Low-bandgap poly(4H-cyclopenta[def]phenanthrene) derivatives with 4,7-dithienyl-2,1,3-benzothiadiazole unit for photovoltaic cells

A series of conjugated polymer bearing 4H-cyclopenta[def]phenanthrene (CPP) unit have been synthesized and was evaluated in bulk heterojunction solar cell. The alternating copolymers with CPP unit were incorporated with 4,7-dithienyl-2,1,3-benzothiadiazole (DTBT) unit by Suzuki conditions. The newly synthesized copolymers, poly(2,6-((4,4-bis(2-ethylhexyl)-4H-cyclopenta[def]phenanthrene))-alt-(4,7-((2-thienyl)-2,1,3-benzothiadiazole))) (PCPP-DTBT), and poly(2,6-(4,4-bis(4-((2-ethylhexyl)oxy)phenyl)-4H-cyclopenta[def]phenanthrene)-alt-(4,7-((2-thienyl)-2,1,3-benzothiadiazole))) (PBEHPCPP-DTBT), contain dialkyl and bis(alkoxyphenyl) groups in the CPP unit, respectively. The HOMO-LUMO energy bandgaps of these materials, estimated from UV-vis spectroscopy and cyclic voltammetry (CV), were 2.00 eV for PCPP-DTBT and 1.80 eV for PBEHPCPP-DTBT. Bulk heterojunction solar cells based on the blends of the polymers with [6,6]phenyl-C₇₁-butyric acid methyl ester (PC₇₁BM) gave power conversion efficiencies as 1.00% for PCPP-DTBT and 1.12% for PBEHPCPP-DTBT under AM 1.5, 100 mW/cm².     

Synthesis of conjugated polymers with broad absorption bands and photovoltaic properties as bulk heterojuction solar cells

Two new broad absorbing alternating copolymers, poly[1-(2,6-diisopropylphenyl)-2,5-bis(2-thienyl)pyrrole-alt-4,7-bis(3-octyl-2-thienyl)benzothiadiazole] (PTPTTBT-P1) and poly[1-(p-octylphenyl)-2,5-bis(2-thienyl)pyrrole-alt-4,7-bis(3-octyl-2-thienyl)benzothiadiazole] (PTPTTBT-P2), were prepared via Suzuki polycondensation with high yields. The two polymers were found to show characteristic absorption in the visible region of the solar spectrum. Interestingly the absorption of PTPTTBT-P1 was found to cover the visible region from 350 to 650 nm with the broad and flat absorption maximum from 440 to 510 nm in film and the absorption of PTPTTBT-P2 was found to cover the visible region from 350 to 950 nm with the relatively distinct absorption maxima at 425 and 522 nm and very weak absorption maximum at 832 nm in film. The electrochemical band gaps of the polymers were calculated to be 1.88 eV and 1.87 eV, respectively, while the optical band gaps of the polymers were calculated to be 1.94 eV and 1.87 eV, respectively. The photovoltaic properties of polymers were investigated with bulk heterojunction (BHJ) solar cells fabricated in ITO/PEDOT:PSS/polymer:PC₇₀BM(1:5 wt%)/TiOx/Al configurations. The maximum power conversion efficiency (PCE) of the solar cell composed of PTPTTBT-P1:PC₇₀BM as an active layer was 1.57% with current density (J_sc) of 8.17 mA/cm², open circuit voltage (V_oc) of 0.52 V and fill factor (FF) of 36%.     

Synthesis and characterization of fluorine–thiophene-based π-conjugated polymers using coupling reaction

A solution processible fluorine–thiophene-based copolymers, namely poly[2,7-bis(4-octyl-2-thienyl)-9,9-dioctylfluorene-co-alt-5,5′-(2,2′-bithiophene)] (P1), poly[2,7-bis(3-octyl-2-thienyl)-9,9-dioctylfluorene-co-alt-5,5′-(2,2′-bithiophene)] (P2), poly[2,7-bis(3,3′-dioctyl-5,5′-bithien-2yl)-9,9′-dioctylfluorene-co-alt-5,5′-(2,2′-bithiophene)] (P3) were synthesized using Suzuki and Stille coupling reaction. The polymers showed weight loss starting around 400 °C indicative of good thermal stability. UV–vis properties and photoluminescence (PL) properties were investigated in toluene. P1, P2 and P3 exhibited the absorption maximum at 450, 428 and 435 nm and their PL spectrum peaked at 587, 559 and 560 nm, respectively. And all polymers, P1, P2 and P3, showed electroluminescence (EL) spectrum peaked at 592, 595 and 607 nm in the range of orange red. The polymers were electrochemically active in oxidation regions. P3 especially showed high oxidation stabilities in 1.17 V vs. Ag/Ag⁺. And P1 and P3 showed higher crystallinity than P2, because they have a repeated unit of 3,3-dialkyl-quaterthiophene.     

