Quantifying the Level of Intermacromolecular Interactions in Ethylene–Propylene Copolymers by Using Pyrene Excimer Formation

Pirouz, Solmaz; Duhamel, Jean; Sheng, Jiang; Duggal, Akhilesh

doi:10.1021/acs.macromol.5b00806

Cited by 8 publications

(42 citation statements)

References 31 publications

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“…As for EP(80) in Figure , this behavior was attributed to the formation of crystalline microdomains by EP(78) in toluene that would lead to an enhancement of [ Py ] loc and thus of the I E / I M ratio. This feature of the I E / I M ‐vs‐ T profiles seems to be common for semicrystalline polymers randomly labeled with pyrene …”

Section: Characterization Of Polymeric Oil Additives By Pefmentioning

confidence: 66%

“…The four I E / I M ‐vs‐ T profiles shown in Figure were processed according to eq to yield plots of f inter as a function of temperature for the two PMA‐EP(60) and PMA‐EP(78) samples at a polymer concentration of 10 g L −1 . Similar experiments were conducted for the same Py‐EP copolymers at a polymer concentration of 10 mg L −1 and the corresponding f inter values were also included in Figure . Contrary to the complex behavior of the I E / I M trends observed in Figure , the f inter ‐vs‐ T profiles shown in Figure could be readily interpreted.…”

Section: Characterization Of Polymeric Oil Additives By Pefmentioning

confidence: 80%

“…For such semicrystalline EP copolymers, the formation of microcrystals at lower solution temperature would indicate a worsening of the solvent quality toward the polymer which would be accompanied by an increase in intermolecular interactions. Since such associations would lead to the formation of polymer aggregates that would affect the viscosity of the solution, Pirouz et al investigated whether pyrene excimer fluorescence could be applied to measure quantitatively the molar fraction ( f inter ) of intermolecular interactions taking place in solution …”

Section: Characterization Of Polymeric Oil Additives By Pefmentioning

confidence: 99%

“…(B) (▵) PMA‐EP(60) (10 g L −1 ), (□) mixture of PMA‐EP(60) (0.01 g L −1 ), and EP(60) (10 g L −1 ). Solvent = toluene . Reprinted (adapted) with permission from (S. Pirouz, J. Duhamel, S. Jiang, A. Duggal.…”

Section: Characterization Of Polymeric Oil Additives By Pefmentioning

confidence: 99%

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New approaches to characterize polymeric oil additives in solution based on pyrene excimer fluorescence

Pirouz¹,

Duhamel²

2016

J. Polym. Sci. Part B: Polym. Phys.

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Maleated polyolefins (MaPOs) such as maleated ethylene propylene copolymers or polyisobutylene terminated at one end with a succininic anhydride can be used as polymeric dispersants in engine oils after reaction with polyamines while unmodified EP copolymers improve the viscosity index of oils. MaPOs can also be labeled with pyrene derivatives to generate pyrene-labeled polyolefins (PyLPOs) as fluorescent mimics of oil additives and pyrene excimer fluorescence (PEF) can be applied to probe their behavior in solution. This review describes new methodology that was recently implemented to characterize the complex fluorescence signal emitted by PyLPOs by using steady-state and time-resolved fluorescence. This methodology enables one to gain quantitative information about the level of clustering of the succinic pendants along a maleated polyolefins and intra-and intermolecular aggregation of polyolefins in solution. Such information is relevant to scientists aiming to characterize polymeric oil additives used in engine oil.

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Section: Characterization Of Polymeric Oil Additives By Pefmentioning

confidence: 66%

Section: Characterization Of Polymeric Oil Additives By Pefmentioning

confidence: 80%

Section: Characterization Of Polymeric Oil Additives By Pefmentioning

confidence: 99%

Section: Characterization Of Polymeric Oil Additives By Pefmentioning

confidence: 99%

See 2 more Smart Citations

New approaches to characterize polymeric oil additives in solution based on pyrene excimer fluorescence

Pirouz¹,

Duhamel²

2016

J. Polym. Sci. Part B: Polym. Phys.

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“…Huser et al 50 studied the several types of aggregates in films cast from solutions of distinct solvents, which are the reason for the multicolored fluorescence they observed. Also, Duhamel et al [51][52][53][54] demonstrated that intermolecular interactions can be quantitatively described by steady-state and time-resolved fluorescence spectroscopy, since the distinct aggregates present distinct photophysics. Vol.…”

mentioning

confidence: 99%

Photoluminescence of Solvent-Selected Fluorescent Moieties in MEH-PPV Solutions and Films

