Design,synthesis, photophysical,and electrochemical properties of DCM‐based conjugated polymers for light‐emitting devices

A series of conjugated hyperbranched polymers, hyperbranched copolymers, and linear polymers containing 2‐pyran‐4‐ylidenemalononitrile (acceptor) and triphenylamine/fluorene (donor) units were synthesized and characterized by FTIR, ¹H NMR, thermogravimetric analyses, differential scanning calorimetry, gel permeation chromatography, UV–visible, photoluminescence, and cyclic voltammetry measurements. All the polymers show red‐light emission in the range of 566–656 nm both in solution and in solid state. The quantum efficiency of the polymers was in the range of 56–82%. Among the six polymers synthesized, only polymers containing fluorene units show T_g and polymers based on triphenylamine not exhibit T_g. The band gap of these polymers were found to be reasonably low; hyperbranched copolymer containing fluorene unit shows lowest band gap of 2.18 eV due to the stabilization of LUMO energy level by the electron withdrawing ? CN groups. The thermal and solubility behavior of the polymers were found to be good. All the EL spectra of the devices (indium‐tin oxide/poly(3,4‐ethylenedioxythiophene):poly(styrenesulfonate)/polymer/2,9‐dimethyl‐4,7‐diphenyl‐1,10‐phenanthroline/tris(8‐hydroxyquinoline)aluminum)/LiF/Al) show red‐light emission, and the device fabricated with P3 and P4 shows maximum luminance and luminous efficiency of 4104 cd m^?2 and 0.55 cd Å^?1 and 3696 cd m^?2 and 0.47 cd Å^?1, respectively, indicates that they had the best carrier balance. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012     

Development of solution‐dispersible hyperbranched conjugated polymer nanoparticles for Fe3+ fluorescent detection and their application in logic gate

Solution‐dispersible hyperbranched conjugated polymer nanoparticles (FT‐HBCPNs) consist of an intrinsic crosslinked rigid skeleton structure of both 9,9‐dihexyl‐fluorene and triphenylamine repeating units, and are synthesized via the miniemulsion Suzuki polymerization, and FT‐HBCPNs for highly selective and sensitive Fe³⁺ fluorescent detection and their application in logic gate at molecular level are successfully developed. FT‐HBCPNs with an average particle size of 10.6 nm can disperse in common organic solvents. FT‐HBCPNs show high selectivity and sensitivity for Fe³⁺ over other commonly co‐existent metal ions in THF solution with a detection limit of 3.65 × 10^?8 mol L^?1. Furthermore, homogeneous transparent thin films of FT‐HBCPNs developed by a simple spin‐coating method can be reversibly quenched by Fe³⁺ with a detection limit of 3.09 × 10^?7 mol L^?1. Using Fe³⁺ and EDTA as chemical inputs and the fluorescence intensity signal as outputs, FT‐HBCPNs films can be utilized as a logic gate at molecular level. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016 , 54, 3694–3700     

Bipyridinophane‐containing conjugated polymers modulated with an intramolecular aromatic C?H/π interaction

Bipyridinophane–fluorene conjugated copolymers have been synthesized via Suzuki and Heck coupling reactions from 5,8‐dibromo‐2,11‐dithia[3]paracyclo[3](4,4′)‐2,2′‐bipyridinophane and suitable fluorene precursors. Poly[2,7‐(9,9‐dihexylfluorene)‐co‐alt‐5,8‐(2,11‐dithia[3]paracyclo[3](4,4′)‐2,2′‐bipyridinophane)] ( P7 ) exhibits large absorption and emission redshifts of 20 and 34 nm, respectively, with respect to its planar reference polymer Poly[2,7‐(9,9‐dihexylfluorene)‐co‐alt‐1,4‐(2,5‐dimethylbenzene)] ( P11 ), which bears the same polymer backbone as P7 . These spectral shifts originate from intramolecular aromatic C? H/π interactions, which are evidenced by ultraviolet–visible and ¹H NMR spectra as well as X‐ray single‐crystal structural analysis. However, the effect of the intramolecular aromatic C? H/π interactions on the spectral shift in poly[9,9‐dihexylfluorene‐2,7‐yleneethynylene‐co‐alt‐5,8‐(2,11‐dithia[3]paracyclo[3](4,4′)‐2,2′‐bipyridinophane)] ( P10 ) is much weaker. Most interestingly, the quenching behaviors of these two conjugated polymers are largely dependent on the polymer backbone. For example, the fluorescence of P7 is efficiently quenched by Cu²⁺, Co²⁺, Ni²⁺, Zn²⁺, Mn²⁺, and Ag⁺ ions. In contrast, only Cu²⁺, Co²⁺, and Ni²⁺ ions can partially quench the fluorescence of P10 , but much less efficiently than the fluorescence of P7 . The static Stern–Volmer quenching constants of Cu²⁺, Co²⁺, and Ni²⁺ ions toward P7 are of the order of 10⁶ M^?1, being 1300, 2500, and 37,300 times larger than those of P10 , respectively. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 4154–4164, 2006     

