Fast switching immobilized photochromic dyes

A novel photochromic dye conjugate architecture is described, which allows both covalent tethering to a polymeric host matrix and fast photochromic switching. The new conjugates consist of a photochromic dye covalently bound to two different substituents via a Y‐branching linker (hetero Y‐branching), one being a polymerizable methacrylate moiety and the other a soft (low T_g) poly(dimethylsiloxane) oligomer. The novel conjugates gave faster photochromic decoloration in the host lens matrix compared with the electronically equivalent nonmatrix‐bound and unconjugated parent control dyes. In addition, further acceleration of fade speed kinetics was observed with a longer linker between photochromic dye and methacrylate moiety. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011     

Blue‐emitting poly[(m‐phenylene vinylene)‐alt‐(o‐phenylene vinylene)]s: The effect of regioregularity on the optical properties

Poly[(m‐phenylene vinylene)‐alt‐(o‐phenylene vinylene)]s with different contents of cis‐/trans‐CH?CH ( 3 and 6 ) have been synthesized through Wittig condensation. The polymers exhibit good solubility in common organic solvents such as toluene and tetrahydrofuran. A comparison of the optical properties has been made between 3 and its phenyl regioisomers containing either p‐phenylene or m‐phenylene units. The results show that the regiochemistry of the phenyl ring can be a useful tool for tuning the emission color of π‐conjugated polymers because the extension of π conjugation can only partially be achieved through an o‐phenylene bridge. Although both polymers 3 and 6 exhibit comparable low fluorescence quantum efficiencies (≈0.18) in solution, their films are highly luminescent, showing a broad emission band near 456 nm (blue color). Electroluminescence results show that the device of polymer 3 , which has a higher content of trans‐CH?CH linkages, is about 20 times more efficient than that of 6 . © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 2650–2658, 2003     

Syntheses of terminally functionalized polyisobutylene derivatives using diazonium salts

A new strategy for the synthesis of end‐functionalized polyisobutylene (PIB) oligomers is detailed. Commercially available vinyl‐terminated PIB oligomers were modified to form aniline‐terminated PIB via an aromatic electrophilic substitution reaction. The PIB‐bound aryl amines so formed were then converted into diazonium salts using isopentyl nitrite and an acid in methylene chloride. These salts served as versatile intermediates in synthetic reactions affording azo dye‐containing PIB derivatives and other terminally‐functionalized PIB derivatives not readily available by other reactions. The advantages and limitations of various name reactions including diazo couplings, Sandmeyer reactions, dediazoniations, and Heck reactions are discussed. The kinetics of polar substitution reactions at the termini of these nonpolar oligomers and the effects of solvent on these reactions were also examined. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011     

Syntheses,characterization, and properties of multiblock copolymers consisting of polyisobutylene and poly(L‐lactide) segments

The syntheses of {‐poly(L ‐lactide) (PLLA)‐b‐polyisobutylene (PIB)‐}_n multiblock copolymers were accomplished for the first time by chain extension of PLLA‐b‐PIB‐b‐PLLA triblock copolymers. Well‐defined PLLA‐b‐PIB‐b‐PLLA triblock copolymers with predictable M_ns, low PDIs (1.10–1.18) and excellent blocking efficiencies were prepared by anionic ring‐opening polymerizations of L ‐lactide initiated with hydroxyallyl telechelic PIB (HO‐Allyl‐PIB‐Allyl‐OH) in toluene at 110 °C. The triblock copolymers were successfully chain extended with 4,4′‐methylenebis(phenylisocyanate) (MDI) to obtain the multiblock copolymers with good gravimetric yields of ～86 to 96%. The chain‐extended polymers were soluble in a range of common organic solvents. The block copolymers showed two glass transition temperatures in differential scanning calorimetric analysis for the PIB and PLLA blocks indicating microphase separation, which was supported by atomic force microscopy images. The as‐synthesized compression molded multiblock copolymers exhibited tensile strengths in the range of 8–24 MPa with elongations at break in the range of 2.5–400%. The static and dynamic mechanical properties showed a strong dependence on the relative PLLA content in the copolymer. The dynamic mechanical analysis also indicated microphase separation at higher PLLA compositions. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 3490–3505, 2009     

