°C, indicating their good thermal stability. A substantial drop in glass transition temperatures (68–78°C) was observed for poly(ether ether ketone)s and poly(ether ether ketone ketone)s due to “internal plasticization” effect of flexible pendant pentadecyl chains. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Synthesis and properties of new aromatic poly(ester‐imide)s derived from 4‐p‐biphenyl‐2,6‐bis(4‐trimellitimidophenyl) pyridine and various dihydroxy compounds

A novel class of wholly aromatic poly(ester‐imide)s, having a biphenylene pendant group, with inherent viscosities of 0.32–0.49 dL g^?1 was prepared by the diphenylchlorophosphate‐activated direct polyesterification of the preformed imide‐ring‐containing diacid, 4‐p‐biphenyl‐2,6‐bis(4‐trimellitimidophenyl)pyridine (1) with various aromatic dihydroxy compounds in the presence of pyridine and lithium chloride. A reference diacid, 2,6‐bis(trimellitimido)pyridine (2) without a biphenylene pendant group and two phenylene rings in the backbone, was also synthesized for comparison purposes. At first, with due attention to structural similarity and to compare the characterization data, a model compound (3) was synthesized by the reaction of compound 1 with two mole equivalents of phenol. Moreover, the optimum condition of polymerization reactions was obtained via a study of the model compound synthesis. All of the resulting polymers were characterized by Fourier transform infrared and ¹H NMR spectroscopy and elemental analysis. The ultraviolet λ_max values of the poly(ester‐imide)s were also determined. All of the resulting polymers exhibited excellent solubility in common organic solvents, such as pyridine, chloroform, tetrahydrofuran, and m‐cresol, as well as in polar organic solvents, such as N‐methyl‐2‐pyrrolidone, N,N‐dimethylacetamide, N,N‐dimethylformamide, and dimethyl sulfoxide. The crystalline nature of the polymers obtained was evaluated by means of wide‐angle X‐ray diffraction. The resulting poly(ester‐imide)s showed nearly an amorphous nature, except poly(ester‐imide) derived from 4,4′‐dihydroxy biphenyl. The glass transition temperatures (T_g) of the polymers determined by differential scanning calorimetry thermograms were in the range 298–342 °C. The 10% weight loss temperatures (T_10%) from thermogravimetric analysis curves were found to be in the range 433–471 °C in nitrogen. Films of the polymers were also prepared by casting the solutions. Copyright © 2006 Society of Chemical Industry     

Microwave‐assisted and classical heating polycondensation reaction of bis(p‐amido benzoic acid)‐N‐trimellitylimido‐L‐leucine with diisocyanates as a new method for preparation of optically active poly(amide imide)s

A new class of optically active poly(amide imide)s were synthesized via direct polycondensation reaction of diisocyanates with a chiral diacid monomer. The step‐growth polymerization reactions of monomer bis(p‐amido benzoic acid)‐N‐trimellitylimido‐L‐leucine (BPABTL) (5) as a diacid monomer with 4,4′‐methylene bis(4‐phenylisocyanate) (MDI) (6) was performed under microwave irradiation, solution polymerization under gradual heating and reflux condition in the presence of pyridine (Py), dibuthyltin dilurate (DBTDL), and triethylamine (TEA) as a catalyst and without a catalyst, respectively. The optimized polymerization conditions according to solvent and catalyst for each method were performed with tolylene‐2,4‐diisocyanate (TDI) (7), hexamethylene diisocyanate (HDI) (8), and isophorone diisocyanate (IPDI) (9) to produce optically active poly(amide imide)s by the diisocyanate route. The resulting polymers have inherent viscosities in the range of 0.09–1.10 dL/g. These polymers are optically active, thermally stable, and soluble in amide type solvents. All of the above polymers were fully characterized by IR spectroscopy, ¹H NMR spectroscopy, elemental analyses, specific rotation, and thermal analyses methods. Some structural characterization and physical properties of this new optically active poly(amide imide)s are reported. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 1647–1659, 2004