Polymer‐based fluorescence sensors incorporating chiral binaphthyl and benzo[2,1,3]thiadiazole moieties for Hg2+ detection

Three chiral polymers P‐1 , P‐2 , and P‐3 could be obtained by the polymerization of (R)‐6,6′‐dibutyl‐3,3′‐diiodo‐2, 2′‐binaphthol (R‐M‐1) , (R)‐6,6′‐dibutyl‐3,3′‐diiodo‐2,2′‐bisoctoxy‐1,1′‐binaphthyl ( R‐M‐2 ), and (R)‐6,6′‐dibutyl‐3,3′‐diiodo‐2,2′‐bis (diethylaminoethoxy)‐1,1′‐binaphthyl ( R‐M‐3 ) with 4,7‐diethynyl‐benzo[2,1,3]‐thiadiazole ( M‐1) via Pd‐catalyzed Sonogashira reaction, respectively. P‐1 , P‐2 , and P‐3 can show pale red, blue–green, and orange fluorescence. The responsive optical properties of these polymers on various metal ions were investigated by fluorescence spectra. Compared with other cations, such as Co²⁺, Ni²⁺, Ag⁺, Cd²⁺, Cu²⁺, and Zn²⁺, Hg²⁺ can exhibit the most pronounced fluorescence response of these polymers. P‐1 and P‐2 show obvious fluorescence quenching effect upon addition of Hg²⁺, on the contrary, P‐3 shows fluorescence enhancement. Three polymer‐based fluorescent sensors also show excellent fluorescence response for Hg²⁺ detection without interference from other metal ions. The results indicate that these kinds of tunable chiral polybinaphthyls can be used as fluorescence sensors for Hg²⁺ detection. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 997–1006, 2010     

Optical and electronic properties of fluorene‐based copolymers and their sensory applications

A series of novel, fluorene‐based conjugated copolymers, poly[(9,9‐bis{propenyl}‐9H‐fluorene)‐co‐(9,9‐dihexyl‐9H‐fluorene)] ( P1 ), poly[(9,9‐bis{carboxymethylsulfonyl‐propyl}fluorenyl‐2,7‐diyl)‐co‐(9,9‐dihexyl‐9H‐fluorene)] ( P2 ) and poly[(9,9‐dihexylfluorene)‐co‐alt‐(9,9‐bis‐(6‐azidohexyl)fluorene)] ( P3 ), are synthesized by Suzuki coupling reactions and their electrochemical properties, in the form of films, are investigated using cyclic voltammetry. The results reveal that the polymer films exhibit electrochromic properties with a pseudo‐reversible redox behavior; transparent in the neutral state and dark violet in the oxidized state. Among the three polymers, P2 possesses the shortest response time and the highest coloration efficiency value. These polymers emit blue light with a band gap value of around 2.9 eV and have high fluorescent quantum yields. Their metal ion sensory abilities are also investigated by titrating them with a number of different transition metal ions; all of these polymers exhibit a higher selectivity toward Fe³⁺ ions than the other ions tested with Stern–Volmer constants of 4.41 × 10⁶M^?1, 3.28 × 10⁷M^?1, 1.25 × 10⁶M^?1, and 6.56 × 10⁶M^?1 for P1 , P2 , water soluble version of P2 ( P2S ) and P3 , respectively. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013     