Synthesis and optical properties of a poly(p‐phenylenevinylene) derivative and polyfluorenes with bipolar groups along the main chain

A poly(p‐phenylenevinylene) derivative (PPV–TPA)] and a series of statistical copolyfluorenes (PF–TPA)] containing oxadiazole and triphenylamine segments along the main chain were synthesized by the Heck reaction and nickel‐mediated coupling, respectively. The PF–TPA copolyfluorenes with relatively low contents of oxadiazole and triphenylamine units were readily soluble in common organic solvents, whereas the other copolyfluorenes displayed lower solubility. PPV–TPA showed excellent solubility in solvents such as tetrahydrofuran (THF), dichloromethane, chloroform, and toluene. Thin films of the polymers absorbed light in the range of 375–396 nm and had optical band gaps of 2.76–2.98 eV. They emitted blue‐green light with a maximum at 414–522 nm. The fluorescence quantum yields in THF solutions were 0.08–0.53. The copolyfluorene PF–TPA thin films with high contents of oxadiazole and triphenylamine moieties emitted pure blue light that remained stable even after annealing at 150 °C for 4 h in air. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 3556–3566, 2006     

Poly(ether ketone)–polyisobutylene block copolymers: Synthesis and phase behavior

Telechelic poly(ether ketone)s (PEKs) and polyisobutylenes (PIBs) were combined to form PIB? PEK? PIB triblock copolymers and (PIB? PEK)_n multiblock copolymers via the formation of urea linkages. Monovalent and bivalent amino telechelic PIBs were prepared quantitatively from allyl telechelic PIBs by a newly developed reaction sequence featuring nucleophilic reaction steps. Telechelic PEK? NCO polymers were prepared from the corresponding amino telechelic PEKs via a reaction with diphosgene. The highly reactive PEK? NCO and PIB? NH₂ telechelics formed PEK? PIB block copolymers only quantitatively when appropriately reactive primary amino groups were present on the amino telechelic PIBs. The obtained block copolymers were microphase‐separated and featured mostly lamellar structures, as determined by small‐angle X‐ray scattering (SAXS). Temperature‐dependent SAXS measurements revealed ordered polymers in the melt up to 210 °C. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 188–202, 2005     

New series of highly phenyl‐substituted polyfluorene derivatives for polymer light‐emitting diodes

A new series of highly phenyl‐substituted polyfluorene derivatives were synthesized and characterized. The resulting polymers were amorphous and showed excellent solubility in common organic solvents, such as chloroform, tetrahydrofuran, xylene, toluene, chlorobenzene, and so forth. All possessed satisfied thermal stability with glass‐transition temperatures (T_g's) in the range of 79–115 °C. They emitted blue light with photoluminescent (PL) maximum peaks at about 408–412 nm in thin films. The PL efficiencies of the polymer films were measured around 30–33%. The highly phenylated pendants improved the T_g of polyfluorene without forming defects in the polymers and reduced their tendency to form aggregate/excimers. Polymer light‐emitting diodes were fabricated from these polymers with the configuration of indium tin oxide/polyethylenedioxythiophene:polystyrene sulfonic acid/polymer/Ba/Al, which emitted bright blue light with maximum peaks at 418–420 nm. The maximum external quantum efficiencies of these devices were 0.41–0.6%. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 2985–2993, 2004     

Synthesis of fluorene‐based high performance polymers. I. Poly(arylene thioether)s with excellent solubility and high refractive index

Several poly(arylene thioether)s ( PTEs ) containing a fluorene moiety were synthesized by the polycondensation of masked dithiols such as 9,9‐bis(4‐(N,N‐dimethyl‐S‐carbamoyl)phenyl)fluorene and various difluoroarenes. All PTEs were obtained in quantitative yields. The PTEs showed good thermal stability: the 10% weight loss temperature was over 480 °C under both nitrogen and air atmosphere by TGA, and glass temperature was within a range of 204–275 °C by DSC. Most PTEs exhibited remarkably high refractive index values in a range of 1.66–1.72 at 589 nm, whereas they had a very low degree of birefringence properties. Furthermore, the PTEs showed high solubility in ordinary organic solvents such as chloroform, N‐methylpyrrolidone, and tetrahydrofuran. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 3073–3082, 2007     