White Electroluminescence from a Single-Polymer System with Simultaneous Three-color Emission

A series of polymers were synthesized by incorporating low contents of fluorenone (FO) and 4,7-bis(2-thienyl)-2,1,3-benzothiadiazole (DBT) into the main chain of poly(9,9-dioctylfluorene). White-light emission was obtained from a single polymer by adjusting the FO and DBT contents. All polymers showed good thermal stability with 5% weight loss up to 410 °C and good solubility in common organic solvents. Electroluminescence devices with indium tin oxide/poly(3,4-ethylenedioxythiophene): poly(styrenesulfonate)/emission layer/Ca/Al structure were found to emit white light with Commission Internationale de l’Eclairage coordinate of (0.37, 0.34). These devices exhibited a maxium brightness of 3414 cd/m² and a maximum current efficiency of 2.79 cd/A.     

Synthesis and properties of cyclopentadithiophene-based poly(silarylenesiloxane) derivatives

Poly(silarylenesiloxane) derivatives with 4,4-dimethylcyclopenta[2,1-b:3,4-b′]dithiophene moiety, bearing dimethyl- (P1), methylphenyl- (P2) and diphenyl- (P3) substituents on silyl moieties, were prepared via polycondensation of the corresponding disilanol monomers, that is, 2,6-bis(dimethylhydroxysilyl)-4,4-dimethylcyclopenta[2,1-b:3,4-b′]dithiophene (M1), 2,6-bis(methylphenylhydroxysilyl)-4,4-dimethylcyclopenta[2,1-b:3,4-b′]dithiophene (M2), and 2,6-bis(diphenylhydroxysilyl)-4,4-dimethylcyclopenta[2,1-b:3,4-b′]dithiophene (M3), respectively. P1-P3 exhibited the good solubility in common organic solvents, such as benzene, toluene, chloroform, dichloromethane, THF, and so on. The glass transition temperatures (T_gs) of P1, P2 and P3 were determined by differential scanning calorimetry to be 56, 97 and 137 °C, respectively, depending on the substituent on the silyl moieties. No melting temperatures (T_ms) of P1, P2 and P3 were observed, suggesting the obtained P1-P3 are amorphous polymers. The temperatures at 5% weight loss (T_d5s) of P1, P2 and P3 were 460, 459 and 479 °C, respectively, indicating that the larger number of phenyl group on the silyl moieties resulted in the better thermostability. Bathochromic and hyperchromic effects were observed in the absorption and fluorescence spectra by introducing silyl substituents onto 4,4-dimethylcyclopenta[2,1-b:3,4-b′]dithiophene moiety. In addition, the bathochromic shift of the maximum absorption (λ_abs) and the increase in the fluorescence quantum yield (Φ_F) were observed by the introduction of phenyl group onto the silyl moieties.     

Effects of internal linkage groups of fluorinated diamine on the optical and dielectric properties of polyimide thin films