Blue‐light‐emitting polyfluorene functionalized with triphenylamine and cyanophenylfluorene bipolar side chains

A new bipolar conjugated polyfluorene copolymer with triphenylamine and cyanophenylfluorene as side chains, poly{[9,9‐di(triphenylamine)fluorene]‐[9,9‐dihexyl‐fluorene]‐[2,7‐bis(4′‐cyanophenyl)‐9,9′‐spirobifluorene]} ( PTHCF ), was synthesized for studying the polymer backbone emission. Its absolute weight‐average molecular weight was determined as 4.85 × 10⁴ by using gel permeation chromatography with a multiangle light scattering detector. In contrast to the electronic absorption spectrum in dilute solution, the absorbance of PTHCF in thin film was slightly blue shifted. By comparison of the solution and thin‐film photoluminescence (PL) spectra, a red shift of Δλ = 8–9 nm was observed in the thin‐film PL spectrum. The HOMO and LUMO energy levels of the resulting polymer were electrochemically estimated as ?5.68 and ?2.80 eV, respectively. Under the electric‐field intensity of 4.8 × 10⁵ V cm^?1, the obtained hole and electron mobilities were 2.41 × 10^?4 and 1.40 × 10^?4 cm² V^?1 s^?1, respectively. An electroluminescence device with configuration of ITO/PEDOT:PSS/ PTHCF _70%+PBD_30%/CsF/Ca/Al exhibited a deep‐blue emission as a result of excitons formed by the charges migrating along the full‐fluorene main chain. The incorporation of the bipolar side chains into the polymer structure prevented the intermolecular interaction of the fluorene moieties, balance charge injection/transport, and thereby improve the polymer backbone emission. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010     

Water‐soluble anionic conjugated polymers for metal ion sensing: Effect of interchain aggregation

Three sulfonato‐containing fluorene‐based anionic water‐soluble conjugated polymers, which are specially designed to link fluorene with alternating moieties such as bipyridine ( P1 ), pyridine ( P2 ), and benzene ( P3 ) have been synthesized via the Pd‐catalyzed Sonogashira‐coupling reaction, respectively. These polymers had good solubility in water and showed different responses for transition metal ions with different valence in aqueous environments: the fluorescence of bipyridine‐containing P1 can be completely quenched by addition of all transition metal ions selected and showed a good selectivity for Ni²⁺; the pyridine‐containing P2 had a little response for monovalent and divalent metal ions while showed good quenching with the addition of trivalent metal ions (with a special selectivity for Fe³⁺); P3 had responses only for the trivalent metal ions within the ionic concentration we studied. After investigation of the UV‐vis absorption spectra, PL emission spectra, DLS, and fluorescence lifetime of P1 – P3 in aqueous solution when adding transition metal ions, we found that the different spectrum responses of these polymers are attributed to the different coordination ability of the units linked with fluorene in the main chain. The energy or electron‐transfer reactions were the main reason for fluorescence quenching of P1 and P2 . On the other hand, interchain aggregation caused by trivalent metal ions lead to fluorescence quenching for P3 and also caused partly fluorescence quenching of P1 and P2 . These results revealed the origin of ionochromic effects of these polymers and suggested the potential application for these polymers as novel chemosensors with higher sensing sensitivity in aqueous environments. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 5057–5067, 2009     

Electrochemical fluorescence switching properties of conjugated polymers composed of triphenylamine,fluorene, and cyclic urea moieties

The study of the electrochemical fluorescence switching properties of the conjugated copolymers containing fluorene, triphenylamine, and 1,3‐diphenylimidazolidin‐2‐one moieties is reported. The polymers show high fluorescence quantum yields, excellent thermal stability, and good solubility in polar organic solvents. While the polymer emits blue light under UV irradiation, the fluorescence intensity is quenched upon electrochemical oxidation. The fluorescent behavior can be reversibly switched between nonfluorescent (oxidized) state and strong fluorescence (neutral) state with a high contrast ratio (I_f/I_f0) of 16.3. The role of the electrochemical oxidation of the triphenylamine moieties is to generate the corresponding radical cations that lead to fluorescence quenching in the solid matrix. © 2012 Wiley Periodicals, Inc. J. Polym. Sci. Part A: Polym Chem, 2012     