Aromatic poly(1,3,4‐oxadiazole)s and poly(amide‐1,3,4‐oxadiazole)s containing ether sulfone linkages

Polyhydrazides and poly(amide‐hydrazide)s were prepared from two ether‐sulfone‐dicarboxylic acids, 4,4′‐[sulfonylbis(1,4‐phenylene)dioxy]dibenzoic acid and 4,4′‐[sulfonylbis(2,6‐dimethyl‐1,4‐phenylene)dioxy]dibenzoic acid, or their diacyl chlorides with terephthalic dihydrazide, isophthalic dihydrazide, and p‐aminobenzhydrazide via a phosphorylation reaction or a low‐temperature solution polycondensation. All the hydrazide polymers were found to be amorphous according to X‐ray diffraction analysis. They were readily soluble in polar organic solvents such as N‐methyl‐2‐pyrrolidone and N,N‐dimethylacetamide and could afford colorless, flexible, and tough films with good mechanical strengths via solvent casting. These hydrazide polymers exhibited glass‐transition temperatures of 149–207 °C and could be thermally cyclodehydrated into the corresponding oxadiazole polymers in the solid state at elevated temperatures. Although the oxadiazole polymers showed a significantly decreased solubility with respect to their hydrazide prepolymers, some oxadiazole polymers were still organosoluble. The thermally converted oxadiazole polymers had glass‐transition temperatures of 217–255 °C and softening temperatures of 215–268 °C and did not show significant weight loss before 400 °C in nitrogen or air. For a comparative study, related sulfonyl polymers without the ether groups were also synthesized from 4,4′‐sulfonyldibenzoic acid and the hydrazide monomers by the same synthetic routes. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 2271–2286, 2001     

Phase separation and permeability in polyisobutylene‐based miktoarm star polymers

The phase behavior of (PS‐PIB)₂‐s‐PAA miktoarm star terpolymers with varying volume fractions of PAA was investigated directly by transmission electron microscopy, atomic force microscopy, and small‐angle X‐ray scattering, and indirectly by thermogravimetric analysis and degree of water sorption. The microdomains of (PS‐PIB)₂‐s‐PAA demonstrate a unique and unexpected progression from highly ordered cylinders, to lower ordered spheres, to gyroid structures with increasing PAA content from 6.6 to 47 wt %. Interestingly, the phase behavior in the miktoarm star polymer system is significantly different from that reported previously for the linear counterpart of similar composition (PAA‐PS‐PIB‐PS‐PAA), where a steady progression from cylindrical to lamellar morphology was observed with increasing PAA content. At low PAA concentrations, the morphology is driven primarily by the relative solubility of the components, while at high PAA content the molecular architecture dominates. Thermal annealing demonstrated the thermodynamic stability of the morphologies, indicating the potential for design of novel microstructures for specific applications through precise control of architecture, composition, and interaction parameters of the components. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2016 , 54, 916–925     

Blue light‐emitting poly(p‐phenylenevinylene) derivatives containing alternating conjugated segments and aliphatic spacers

Two new poly(p‐phenylenevinylene) derivatives were prepared by Heck coupling. They contained alternating conjugated segments on the basis of p‐distyrylbenzene and flexible nonconjugated spacers. The synthesized polymers P1 and P2 carried two m‐terphenyl of four tertbutyl pendants, respectively, per repeat unit. Both polymers were amorphous and exhibited satisfactory thermal stability. Polymer P1 displayed a limited solubility in common organic solvents, whereas P2 dissolved readily in these solvents. The glass‐transition temperature values were 128 °C for P1 and 37 °C for P2 . The polymers emitted blue or violet‐blue light with photoluminescent maxima at about 445 and 460 nm for solutions and thin films, respectively. The bulky pendants reduced their tendency to form aggregates. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 1091–1098, 2003     