To investigate the difference of the trifluoromethyl (CF₃) group and ether group affecting the optical property of fluorinated polyimides (PIs), we prepared 4,4′-bis(4-amino-2-trifluoromethylphenoxy)diphenyl ether (4) with three ether groups and 2,2-bis[4-(4-amino-2-trifluoromethylphenoxy)phenyl]hexafluoropropane (5) with four CF₃ groups with 2-chloro-5-nitrobenzotrifluoride and 4,4′-dihydroxydiphenyl ether or 2,2-bis(4-hydroxyphenol)hexafluoropropane. Two series of organosoluble and light-colored PIs (4a-4c, 5a-5c) were synthesized from 4 and 5 with various aromatic dianhydrides: 3,3,4,4-benzophenonetetracarboxylic dianhydride (BTDA) (a), 4,4-oxydiphthalic anhydride (ODPA) (b), and 4,4-hexafluoroisopropylidenediphthalic anhydride (6FDA) (c), prepared through a typical two-step polymerization method. These PIs were soluble in amide polar solvents and even in less polar solvents. The glass-transition temperatures (T_g) of 4a-5c were 221-249 °C and the 10% weight-loss temperatures were above 530 °C. Their films had cutoff wavelengths between 339 and 399 nm and yellowness index ranges from 1.95 to 42.60. The dielectric constants estimated from the average refractive indices are 2.59-2.93 (1 MHz). In a comparison of the PI series based on 4, 5, and 4,4′-bis(4-amino-2-trifluoromethylphenoxy)biphenyl (6), we found that the CF₃ group and ether group on the diamine had almost same effect in lowering the color, but the ether group had better thermal stability. The color intensity of the three PI series was lowered in the following order: 6 > 4 > 5. The PI 5c, synthesized from diamine 5 and dianhydride c, had six CF₃ groups in a repeated segment and ether group at the same time, so it exhibited the lightest color among the three series.     

Copoly(1,3,4-oxadiazole-ether)s containing phthalide groups and thin films made therefrom

A series of aromatic copolyethers containing 1,3,4-oxadiazole rings and phthalide groups was prepared by nucleophilic substitution polymerization technique of phenolphthalein, 1, or of an equimolecular amount of 1 and different bisphenols 2, such as: 4,4′-isopropylidenediphenol, 4,4′-(hexafluoroisopropylidene)diphenol, 4,4′-(1,4-phenylene-diisopropylidene)bisphenol, 4,4′-cyclohexylidene-bisphenol and 2,7-dihydroxynaphthalene, with 2,5-bis(p-fluorophenyl)-1,3,4-oxadiazole, 3. The polymers were easily soluble in polar solvents such as N-methylpyrrolidone, N,N-dimethylacetamide, N,N-dimethylformamide and chloroform and can be cast from solutions into thin flexible films. They showed high thermal stability, with decomposition temperature being above 400 °C. The polymers exhibited a glass transition temperature in the range of 220-271 °C, with reasonable interval between glass transition and decomposition temperature. Electrical insulating properties of some polymer films were evaluated on the basis of dielectric constant and dielectric loss and their variation with frequency and temperature. The values of the dielectric constant at 10 kHz and 20 °C were in the range of 2.98-3.15.     

Cross-linkable highly halogenated poly(arylene ether ketone/sulfone)s with tunable refractive index: Synthesis, characterization and optical properties

A series of novel cross-linkable, highly halogenated poly(arylene ether ketone)s (HPAEKs) and poly(arylene ether sulfone)s (HPAESs) with different bromine contents have been designed and prepared by polycondensation reactions for use as optical waveguide materials. The method used for their preparation involved reacting decafluorodiphenyl ketone/sulfone (DFPK/DFPS) with a mixture of 4,4′-isopropylidene bis(2,6-dibromophenol) (4Br-BPA), 4,4′-(hexafluoroisopropylidene)diphenol (6F-BPA), and 1,1-bis(4-hydroxyphenyl)ethyl-1-phenyl-2,3,5,6-tetrafluorostyrol ether (BHPFS). The feed ratio of 4Br-BPA to the total bisphenols varied from 0 to 80 mol.%, while that of BHPFS remained at 20% for all polymers. The resulting polymers have excellent solubility in most common organic solvents such as tetrahydrofuran, cyclohexanone and N,N-dimethylacetamide (DMAc) and can be easily cast into optical-quality thin films. A high glass transition temperature in the range of 164-206 °C was found for these polymers, which could be further increased by about 20 °C upon thermal or photochemical cross-linking. Slab and channel waveguides have been prepared from these polymers. All of them exhibited low optical loss (0.4-0.6 dB/cm) at the telecommunication wavelength of 1550 nm. Due to the relatively higher polarizability of the C-Br bond than that of the C-H bond, an increase in the refractive index was observed as the bromine content in the polymers increased. Consequently, the refractive index of HPAEKs and HPAESs can be readily adjusted within a wide range from 1.51 to 1.57 by simply changing the ratio of the bromine-containing bisphenol in the feed. This variability, along with the excellent cross-linking capability, allows these polymers to be used as both the core and the cladding materials for the waveguide device fabrication and provides a greater flexibility in the design of device structures.     