Dimedone‐decorated conjugated polymer: Tandem knoevenagel‐michael post‐modification synthesis and its application as optical probe for Hg2+ and ClO− in high‐water‐fraction mediums

High‐efficiency, mild‐conditioned tandem Knoevenagel–Michael reaction was utilized to post‐modify aldehyde‐containing, triphenylamine‐based precursor conjugated polymer ( CP1 ) to afford dimedone‐decorated aimed polymer ( CP2) . The chemical structure of CP2 was verified by FTIR and ¹H NMR analyses. With the introduction of aqueous Hg²⁺, fluorescence of CP2 in THF‐water mixture (V _THF/V _water = 1/100) (buffered with 5 mM sodium dihydrogen phosphate‐disodium hydrogen phosphate (PB), pH = 7.4) altered significantly, with the emission changed from blue to orange. Besides this, CP2 also displayed specific optical response to ClO^? in another probing medium (V _THF/V _water = 1/100, buffered with 50 mM PBS (with NaCl in PB, pH = 7.4). The detailed probing process and the plausible detection mechanism of CP2 to Hg²⁺ and ClO^? were systematically investigated here. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55 , 1067–1076     

Optical,electrochemical, and sensing properties of polyfluorenes bearing thiazole or oxazole and triphenylamine in the main chain

Polyfluorenes bearing thiazole (PFTH) or oxazole (PFOX) heterocyclic units as well as triphenylamine (TPA) in the main chain were synthesized. The ratio of thiazole or oxazole/TPA in the polymer chain varies from 100/0 to 25/75. The optical properties of polymers depend on thiazole or oxazole contents. Cyclic voltammetry reveals that thiazole or oxazole hinder the oxidation of polymers and only polymers with TPA show reversible oxidation. The Electron Affinities do not practically depend on composition of the polymer chain. The sensing properties of polymers PFTH100 and PFOX100 are investigated toward several cations and anions. Polymers detect two analytes, Fe²⁺ and Hg²⁺. PL quenching shows linear response to Fe²⁺ in wide concentration region 1–800 μΜ. I^? anions quench the emission of polymers. Hg²⁺ turns on the emission of the polymer/I^? complex at concentrations as low as 1 μM. Enhancement of polymer/I^? emission exhibits linear response to Hg²⁺ concentration. PFTH100 is able to detect Fe²⁺ and Hg²⁺ that coexist in a solution. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55 , 243–254     

Synthesis of a novel poly(para‐phenylene ethynylene) for highly selective and sensitive sensing mercury (II) ions

A new poly(p‐phenylene ethynylene) derivative with pendant 2,2′‐bipyridyl groups and glycol units (PPE‐bipy) has been prepared, and its metal ion sensing properties were investigated. The polymer of PPE‐bipy exhibited high selectivity for Hg²⁺ as compared with Li⁺, Na⁺, K⁺, Ba²⁺, Ca²⁺, Mg²⁺, Al³⁺, Mn²⁺, Ag⁺, Zn²⁺, Pb²⁺, Ni²⁺, Cd²⁺, Cu²⁺, Co,²⁺ and Fe³⁺ in THF/EtOH (1:1, v/v) solution. The fluorescence of PPE‐bipy was efficiently quenched by Hg²⁺ ions, and the detection limit was found to be 8.0 nM in a THF/EtOH (1:1, v/v) solvent system. PPE‐bipy also showed a selective chromogenic behavior toward Hg²⁺ ions by changing the color of the solution from slight yellow to colorless, which can be detected with the naked eye. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 1998–2007, 2008     

Synthesis and nonlinear optical properties of polyacetylenes containing oxadiazole and thiophene pendant groups with high thermal stability