ATNRC/SET‐NRC synthesis of graphene/polyisobutylene nanocomposites

Two polyisobutylene‐grafted graphene nanocomposites were prepared by CuBr‐catalyzed atom transfer nitroxide radical coupling (ATNRC) and Cu‐catalyzed single electron transfer‐nitroxide radical coupling (SET‐NRC) chemistry under mild conditions, respectively, through the grafting‐onto strategy. Graphene oxide was first reduced to graphene by diazonium addition reaction followed by treating graphene with ethyl 2‐bromoisobutyrate for introducing Br‐containing groups onto the surface to give G‐Br. The presynthesized well‐defined functional polyisobutylene (PIB) possessing 2,2,6,6‐tetramethylpiperidine‐1‐oxyl terminal group obtained via cationic polymerization of isobutylene was then coupled with G‐Br through ATNRC or SET‐NRC at room temperature to afford polymer‐modified graphene, G‐PIB. SET‐NRC method has a faster coupling rate using cheaper reagent (Cu wire instead of CuBr) in comparison with ATNRC approach. Detailed characterizations including FT‐IR, Raman, ¹H NMR, TGA, AFM, and TEM assured us of successful anchoring of PIB chains onto the surface of graphene sheets. The resulting G‐PIB nanocomposites still maintain the separated single layers in dispersion and the dispersibilities in organic solvents are significantly improved. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013 , 51, 4505–4514     

Fluorine‐containing vinyl ether polymers: Living cationic polymerization in fluorinated solvents as new media and unique solubility characteristics in organic solvents

Living cationic polymerization of fluorine‐containing vinyl ethers [CH₂?CH? O? C₂H₄? O? C₃H₆? C_nF_2n+1: 5FVE (n = 2), 13FVE (n = 6)] was investigated in various solvents with a CH₃CH(OiBu)OCOCH₃/Et_1.5AlCl_1.5 initiating system in the presence of an added base. 5FVE was polymerized quantitatively in toluene at 0 °C, and the obtained polymers had predetermined molecular weights with narrow molecular weight distributions (M_w/M_n < 1.1). On the other hand, for the polymerization of 13FVE, the product polymers precipitated due to their extremely poor solubility in nonfluorinated organic solvents. Therefore, fluorinated solvents such as hydrochlorofluorocarbons, hydrofluorocarbons, hydrofluoroethers, or α,α,α‐trifluorotoluene, as‐yet uninvestigated for cationic polymerization, were employed. In these solvents, living polymerization was achieved even with 13FVE, yielding well‐defined polymers (M_w/M_n < 1.1, by size exclusion chromatography using a fluorinated solvent as an eluent). The solvents were also shown to be good for living polymerization of isobutyl vinyl ether. The obtained fluorine‐containing polymers underwent temperature‐responsive solubility transitions in organic solvents. Poly(5FVE) showed sensitive upper critical solution temperature (UCST)‐type phase separation behavior in toluene. Copolymers of 13FVE and isobutyl vinyl ether showed UCST‐type phase separation in common organic solvents with different polarities depending on their composition, while a homopolymer of 13FVE was insoluble in all nonfluorinated organic solvents. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011     

Synthesis of fluorinated polybenzoxazoles with low dielectric constants

Two fluorinated aromatic bis(o‐aminophenol)s, 1,1‐bis(3′‐amino‐4′‐hydroxyphenyl)‐1‐(3′‐trifluoromethylphenyl)‐2,2,2‐trifluoroethane (6FAP) and 1,1‐bis(3′‐amino‐4′‐hydroxyphenyl)‐1‐(3′,5′‐ditrifluoromethylphenyl)‐2,2,2‐trifluoroethane (9FAP) were synthesized, which were allowed to polycondense with aromatic diacyl chlorides to afford the fluorinated aromatic polybenzoxazoles (PBOs) via a conventional two‐step procedure in which the low‐temperature solution polycondensation process was first performed to yield poly(o‐hydroxyamide)s (PHAs) followed by the thermal cyclodehydration to give the PBOs. Experimental results indicated that the PHAs had inherent viscosities in the range of 0.29–0.68 dL/g, showing excellent solubility in organic solvents. The PHAs could be thermally cyclodehydrated into the corresponding PBOs at 260–370 °C. The obtained PBOs exhibited enhanced glass‐transition temperature but decreased solubility with respect to the PHAs. The PBOs showed glass‐transition temperatures in the range of 315–337 °C and excellent thermal stabilities with 5% original weight‐loss temperatures (T₅) of >513 °C. Additionally, the PBO films had average refractive index of 1.5298–1.5656, birefringence of 0.0051–0.0092, and low dielectric constants of 2.57–2.70. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010     