A highly selective and sensitive fluorescence chemosensor based on optically active polybinaphthyls for Hg

The chiral polymer was synthesized by the polymerization of 4,7-diethynylbenzo[2,1,3]-thiadiazole (M-1) with (R)-6,6′-dibutyl-3,3′-diiodo-2,2′-bis(diethylaminoethoxy)-1,1′-binaphthyl (R-M-1) via Pd-catalyzed Sonogashira reaction. The chiral polymer has orange fluorescence due to the extended π-electronic structure between binaphthyl unit and benzo[2,1,3]thiadiazole (BT) group via ethynyl bridge. The responsive optical properties of the polymer on various metal ions were investigated by fluorescence spectra. The fluorescence of the chiral polymer can produce the pronounced enhancement as high as 1.8-fold upon addition of 1:2 molar ratio of Hg²⁺. Compared with other cations, such as K⁺, Mg²⁺, Pb²⁺, Co²⁺, Ni²⁺, Ag⁺, Cd²⁺, Cu²⁺, Zn²⁺, Mn²⁺ and Fe³⁺, Hg²⁺ can produce the pronounced fluorescence response of the polymer. The result indicates this kind of chiral polybinaphthyls incorporating diethylamino and benzo[2,1,3]thiadiazole (BT) moieties as receptors exhibits highly sensitive and selective behavior for Hg²⁺ detection.     

Synthesis and properties of various PPV derivatives with phenyl substituents

New electroluminescent polymers with various phenyl groups, poly[2-dimethyl(octyl)silyl-5-(4-(dimethyl(octyl)silyl)phenyl)-1,4-phenylenevinylene] (P1), poly[2,5-bis(4-(dimethyl(octyl)silyl)phenyl)-1,4-phenylenevinylene] (P2), poly[2,5-bis(9,9-dihexylfluorenyl)-1,4-phenylenevinylene] (P3), and poly[2,5-bis(4-(4-(2-etylhexyloxy)phenyl)phenyl)-1,4-phenylenevinylene] (P4), have been synthesized by the Gilch polymerization. The maximum absorption peaks of P1-P4 appeared at 388-423 nm in THF solution, and are red-shifted to 404-425 nm in solid thin film. The photoluminescence (PL) emission spectra of P1-P4 show a maximum peak at 482-503 nm in THF solution and at 521-549 nm as the solid film state. The emission spectra in the solid film state are more red-shifted over 40 nm, and the full width at half maximum (fwhm) was 30 nm greater than the solution conditions. The polymer light-emitting diodes (PLEDs) with the configuration of ITO/PEDOT/polymer/Al emitted light with maximum peaks at around 517-546 nm. The various phenyl substituents, with intermolecular interactions in the solid film state, can introduce the color tuning and device performance enhancement of the conjugated polymer as an emissive layer in PLED.     

Polybinaphthyls incorporating chiral 2,2′-binaphthyl and isoquinoline moieties by Sonogashira reaction

Polymers P-1, P-2, P-3, P-4 and P-5 were synthesized by the polymerization of 5,8-bis(ethynyl)isoquinoline (M-1) with (R)-3,3′-diiodo-2,2′-bisbutoxy-1,1′-binaphthyl ((R)-M-2), (S)-3,3′-diiodo-2,2′-bisbutoxy-1,1′-binaphthyl ((S)-M-2), (R)-6,6′-dibromo-2,2′-bisbutoxy-1,1′-binaphthyl ((R)-M-3), (S)-6,6′-dibromo-2,2′-bisbutoxy-1,1′-binaphthyl ((S)-M-3), and rac-6,6′-dibromo-2,2′-bisbutoxy-1,1′-binaphthyl (M-4) under Sonogashira reaction, respectively. Both monomers and polymers were analyzed by NMR, MS, FT-IR, UV-vis spectroscopy, DSC-TGA, fluorescence spectroscopy, GPC and circular dichroism (CD) spectroscopy. CD spectra of polymers P-1 and P-2, P-3 and P-4 are almost identical except that they gave opposite signals at each wavelength. The long wavelength CD effect of P-1 and P-2 can be regarded as the more extended conjugated structure in the repeating unit and the helical backbone in the polymer chain. All five polymers have strong blue-green fluorescence due to the efficient energy migration from the extended π-electronic structure of the repeating unit of the polymers to the chiral binaphthyl core and are expected to provide understanding of structure-property relationships of the chiral conjugated polymers.     