A series of random copolymers poly(3‐ethynylthiophene)‐copoly(2‐(4‐decyloxyphenyl)‐5‐(4‐ethynylphenyl)‐1,3,4‐oxadiazole) with different oxadiazole content ( P2 – P4 ) and homopolymer poly(3‐ethynylthiophene) ( P1 ) as well as poly(2‐(4‐decyloxyphenyl)‐5‐(4‐ethynylphenyl)‐1,3,4‐oxadiazole) ( P5 ) were prepared. The copolymers ( P2 – P4 ) are completely soluble in common organic solvents. The structures and properties of all polymers were characterized and evaluated by FTIR, ¹H NMR, ¹³C NMR, TGA, UV, PL, GPC, and nonlinear optical (NLO) analyses. The incorporation of diaryl‐oxadiazole into polyacetylene‐containing thiophene significantly endows copolymers with higher thermal stability, which may origin from the synergetic effect of the “jacket effect” of diaryl‐oxadiazole units and the effect of retarding or eliminating a few 6π‐electrocycliaztion proceeds of oxadiazole‐containing polyacetylene due to the hindrance of thiophene units. When the copolymer ( P3 ) posses more regular alternating thiophene pendants and oxadiazole pendants arrangement along the polymer backbone, it shows good thermal stability (T_d up to 388 °C) and larger third‐order nonlinear optical susceptibility (χ(3) up to 11.0 × 10^?11 esu). © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010     

Hole‐transporting host‐polymer series consisting of triphenylamine basic structures for phosphorescent polymer light‐emitting diodes

A series of novel styrene derived monomers with triphenylamine‐based units, and their polymers have been synthesized and compared with the well‐known structure of polymer of N,N′‐bis(3‐methylphenyl)‐N,N′‐diphenylbenzidine with respect to their hole‐transporting behavior in phosphorescent polymer light‐emitting diodes (PLEDs). A vinyltriphenylamine structure was selected as a basic unit, functionalized at the para positions with the following side groups: diphenylamine, 3‐methylphenyl‐aniline, 1‐ and 2‐naphthylamine, carbazole, and phenothiazine. The polymers are used in PLEDs as host polymers for blend systems with the following device configuration: glass/indium–tin–oxide/PEDOT:PSS/polymer‐blend/CsF/Ca/Ag. In addition to the hole‐transporting host polymer, the polymer blend includes a phosphorescent dopant [Ir(Me‐ppy)₃] and an electron‐transporting molecule (2‐(4‐biphenyl)‐5‐(4‐tert‐butylphenyl)‐1,3,4‐oxadiazole). We demonstrate that two polymers are excellent hole‐transporting matrix materials for these blend systems because of their good overall electroluminescent performances and their comparatively high glass transition temperatures. For the carbazole‐substituted polymer (T_g = 246 °C), a luminous efficiency of 35 cd A^?1 and a brightness of 6700 cd m^?2 at 10 V is accessible. The phenothiazine‐functionalized polymer (T_g = 220 °C) shows nearly the same outstanding PLED behavior. Hence, both these polymers outperform the well‐known polymer of N,N′‐bis(3‐methylphenyl)‐N,N′‐diphenylbenzidine, showing only a luminous efficiency of 7.9 cd A^?1 and a brightness of 2500 cd m^?2 (10 V). © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 3417–3430, 2010     

Synthesis and characterization of nitrogen‐linked carbazole‐containing fluorescent polymers

We have prepared four light‐emitting polymers bearing a chromophore composed of carbazole and fluorene by the Suzuki coupling polycondensation. Two nonconjugated polymers (P3CzBFXy and P2CzFXy) had a chromophore tethered by the p‐xylylene spacer, whose connection point between carbazole and fluorene in addition to the number of fluorene unit was systematically changed to investigate the emission wavelength and intensity. The red‐shifted absorption and emission maximum wavelengths together with the improved fluorescence quantum yield of polymers P3CzBFXy and P2CzFXy indicate that the increment of the number of para‐connected benzene rings included in the chromophore effectively extends the conjugation length. The fact that polymer P3CzBFXy has longer wavelength absorption and emission spectra also indicates the interaction of the carbazole nitrogen lone pair with the oligophenylene moiety. Other two polymers P3CzFPy and P3CzFPym having the heterocycle directly bound to the carbazole nitrogen were prepared to know the character of the carbazole nitrogen lone pair and their influence on the fluorescence behavior. The fluorescence spectra of polymer P3CzFPym bearing the pyrimidine ring gradually red‐shifted in conjunction with the decrease of fluorescence quantum yield on going from toluene solution to CHCl₃ solution because of the intramolecular charge transfer at the excited state. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 3729–3735, 2010     