Construction of PIB‐b‐PDEAEMA well‐defined amphiphilic diblock copolymers via sequential living carbocationic and RAFT polymerization

A series of well‐defined amphiphilic diblock copolymers consisting of hydrophobic polyisobutylene (PIB) and hydrophilic poly(2‐(diethylamino)ethyl methacrylate) (PDEAEMA) segments was synthesized via the combination of living carbocationic polymerization and reversible addition fragmentation chain transfer (RAFT) polymerization. Living carbocationic polymerization of isobutylene followed by end‐capping with 1,3‐butadiene was first performed at ?70 °C to give a well‐defined allyl‐Cl‐terminated PIB with a low polydispersity (M_w/M_n =1.29). This end‐functionalized PIB was further converted to a macromolecular chain transfer agent for mediating RAFT block copolymerization of 2‐(diethylamino)ethyl methacrylate at 60 °C in tetrahydrofuran to afford the target well‐defined PIB‐b‐PDEAEMA diblock copolymers with narrow molecular weight distributions (M_w/M_n ≤1.22). The self‐assembly behavior of these amphiphilic diblock copolymers in aqueous media was investigated by fluorescence spectroscopy and transmission electron microscope, and furthermore, their pH‐responsive behavior was studied by UV‐vis and dynamic light scattering. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 1478–1486     

A solution‐processible poly(p‐phenylene vinylene) without alkyl substitution: Introducing the cis‐vinylene segments in polymer chain for improved solubility,blue emission,and high efficiency

A soluble all‐aromatic poly(2,5‐diphenyl‐1,4‐phenylenevinylene) (2,5‐DP‐PPV) is synthesized by utilizing aromatic phosphonium and aldehyde monomers through Wittig reaction. The H¹ NMR and FTIR measurements indicate that over 50% content of cis‐vinylene units exist in polymer backbone. The diphenyl‐substituted benzaldehyde monomer plays an important role to enhance cis‐products (Z‐selectivity) in Wittig reactions. The twisted cis‐segments in polymer backbone reduce the interchain interactions and enhance the solubility of such all‐aromatic PPV derivative in common organic solvents. 2,5‐DP‐PPV exhibits good solubility in common organic solvents, such as tetrahydrofuran and chloroform. The polymer film exhibits a blue light emission (λ_max = 485 nm) and a very high photoluminescence efficiency of 78%. The cis‐trans photo isomerization of this polymer in solution and the impact on the optical properties are also investigated. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 5242–5250, 2008     

Synthesis and characterization of highly hindered and thermally stable poly(1,4‐spirobifluorenylenevinylene) derivative

A new poly(1,4‐spirobifluorenylenevinylene) having advantage PPV and spirobifluorene as new emissive family was synthesized. Compared with PPV derivatives that usually have a tolane bisbenzyl defect, the polymer has the defect free structure because of the steric hindrance of the asymmetric bulky spirobifluorenyl group. Compared with spirobifluorene derivatives that usually have a low solubility, the polymer has the good solubility in common organic solvents. The polymer was amorphous and showed high PL quantum efficiency and high thermal stability with high T_g. The PL emission peaks were shown at 480–490 nm in solution and film, respectively, which may represent the bluest emission peak reported for fully conjugated PPV derivatives. The study of thermal annealing of PL spectrum showed excimer formation inhibited. The thermal and optoelectronic properties of the polymer imply that it is a promising material for the PLED application. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 900–907, 2007.     

