scholarly journals Conformation of Pyrene-Labeled Amylose in DMSO Characterized with the Fluorescence Blob Model

2016 ◽  
Vol 49 (20) ◽  
pp. 7965-7974 ◽  
Author(s):  
Lu Li ◽  
Jean Duhamel
Keyword(s):  
Blob Model

Seeking the Good Fitting Procedure of PALS Polymer Spectra

2008 ◽  
Vol 607 ◽  
pp. 64-66
Author(s):  
Nicolas Laforest ◽  
Jérémie De Baerdemaeker ◽  
Corine Bas ◽  
Charles Dauwe
Keyword(s):  
Experimental Data ◽  
Low Temperature ◽  
Positron Annihilation ◽  
Physical Meaning ◽  
Lifetime Measurements ◽  
Positron Annihilation Lifetime ◽  
Fitting Procedure ◽  
Fitting Procedures ◽  
Blob Model

Positron annihilation lifetime measurements on polymethylmethacrylate (PMMA) at low temperature were performed. Different discrete fitting procedures have been used to analyze the experimental data. It shows that the extracted parameters depend strongly on the fitting procedure. The physical meaning of the results is discussed. The blob model seems to give the best annihilation parameters.

How switching the substituent of a pyrene derivative from a methyl to a butyl affects the fluorescence response of polystyrene randomly labeled with pyrene

2010 ◽  
Vol 88 (3) ◽  
pp. 217-227 ◽  
Author(s):  
Mark Ingratta ◽  
Manoj Mathew ◽  
Jean Duhamel
Keyword(s):  
Organic Solvents ◽  
Excellent Agreement ◽  
Fluorescence Spectra ◽  
Series Solutions ◽  
Specific Nature ◽  
Polymer Backbone ◽  
Excimer Fluorescence ◽  
Fluorescence Response ◽  
Different Types ◽  
Blob Model

A series of polystyrenes randomly labeled with 1-pyrenebutanol were prepared by copolymerizing styrene and 1-pyrenebutylacrylate yielding the CoBuE–PS series. Solutions of CoBuE–PS were prepared in nine organic solvents having viscosities ranging from 0.36 to 5.5 mPa·s and the fluorescence spectra and pyrene monomer and excimer fluorescence decays were acquired. Analysis of the fluorescence spectra yielded the IE/IM ratio, whereas analysis of the fluorescence decays with the fluorescence blob model (FBM) yielded the parameters N blobo , <kblob × Nblob> , and k blobo . These parameters were compared to those obtained with two other series of pyrene-labeled polystyrenes, which had been studied earlier, namely CoA–PS and CoE–PS where pyrene was attached to the polymer backbone via a methylamide and benzyl methylether linker, respectively. Although the parameters IE/IM, N blobo , <kblob × Nblob>, and k blobo took different values according to the specific nature of the linker connecting pyrene to the polystyrene backbone, they exhibited trends that were quite similar for all the pyrene-labeled polystyrene constructs. The excellent agreement between the parameters retrieved for the three different types of pyrene-labeled polystyrenes suggests that the FBM accounts satisfyingly for differences in the nature of the label used, while still retrieving information pertinent to the polymer of interest.

scholarly journals Unfolding of Helical Poly(L-Glutamic Acid) in N,N-Dimethylformamide Probed by Pyrene Excimer Fluorescence (PEF)

Polymers ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1690
Author(s):  
Weize Yuan ◽  
Remi Casier ◽  
Jean Duhamel
Keyword(s):  
Glutamic Acid ◽  
Local Density ◽  
Guanidine Hydrochloride ◽  
Racemic Mixture ◽  
Excimer Fluorescence ◽  
Excimer Formation ◽  
Blob Model ◽  
Α Helix ◽  
The Relationship ◽  
Pyrene Excimer Formation

The denaturation undergone by α–helical poly(L-glutamic acid) (PLGA) in N,N-dimethylformamide upon addition of guanidine hydrochloride (GdHCl) was characterized by comparing the fluorescence of a series of PLGA constructs randomly labeled with the dye pyrene (Py-PLGA) to that of a series of Py-PDLGA samples prepared from a racemic mixture of D,L-glutamic acid. The process of pyrene excimer formation (PEF) was taken advantage of to probe changes in the conformation of α–helical Py-PLGA. Fluorescence Blob Model (FBM) analysis of the fluorescence decays of the Py-PLGA and Py-PDLGA constructs yielded the average number (<Nblob>) of glutamic acids located inside a blob, which represented the volume probed by an excited pyrenyl label. <Nblob> remained constant for randomly coiled Py-PDLGA but decreased from ~20 to ~10 glutamic acids for the Py-PLGA samples as GdHCl was added to the solution. The decrease in <Nblob> reflected the decrease in the local density of PLGA as the α–helix unraveled in solution. The changes in <Nblob> with GdHCl concentration was used to determine the change in Gibbs energy required to denature the PLGA α–helix in DMF. The relationship between <Nblob> and the local density of macromolecules can now be applied to characterize the conformation of macromolecules in solution.

An approach to the theta temperature of star polymers based on the blob model

Polymer ◽  
1997 ◽  
Vol 38 (25) ◽  
pp. 6255-6258 ◽  
Author(s):  
Anastasios Dondos ◽  
Dimitrios Papanagopoulos
Keyword(s):  
Star Polymers ◽  
Theta Temperature ◽  
Blob Model

A blob model to parameterize polymer hole free volumes and solute diffusion

Soft Matter ◽  
2019 ◽  
Vol 15 (43) ◽  
pp. 8912-8932 ◽  
Author(s):  
Yan Zhu ◽  
Frank Welle ◽  
Olivier Vitrac
Keyword(s):  
Free Volume ◽  
Solute Diffusion ◽  
Solid Polymers ◽  
Blob Model

Solute diffusion in solid polymers has tremendous applications but remained poorly understood: (i) general solute blob model, (ii) hole-free volume parameterization and diffusivity D model, (iii) example of parameterization and D predictions in PET.

A blob model to study polymer chain dynamics in solution

1993 ◽  
Vol 97 (51) ◽  
pp. 13708-13712 ◽  
Author(s):  
Jean Duhamel ◽  
Ahmad Yekta ◽  
Mitchell A. Winnik ◽  
Tze Chi Jao ◽  
Munmaya K. Mishra ◽  
...  
Keyword(s):  
Polymer Chain ◽  
Chain Dynamics ◽  
Blob Model
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