Novel triarylamine‐based alternating conjugated polymer with high hole mobility: Synthesis,electro‐optical,and electronic properties

Novel bi‐triphenylamine‐containing aromatic dibromide M3 , N,N‐bis(4‐bromophenyl)‐N′,N′‐dipheny‐l,4‐phenylenediamine, was successfully synthesized. The novel conjugated polymer P1 having number‐average molecular weight of 1.31 × 10⁴ was prepared via Suzuki coupling from the dibromide M3 and 9,9‐dioctylfluorene‐2,7‐diboronic acid bis(1,3‐propanediol) ester. Polymer P1 had excellent thermal stability associated with a high glass‐transition temperature (T_g = 141 °C). The hole‐transporting and UV‐vis‐near‐infrared electrochromic properties were examined by electrochemical and spectroelectrochemical methods. Cyclic voltammograms of the conjugated polymer films cast onto indium‐tin oxide‐coated glass substrates exhibited two reversible oxidation redox couples at E_1/2 values of 0.73 and 1.13 V versus Ag/Ag⁺ in acetonitrile solution. The hole mobility of the conjugated polymer P1 revealed ～10^?3 cm² V^?1 s^?1, which is much higher than that of other conjugated polymer systems. The observed UV‐vis‐near‐infrared absorption change in the conjugated polymer film P1 at applied potentials ranging from 0.00 to 1.23 V are fully reversible and associated with strong color changes from pale yellowish in its neutral form to green and blue in its oxidized form. Using a combination of experimental study and theoretical investigation, we proposed an oxidation mechanism based on molecular orbital theory, which explains the cyclic voltammetry experimental results well. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010     

Synthesis and selective recognition toward zinc ion of chiral poly(imine‐triazole)

A novel AB type of clickable monomer, (S)‐2‐[(2‐azido‐1‐phenylethylimino)methyl]‐5‐propargyloxyphenol (AMPP) was designed and polymerized to yield a class of main‐chain chiral poly(imine‐triazole)s through the metal‐free click reaction. With the thermally induced polymerization, the desired polytriazoles can be easily prepared in high yields by a stepwise heating‐up process and have the number‐average molecular masses ranging from 5.1 × 10³ to 58.1 × 10³ (polydispersity indices = 1.38?1.68). The polymers were characterized by Fourier Transform Infrared spectroscopy (FTIR), ¹H Nuclear Magnetic Resonance (NMR), and gel permeation chromatography, and their optical properties were studied by fluorescence and circular dichroism (CD) spectroscopies. As a chemosensor, these polymers exhibited a selective “turn‐on” fluorescence enhancement response toward Zn²⁺ ion over other cations such as Na⁺, K⁺, Mg²⁺, Ca²⁺, Ag⁺, Pb²⁺, Cd²⁺, Hg²⁺, Mn²⁺, and Ni²⁺ in dimethyl sulfoxide. However, the Zn²⁺‐induced fluorescence signal was subject to serious interference by Al³⁺, Cu²⁺, Cr³⁺, and Fe³⁺ ions. Interestingly, the chiral polymer showed distinctive changes in the CD spectra on complexation with Zn²⁺, which allowed for the discrimination of this ion in the presence of other species tested including those interfering ions observed in the fluorescent detection. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 2248–2257     

A multifunctional poly(aryl ether) with oligoaniline and fluorene pendants: Synthesis,electrochromic performance,and tunable fluorescent properties

A novel multifunctional poly(aryl ether) with both pendant oligoaniline and fluorene groups (PAE‐p‐OF) was synthesized by nucleophilic polycondensation and characterized by ¹H NMR, Fourier‐transform infrared spectra, and gel permeation chromatography. The polymer showed excellent solubility in common organic solvents and good thermal stability. Electrochemical and photophysical properties were also investigated using cyclic voltammetry, UV–vis, and fluorescence spectroscopies. The obtained PAE‐p‐OF exhibits satisfactory electrochromic properties with high contrast value, acceptable coloration efficiency, and moderate switching times. Moreover, the fluorescence intensity of PAE‐p‐OF was modulated by controlling oxidation degree of oligoaniline moiety, due to the energy migration occurring between oligoaniline and fluorene groups. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012     

