Intramolecular Excited-State Processes of a Halato-Telechelic Polymer, Evaluated by Global Compartmental Analysis of the Fluorescence Decay Surface with the Use of Model Compounds

Stam, Jan van; Schryver, F. C. De; Boens, Noël; Hermans, Bart; Jérôme, Robert; Trossaert, Geert; Goethals, E.; Schacht, Etienne

doi:10.1021/ma961271q

Cited by 3 publications

(2 citation statements)

References 78 publications

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“…To our knowledge, it is the first time that this type of quantitative analysis is carried out for a system presenting such a high level of polydispersity: The polymer chains are polydisperse in length ( M w / M n = 1.6), the polymer aggregates are polydisperse in size, and the distance between two labels are polydisperse as well, due to the random pyrene labeling of the polymer. The inherent polydispersity of the system makes it somewhat difficult to apply the global compartmental analysis method which has been developed so far for well-characterized systems …”

Section: Introductionmentioning

confidence: 99%

Study of a Polymeric Network by Dynamic Fluorescence Quenching Using a Blob Model

Vangani¹,

Duhamel²,

Németh³

et al. 1999

Macromolecules

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The association behavior of a maleic anhydride grafted and pyrene labeled ethylenepropylene random copolymer was studied using fluorescence spectroscopy. The labeling was achieved with 1-pyrenebutanoic acid hydrazide via the grafted anhydride groups. The resulting polar grafts induced intra-and intermolecular associations among the polymer chains in apolar solvents. This association process was studied using steady-state and time-resolved fluorescence spectroscopy as a function of polymer concentration. Due to the high complexity of the polymer system, an improved approach of handling the time-resolved fluorescence data had to be introduced. Thus, the quantitative analysis of the fluorescence decays was carried out using a novel model in which the polymer network is divided into blobs among which the chromophores distribute themselves randomly, according to a Poisson distribution. Results show that, as the polymer concentration is increased, the number of polar group aggregates increases. However, the local concentration of aggregated polar groups in the polymer network does not change. This indicates that as polymer concentration is increased, either that there are only a few polymer aggregates in the solution that increase in size and keep the concentration of polar junctions constant throughout the polymeric network or that more polymer aggregates are formed. This latter process would be reminiscent of micelle formation. This behavior is observed until the overlap concentration (c* ) 10-20 g/L), above which newly formed polar aggregates contribute to increasing the local aggregate concentration.

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Section: Introductionmentioning

confidence: 99%

Study of a Polymeric Network by Dynamic Fluorescence Quenching Using a Blob Model

Vangani¹,

Duhamel²,

Németh³

et al. 1999

Macromolecules

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“…The low concentration of MeBIP ligand in a polymer sample favors intramolecular interactions over intermolecular metal–ligand bond formation during the supramolecular polymerization, which converts the prepolymers to free-standing, network films (Figure ). − The bound MeBIP ligands should complex with another bound MeBIP ligand on the same prepolymer chain due to nearest-neighbor effects in solution. The resulting intramolecular interactions constrain the prepolymer into a cyclic topology rather than typical cross-linked networks (Figure , route 2).…”

Section: Results and Discussionmentioning

confidence: 99%

Tuning the Morphology of an Acrylate-Based Metallo-Supramolecular Network: From Vesicles to Cylinders

et al. 2018

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This work investigated the morphological behavior of an acrylate-based metallo-supramolecular polymer system. RAFT (reversible addition–fragmentation chain transfer) polymerization techniques were used to synthesize low molar mass, linear prepolymers of n-butyl acrylate and a 2,6-bis(1′-methylbenzimidazolyl)pyridine–acrylate monomer (MeBIP–Ac) of varying concentration (2–10%). This synthesis incorporated a systematic increase of cross-link points (MeBIP ligands) pendent to the polymer backbone. A zinc(II) salt (Zn(ClO4)2) complexed with the pendent MeBIP ligands in a 1:2 ratio to form cross-linked polymers as free-standing films. The morphology of the neat films as well as those with added unbound MeBIP–zinc–MeBIP metal–ligand (ML) complex were characterized using transmission electron microscopy (TEM), HAADF-STEM (high angle annular dark field scanning transmission electron microscopy), energy dispersive X-ray spectroscopy (EDS), electron energy loss spectroscopy (EELS), energy-filtered TEM (EFTEM), and small-angle X-ray scattering (SAXS) techniques. A vesicle morphology in the bulk material was found for films of the neat polymer containing 2% MeBIP, while films at all other compositions exhibited a disordered microphase-separated morphology. The vesicle morphology of the 2% MeBIP films was transformed into a morphology of cylinders with the addition of unbound MeBIP–zinc–MeBIP complex.

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Effect of Aromatic Ring Substitution on the Optical Properties, Emission Dynamics, and Solid-State Behavior of Fluorinated Oligophenylenevinylenes

et al. 1999

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Several substituted oligophenylenevinylenes were synthesized using the Wittig−Horner−Emmons reaction to produce the trans isomers. Optical properties of these compounds were evaluated using absorption and steady-state fluorescence spectroscopy. Fluorescence quantum yields, Φf, decrease with increasing solvent polarity and approach unity in nonpolar solvents in the case of substituted trans,trans-1,4-bis[2-(2‘,5‘-difluoro)phenylethenyl]benzenes and trans,trans-1,4-bis[2-(2‘,5‘-dialkoxy)phenylethenyl)-2,3,5,6-tetrafluorobenzenes. The compounds show a strong solvatochromic shift as a function of solvent polarity, yielding a slope of −13 300 cm- 1 according to the Lippert−Mataga equation and indicating the emission of an additional charge-transfer species. A two-state reaction model was confirmed for trans,trans-1,4-bis[2-(2‘,5‘-dialkoxy)phenylethenyl)-2,3,5,6-tetrafluorobenzene (6d) in different solvents by time-correlated single-photon counting using global analysis. A dependence of the kinetic data on solvent polarity was found (global fitted decay times in picoseconds for τ1 and τ2: 381/1281 in n-hexane; 101/1590 in toluene; 27/2974 in acetonitrile). Investigations of the solid state showed liquid crystalline behavior for 6d and for trans,trans-1,4-bis[2-(2‘,5‘-difluoro)phenylethenyl]-2,5-diheptyloxybenzene (3b). This was confirmed by polarization microscopy and thermal analysis. Both the long alkoxy chains and fluorine substitution are responsible for the formation of mesophases. Photoluminescence studies of 3b and 6d in the solid state indicated an intense emission that was yellow for 3b.

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Intramolecular Excited-State Processes of a Halato-Telechelic Polymer, Evaluated by Global Compartmental Analysis of the Fluorescence Decay Surface with the Use of Model Compounds

Cited by 3 publications

References 78 publications

Study of a Polymeric Network by Dynamic Fluorescence Quenching Using a Blob Model

Study of a Polymeric Network by Dynamic Fluorescence Quenching Using a Blob Model

Tuning the Morphology of an Acrylate-Based Metallo-Supramolecular Network: From Vesicles to Cylinders

Effect of Aromatic Ring Substitution on the Optical Properties, Emission Dynamics, and Solid-State Behavior of Fluorinated Oligophenylenevinylenes

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