Fluorinated vinyl ether homopolymers and copolymers: Living cationic polymerization and temperature‐induced solubility transitions in various organic solvents including perfluoro solvents

Partially fluorinated poly(vinyl ether)s with C₄F₉ and C₆F₁₂H groups in the side chain were synthesized via living cationic polymerization in the presence of an added base in a fluorine‐containing solvent, dichloropentafluoropropanes. For comparison, the polymerization of vinyl ether monomers with C₂F₅ and C₆F₁₃ groups and nonfluorinated monomers were also carried out. The characterization of the product polymers using size exclusion chromatography with a fluorinated solvent as an eluent indicated that all polymers had narrow molecular weight distributions (M_w/M_n ～ 1.1). Interestingly, the moderately fluorinated polymers with C₄F₉ exhibited upper critical solution temperature‐type phase separation in various organic solvents with wide‐ranging polarities, whereas highly fluorinated polymers with C₆F₁₃ are insoluble in nonfluorinated solvents. Polymers with C₄F₉ groups exhibited temperature dependent solubility transitions not only in common organic solvents (e.g., toluene, chloroform, tetrahydrofuran, and acetone) but also in perfluoro solvents [e.g., perfluoro(methylcyclohexane) and perfluorodecalin]. On the other hand, the solubility of polymers with C₆F₁₂H showed completely different from that of polymers with C₆F₁₃, despite their similar fluorine content. In addition, various types of fluorinated block copolymers were prepared in a living manner. The block copolymers with a thermosensitive fluorinated segment underwent temperature‐induced micellization and sol–gel transition in various organic solvents. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011     

Synthesis and properties of the ionomer diblock copolymer poly(4‐vinylbenzyl triethyl ammonium bromide)‐b‐polyisobutene

A new amphiphilic diblock copolymer containing an ionomer segment, poly[(4‐vinylbenzyl triethyl ammonium bromide)‐co‐(4‐methylstyrene)‐co‐(4‐bromomethylstyrene)]‐b‐polyisobutene [poly(4‐VBTEAB)‐b‐PIB], was synthesized by the chemical modification of poly(4‐methylstyrene)‐b‐polyisobutene [poly(4‐MSt)‐b‐PIB]. First, the 4‐methylstyrene moiety in poly(4‐MSt)‐b‐PIB was brominated with azobisisobutyronitrile as an initiator at 60 °C in CCl₄, and then the highly reactive benzyl bromide groups were ionized by a reaction with triethylamine in a toluene/isopropyl alcohol (80/20 v/v) mixture at about 85 °C to produce the ionomer diblock copolymer poly(4‐VBTEAB)‐b‐PIB. The solubility of the ionomer block copolymer was quite different from that of the corresponding poly[(4‐methylstyrene)‐co‐(4‐bromomethylstyrene)]‐b‐polyisobutene {poly[(4‐MSt)‐co‐(4‐BrMSt)]‐b‐PIB}. Transmission electron microscopy observations demonstrated that all three diblock copolymers had microphase‐separation structures in which polyisobutene (PIB) domains existed in the continuous phase of the poly(4‐methylstyrene) segment or its derivative segment matrix. Dynamic mechanical thermal analysis measurements showed that poly[(4‐MSt)‐co‐(4‐BrMSt)]‐b‐PIB had two glass‐transition temperatures (T_g's), ?56 °C for the PIB segment and 62 °C for the poly[(4‐MSt)‐co‐(4‐BrMSt)] domain, whereas poly(4‐VBTEAB)‐b‐PIB showed one T_g at ?8 °C of the PIB domain; T_g of the poly[(4‐vinylbenzyl triethyl ammonium bromide)‐co‐(4‐methylstyrene)‐co‐(4‐bromomethylstyrene)] domain was not observable because of the strong ionic interactions resulting in a higher T_g and a retention of modulus up to 124 °C. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 2755–2764, 2003     

Organoiron polynorbornenes with pendent arylazo and hetarylazo dye moieties

Organoiron polynorbornene containing arylazo or hetarylazo dye chromophores has been prepared via ring opening metathesis polymerization using Grubbs' catalyst. The obtained polymers were isolated as brightly colored materials and displayed good solubility in polar organic solvents. The colors of these polymers were affected by the nature of the incorporated azo chromophores. Thermogravimetric analysis of these materials showed that the cleavage of the cyclopentadienyliron (CpFe⁺) moieties was between 225 and 231 °C, while the degradation of the polymer backbones occurred between 400 and 450 °C. UV-vis studies in DMF showed that the organoiron polymers containing arylazo dyes exhibit wavelength maxima around 425 nm. However, the replacement of these arylazo moieties with hetarylazo dyes displayed substantial bathochromic shifts in the λ_max values (≈ 511 nm).