Meta‐linked and para‐linked water‐soluble poly(arylene ethynylene)s with amino acid side chains: Effects of different linkage on Hg2+ ion sensing properties in aqueous media

Water‐soluble, meta‐ and para‐linked poly(arylene ethynylene)s containing L ‐aspartic acid‐functionalized fluorene units (P1 and P2) and their model compounds (M1 and M2) have been synthesized, and their photophysical properties and fluorescent sensing properties were investigated in aqueous solution. P1 and M1 with the meta‐linkage show blue‐shifted absorption and emission spectra, and decreased photoluminescence quantum yields compared with those of P2 and M2 with para‐linkage. Their absorption and fluorescence spectra are pH dependent perhaps due to the aggregation of the polymer chains at low pH values. In buffer solutions, both polymers and their model compounds exhibit the excellent selectivity and sensitivity to Hg²⁺ over other common metal ions. Furthermore, the quenching constant and detection limit of P1 are determined to be 1.04 × 10⁷ M^?1 and 10 nM, and show the higher sensitivity compared to P2. Further comparison of their model compounds reveal that the sensitivity and quenching efficiency of M1 is also higher than that of M2, indicating that the meta‐linkage pattern plays a key role in improving their Hg²⁺ ion sensing properties. In addition, both meta‐ and para‐linked polymers exhibit the higher quenching efficiency than their model compounds due to the amplified fluorescence response of conjugated polymer. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012     

Blue light‐emitting hyperbranched polymers using fluorene‐co‐dibenzothiophene‐S,S‐dioxide as branches

A series of blue light‐emitting hyperbranched polymers comprising poly(fluorene‐co‐dibenzothiophene‐S,S‐dioxide) as the branch and benzene, triphenylamine, or triphenyltriazine as the core were synthesized by an “A₂ + A₂' + B₃” approach of Suzuki polymerization, respectively. All resulted copolymers exhibited quite comparable thermal properties with the glass transition temperatures in the range of 59–68 °C and relatively high decomposition temperatures over 420 °C. Photoluminescent spectra exhibited slight variation with the molar ratio of the dibenzothiophene‐S,S‐dioxide unit and the size of the core units. Polymer light‐emitting devices demonstrated blue emission with excellent stability of electroluminescence. Copolymers based on smaller core units of benzene and triphenylamine exhibited enhanced device performances regarding to that of triphenyltriazine. With the device configuration of ITO/PEDOT:PSS/polymer/CsF/Al, a maximum luminous efficiency of 4.5 cd A^?1 was obtained with Commission Internationale de L'.Eclairage (CIE) coordinates of (0.16, 0.19) for the copolymer PFSO15B. These results indicated that hyperbranched structure can be a promising strategy to attain spectrally stable blue‐light‐emitting polymers with high efficiency. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015 , 53, 1043–1051     

Salicylaldimine‐functionalized poly(m‐phenyleneethynylene) as turn‐on chemosensor for ferric ion

A new turn on fluorescent probe for ferric ion based on poly(m‐phenyleneethynylene salicylaldimine) ( PPE‐IM ) has been developed. The preparation of PPE‐IM involves post‐polymerization functionalization of the corresponding polymeric amine, PPE‐AM , via the condensation with salicylaldehyde. The degree of polymerization of both PPE‐IM and PPE‐IM is 17 with polydispersity index of 1.5. In aqueous solution, the polymeric PPE‐IM is highly stable unlike its small molecule analog which is gradually hydrolyzed. The weak fluorescence of initial PPE ‐ IM (λ_em = 470) is greatly enhanced by 300 folds upon the addition of Fe³⁺. The ¹H NMR reveals that the fluorescence enhancement is caused by Fe³⁺‐induced hydrolysis of the imine group. The sensing system shows a detection limit of 0.14 μM of Fe³⁺. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018 , 56, 1155–1161