Preparation of π-conjugated polymers consisting of 2-decylbenzimidazole and thiophene units and chemical properties of the polymers

Polycondensation by Stille coupling of 2-decyl-4,7-dibromobenzimidazoles and N-methyl-2-decyl-4,7-dibromobenzimidazole with 2,5-bis(trimethylstannyl)thiophene and 5,5′-bis(trimethylstannyl)-2,2′-bithiophene gave the corresponding π-conjugated polymers, poly(2-decylbenzimidazole-4,7-diyl-thiophene-2,5-diyl) 1b, poly(2-decylbenzimidazole-4,7-diyl-bithiophene-2,5-diyl) 1c and poly(N-methyl-2-decylbenzimidazole-4,7-diyl-thiophene-2,5-diyl) 2b, in 98-99% yields. The polymers 1b and 2b were fully soluble in CF₃COOH, and partially soluble in DMF (about 60 and 40% for 1b and 2b, respectively) and NMP (about 70 and 40%, respectively). The NMP soluble part of 1b and DMF soluble part of 2b gave values of 0.36 and 0.24 dl g⁻¹ in NMP and DMF, respectively. The DMF soluble part of 1b, 1c and 2b showed absorption peaks at about 458, 465 and 388 nm, respectively, in DMF. In an alkaline medium the absorption peaks of 1b and 1c are shifted to a longer wavelength by 92-101 nm; the observed shifts in the acidic medium and alkaline medium were much larger than those observed with usual benzimidazoles with low molecular weights. Packing structures of 1b, 1c and 2b are discussed based on their XRD patterns.     

Synthesis of terminal Si-H irregular tetra-branched star polysiloxanes. Pt-catalyzed hydrosilylation with unsaturated epoxides. Polysiloxane films by photo-acid catalyzed crosslinking

Acid catalyzed insertion of octamethylcyclotetrasiloxane (D₄) into the Si-O bonds of tetrakis(dimethylsiloxy)silane leads to irregular tetra-branched star polymers—tetrakis(ω-dimethylsiloxy)poly(dimethylsiloxy)silane (I). The terminal Si-H bonds of I have been modified by Pt-catalyzed hydrosilylation with 4-vinylcyclohexane-1,2-epoxide to yield a tetra-branched star polydimethylsiloxanes (PDMS) with terminal 2′-ethyl-4-cyclohexanyl-1,2-epoxide groups (II). Solutions of this material and a catalytic amounts of diaryl iodonium hexafluoroantimonate, a photo-acid catalyst, were cast onto glass slides and subsequently irradiated. This results in formation of crosslinked PDMS films (V). The soluble tetra-branched PDMS stars have been characterized by ¹H, ¹³C, and ²⁹Si NMR as well as by IR spectroscopy. Their molecular weight distributions have been determined by gel permeation chromatography (GPC), multi-angle laser light scattering (MALLS), and end groups analysis. Their viscosities were measured with a Brookfield viscometer. The thermal stability of the polymers and the crosslinked films were determined by TGA. The glass transition temperatures (T_g)s of the polymers were determined by DSC. The loss (G″) and storage (G′) shear moduli of the films were determined by DMTA. Surface properties of the films were determined by measurement of static contact angles.Similar star polymers, tetrakis(dimethylsiloxy)poly[3′,3′,3′-trifluoropropylmethylsiloxyl]silanes (III) were prepared by acid catalyzed equilibration of tetrakis(dimethylsiloxy)silane with 1,3,5-trimethyl-1,3,5-tris(3′,3′,3′-trifluoropropyl)cyclotrisiloxanes (D₃^F). These were, likewise, modified by Pt-catalyzed hydrosilylation with 4-vinylcyclohexane-1,2-epoxide. Films (VI) of this material were similarly prepared by photo-acid catalyzed crosslinking.     