Ribeiro¹,

Camargo²,

Pereira³

et al. 2017

J. Braz. Chem. Soc.

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In this work, we examined how photoluminescence in poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene] (MEH-PPV) is affected by morphology, dictated by the mode of preparation. For that, MEH-PPV dilute solutions in good and non-solvents, thick cast films with poly[methylmethacrylate] (PMMA) as inert matrix and spin-coated thin films were prepared. These systems were studied by steady-state and time-dependent fluorescence spectroscopy and electronic microscopy. Unexpected photoluminescent behavior was detected in solutions and films and it was related to different excitons modulated by MEH-PPV conformation. By semi empirical calculations we obtained the singlet and triplet state energies of an MEH-PPV model system and, from time-resolved fluorescence spectroscopy, the existence of short-lived excited states was revealed, enabling us to infer on possible singlet fission in MEH-PPV-based systems.Keywords: photoluminescence, morphology, thin films, time-resolved fluorescence, computational calculations IntroductionSince poly(phenylene-vinylene) (PPV) derivatives were found to be electroluminescent, 1 the search for a systematic method to determine their applications has been of great interest. Their mechanical, morphological and optical properties have been widely discussed and findings related these properties to preparation methods. Although there are many aspects regarding the effects of preparation methods on optical response, authors seem to agree that preparation method influences molecular conformation, enabling or inhibiting aggregation and, consequently, affecting inter and intrachain interactions. Processing parameters are believed to modify the conformation and assembling mechanisms of polymeric materials, resulting in a memory effect of the structural information that is replicated from solutions to solid films. Therefore, to understand the role of chain conformation in solution is of major importance for applications such as device fabrication, since properties can be tuned, enhancing the desired characteristics and suppressing the undesired ones. 2,3 For instance, it is well known that photoluminescence of PPV derivatives show prominent red-shift due to the enhancement of energy transfer as the π-electron delocalization increases. 4 As pointed out in an earlier work, 5 this red-shift indicates aggregation driven by π-π interactions as the conjugation length increases.In polymeric systems, several occurrences are responsible for chain torsions that impose limits to the length of conjugated segments, affecting the highest occupied molecular orbital (HOMO)-lowest unoccupied molecular orbital (LUMO) energy gaps. They are interpreted as stabilization and/or destabilization of HOMO and LUMO levels. 6 These occurrences may be related to the presence of impurities, molecules of solvent that strongly interact with the polymer chains and a distribution of torsion angles promoted by molecular interactions of any nature. 6 In this situation, the densities of excited states (DOS) available for electronic chan...

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End Group Analysis of Polyisobutylene Succinic Anhydride (PIBSA) Carried Out with Pyrene Excimer Fluorescence

Frasca

Duhamel

2022

Ind. Eng. Chem. Res.

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A procedure is established to determine the molar fraction (f doubly) of doubly-maleated polyisobutylene (PIBSA2) in a PIBSA sample mainly constituted of mono-maleated polyisobutylene (PIBSA1), where the succinic anhydride (SA) groups are located at the end of the PIB chain. To this end, a PIBSA sample was labeled with 1-pyrenemethylamine (PyMA) to generate PIB-PySI, where the 1-pyrenemethyl group was linked to the PIB chain via a succinimide group. Depending on the procedure applied to purify the PIB-PySI samples, different regions of the molecular weight distribution (MWD) representing the PIBSA samples could be isolated and characterized by a combination of GPC, FTIR, and UV–vis absorption analysis to yield its MWD, number of isobutylene units per succinic anhydride (N IB/N SA), and pyrene content (λPy, in μmol of pyrene per gram of sample). These analyses were consistent with the expected size and chemical composition of the different PIB-PySI samples. f doubly was calculated from the molar fraction (f agg) of pyrene labels attached onto the PIBSA2 species. f agg was determined through the global model free analysis (MFA) of the fluorescence decays of the pyrene monomer and excimer acquired for solutions of the PIB-PySI samples in THF. The different fractions of the MWD of the PIBSA sample yielded similar f doubly values across the MWD, implying an even distribution of PIBSA2 species across a PIBSA MWD. The constancy of f doubly across the MWD enabled the determination of the number average molecular weight (M n ) of the PIB-PySI samples from λPy. An analysis combining the GPC traces obtained with a differential refractive index and UV–vis absorption detector yielded the MWD of the original PIBSA sample. These experiments demonstrated that the proposed PEF-based methodology can be applied to characterize the SA end groups of PIBSA samples and could be further extended to characterize the end groups of other end-functionalized polymers.

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Quantifying the Level of Intermacromolecular Interactions in Ethylene–Propylene Copolymers by Using Pyrene Excimer Formation

Cited by 8 publications

References 31 publications

New approaches to characterize polymeric oil additives in solution based on pyrene excimer fluorescence

New approaches to characterize polymeric oil additives in solution based on pyrene excimer fluorescence

Photoluminescence of Solvent-Selected Fluorescent Moieties in MEH-PPV Solutions and Films

End Group Analysis of Polyisobutylene Succinic Anhydride (PIBSA) Carried Out with Pyrene Excimer Fluorescence

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