Tyrosine-based poly(m-phenyleneethynylene-p-phenyleneethynylene)s. Helix folding and responsiveness to a base

The Sonogashira-Hagihara polymerization of 3′,5′-diiodo-N-α-tert-butoxycarbonyl-l-tyrosine methyl ester (1) and 3′,5′-diiodo-N-α-tert-butoxycarbonyl-O-methyl-l-tyrosine methyl ester (2) with para-diethynylbenzene (3) was carried out to obtain optically active poly(m-phenyleneethynylene-p-phenyleneethynylene)s [poly(1) and poly(2)] with M_n’s ranging from 9900 to 15,000 in 80-87% yields. Poly(1) exhibited intense CD signals in DMSO and THF, but did not in CH₂Cl₂, indicating that it took a predominantly one-handed helical conformation in the former two solvents. On the other hand, there was no evidence for poly(2) to take a helical structure in these solvents. Poly(1) turned the CD sign at 390 nm from plus to minus in DMSO/H₂O = 9/1 (v/v) by the addition of NaOH. Alkaline hydrolysis of ester moieties of poly(1) and poly(2) gave the corresponding polymers having carboxy groups [poly(1a) and poly(2a)]. Poly(1a) and poly(2a) increased the CD intensity by the addition of NaOH.     

Synthesis and properties of ornithine- and lysine-based poly(N-propargylamides). Responsiveness of the helical structure to acids

Ornithine- and lysine-based novel N-propargylamides, N-α-tert-butoxycarbonyl-N-δ-fluorenylmethoxycarbonyl-l-ornithine-N′-propargylamide (1), N-α-tert-butoxycarbonyl-N-?-fluorenylmethoxycarbonyl-l-lysine-N′-propargylamide (2), N-α-fluorenylmethoxycarbonyl-N-δ-tert-butoxycarbonyl-l-ornithine-N′-propargylamide (3), and N-α-fluorenylmethoxycarbonyl-N-?-tert-butoxycarbonyl-l-lysine-N′-propargylamide (4) were synthesized and polymerized with a rhodium catalyst. Polymers with moderate molecular weights were obtained in good yields. Poly(1)-poly(4) showed strong Cotton effects in THF, whose sign and wavelength depended on the substituents. They were satisfactorily converted into the corresponding polymers [poly(1a)-poly(4a)] with free amino groups. Poly(1a) and poly(2a) also formed a helix, while poly(3a) and poly(4a) did not. Poly(1a) and poly(2a) decreased the CD intensity by the addition of m- and o-phthalic acids.     

Synthesis and properties of polyacetylenes having pendent phenylethynylcarbazolyl groups

Novel acetylene monomers substituted with phenylethynylcarbazolyl groups, 3-[(4-octylphenyl)ethynyl]-9-propargylcarbazole (1), 3,6-bis[(4-octylphenyl)ethynyl]-9-propargylcarbazole (2), 9-(4-ethynylphenyl)-3-[(4-octylphenyl)ethynyl]carbazole (3), and 9-(4-ethynylphenyl)-3,6-bis[(4-octylphenyl)ethynyl]carbazole (4) were synthesized, and polymerized with Rh⁺(nbd)[η⁶-C₆H₅B⁻(C₆H₅)₃] and WCl₆-n-Bu₄Sn catalysts. The corresponding polyacetylenes with number-average molecular weights ranging from 9200 to 94?000 were obtained in 20-98% yields. The IR spectra of the polymers revealed that acetylene polymerization took place at the terminal ethynyl group, while the ethynylene group remained intact. The UV-vis absorption band edge wavelengths of W-based poly(3) and poly(4) were longer than those of the other polymers. W-Based poly(4) emitted fluorescence with the highest quantum yield (41%). Poly(1) exhibited excimer-based fluorescence in dilute solution.     

Synthesis of 1,9-bis[glycidyloxypropyl]penta(1′H,1′H,2′H,2′H-perfluoroalkylmethylsiloxane)s and copolymerization with piperazine

A series of 1,9-bis[glycidyloxypropyl]pentasiloxanes (IV-VI) were prepared by the platinum catalyzed hydrosilylation of 1,9-dihydridodecamethylpentasiloxane (I), 1,9-dihydrido-3,5,7-tris(3′,3′,3′-trifluoropropyl)heptamethylpentasiloxane (II), and 1,9-dihydrido-3,5,7-tris(1′H,1′H,2′H,2′H-perfluorooctyl)heptamethylpentasiloxane (III) with allyl glycidyl ether. Subsequently, IV-VI were copolymerized with piperazine to form high molecular weight copoly(carbosiloxane)s (VII-IX). The structures of the 1,9-bis[glycidyloxypropyl]penta-siloxanes (IV-VI) and copoly(carbosiloxane)s (VII-IX) were determined by ¹H, ¹³C, ²⁹Si, and ¹⁹F NMR as well as IR spectroscopy. The molecular weight distributions (M_w/M_n) of VII-IX have been characterized by gel permeation chromatography and their thermal properties measured by differential scanning calorimetry and thermal gravimetric analysis.     

Polybinaphthyls incorporating chiral (R) or (S)-2,2′-binaphthyland oxadiazole moieties by Stille reaction

Chiral polymers P-1 and P-2 were prepared by the polymerization of (R)-3,3′-diiodo-2,2′-bisbutoxy-1,1′-binaphthyl ((R)-M-1) and (S)-3,3′-diiodo-2,2′-bisbutoxy-1,1′-binaphthyl ((S)-M-1) with 2,5-bis[(4-tributylstannyl)phenyl]-1,3,4-oxadiazole (M-2) via Pd(PPh₃)₄ catalyzed Stille coupling reaction. 1,3,4-Oxadiazole unit not only has high electron affinity, high thermal and oxidative stability, but also serves as a good chromophore. Polymers have strong blue fluorescence due to the efficient energy migration from the extended π-electronic structure of the polymers to the chiral binaphthyl core and can be expected to have potential application in the materials of fluorescent sensors. Circular dichroism (CD) spectra of polymers P-1 and P-2 are almost identical except that they gave opposite signals at each wavelength. The long wavelengths CD effect of P-1 and P-2 can be regarded as the more extended conjugated structure in the repeating unit and a high rigidity of the polymer backbone.     

Direct synthesis of soluble and thermally stable poly(urethane-imide)s from a new triimide-dicarbonylazide

A new aromatic dicarbonylazide (3) bearing three preformed imide rings was synthesized by treating N-[3,5-bis(trimellitimido)phenyl]phthalimide (1) with thionyl chloride followed by a nucleophilic reaction with sodium azide. A novel family of fully aromatic poly(urethane-imide)s with inherent viscosities of 0.19-0.24 dl g⁻¹ were prepared from triimide-dicarbonylazide 3 and various aromatic diols. The polyaddition reactions readily proceeded in desirable yields as one-pot reactions starting from 3 without separately synthesis of the corresponding diisocyanate. All of the resulted polymers were thoroughly characterized by spectroscopic methods and elemental analyses. The poly(urethane-imide)s exhibited an excellent solubility in a variety of polar solvents. Crystallinity nature of the polymers was estimated by means of WXRD. The glass transition temperatures of the polymers determined by DSC method were in the range of 197-219 °C. The 10% weight loss temperatures of the poly(urethane-imide)s from their TGA/DTG curves were found to be in the range of 391-412 °C in nitrogen. The films of the polymers were also prepared by casting the solution.     

Amine groups-functionalized alcohol-soluble polyfluorene derivatives: Synthesis, photophysical properties, and self-assembly behaviors

A polyfluorene derivative with primary amine groups on side chains, poly(9,9-bis(6′-aminohexyl)fluorene) (PF-NH₂), was prepared through de-protection of its analogue polymer poly(9,9-bis(6′-butoxylcarbonylaminohexyl)fluorene) (PF-BOC) with hydrochloric acid followed by neutralizing the salt form of poly(6,6′-(9H-fluorene-9,9-diyl)dihexan-1-aminium chloride) (PF-NION). PF-NION had good solubility in methanol, DMSO, and DMF. Scanning electron microscopic images of PF-NH₂ in thin films revealed that intramolecular/intermolecular hydrogen bonding and π-π stacking interactions probably played an important role in the formation of special surface morphologies, which might be beneficial to the molecular ordering and device fabrication. The electroluminescence property of PF-NION was recorded on a simple polymer light-emitting diode (PLED) device configuration of ITO/PEDOT/Polymer/Al. Pure blue electroluminescence is achieved from double-layer PLEDs based on PF-NION as the active material with the CIE of (0.16, 0.08).