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Nogueira SL, Santos Silva H, Lère-Porte JP, Serein-Spirau F, Jarrosson T, Tozoni JR, Marletta A, Silva RA. Optical gap energy study of poly(thienylene-2,5-dialkoxyphenylene) in solid-state films. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2022; 272:120951. [PMID: 35131620 DOI: 10.1016/j.saa.2022.120951] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/25/2021] [Revised: 01/14/2022] [Accepted: 01/23/2022] [Indexed: 06/14/2023]
Abstract
Optical gap energy (Egap) in luminescent π-conjugated polymers presents several difficulties in its determination, particularly when using CW conventional optical spectroscopy, absorption and emission. This happens due to several physicochemical parameter's dependence. Among others, the molecular conformation, intramolecular interactions, structural defects, polymer processability and solvent interaction stand out. In addition, there is a distribution of conjugated segments along the polymeric main chains that differentiate optical absorption transition from emission processes. In other words, these processes do not necessarily occur in the same conjugated segment owing to the very efficient ratios of energy transfer or charge migration in these materials. In this work we present a systematic study of the determination of Egap for the polymer poly(thienylene-2,5-dialkoxyphenylene). We present a comparison between the solution and solid-state film, clearly showing the presence of a polymer-polymer interaction as aggregate species. The goal of this paper is to isolate and aggregate the contribution determination of each species through systematic analysis of optical spectra, as well as to obtain, even on film, the Egap of the isolated polymer which is very similar to the polymer solution at about 2.37 eV. The intersection theory and the voltammetry methods corroborate the experiment and the discussion of the results obtained.
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Affiliation(s)
- S L Nogueira
- Centro Universitário de Patos de Minas - UNIPAM, 31708-054 Patos de Minas, MG, Brazil; Instituto de Física, Universidade Federal de Uberlândia, MG, Brasil.
| | | | - J P Lère-Porte
- Institut Charles Gerhardt, Equipe AM(2)N - Architectures Moléculaires et Matériaux Nanostructurés. ENSCM, Montpellier - France
| | - F Serein-Spirau
- Institut Charles Gerhardt, Equipe AM(2)N - Architectures Moléculaires et Matériaux Nanostructurés. ENSCM, Montpellier - France
| | - T Jarrosson
- Institut Charles Gerhardt, Equipe AM(2)N - Architectures Moléculaires et Matériaux Nanostructurés. ENSCM, Montpellier - France
| | - J R Tozoni
- Instituto de Física, Universidade Federal de Uberlândia, MG, Brasil
| | - A Marletta
- Instituto de Física, Universidade Federal de Uberlândia, MG, Brasil
| | - R A Silva
- Instituto de Física, Universidade Federal de Uberlândia, MG, Brasil
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van Riel Neto F, Foschini M, Tozoni JR, Piovesan E, Cristovan FH, Marletta A. Optical spectroscopy study of the interaction between curcumin and acrylic polymers. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2021; 260:119954. [PMID: 34051635 DOI: 10.1016/j.saa.2021.119954] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Revised: 05/06/2021] [Accepted: 05/09/2021] [Indexed: 06/12/2023]
Abstract
This paper presents the results of a study conducted on the interaction between curcumin, a compound with several biomedical applications in traditional and modern medicine, and the acrylic polymers poly(methyl methacrylate), poly(ethyl methacrylate), and poly(n-butyl methacrylate), through photophysical experiments in curcumin/acrylic polymers casting films. Optical absorption intensity at ~340 nm increases relatively to its maximum at ~417 nm when the amount of curcumin in the polymeric film decreases, due to a significant change in the concentration of the isomers cis- or trans-form of curcumin, regardless of the acrylic polymer. Fluorescence (FL) spectra of the films depend on the curcumin concentration in the matrix with well-resolved line shape. They show two distinct bands, one at ~525 nm, for higher curcumin concentration (5.00 mmol.L-1), related to the aggregated curcumin species, and another at ~465 nm, for lower concentration of curcumin (0.10 mmol.L-1), related to the effects of the solvent on the conformational structure of the curcumin molecule and the presence of the trans-form of curcumin. The parameter Kagg, related to the contribution of the aggregated curcumin, shows the influence of the polymeric lateral chain length of the matrix in the de-aggregation of the curcumin. The Huang-Rhys factor indicates that curcumin aggregated species are conformationally more stable, and that the isolate species depends on the chemical environment and the matrix/curcumin interaction, decreasing its conformational degrees of freedom. Arrhenius plots, obtained via FL experiment in function of the sample temperature, show that, for higher curcumin concentration, the value for the relaxation energy process is not well defined, due the decrease in the interaction between the matrix and the curcumin molecules. With these results, it is possible to infer that the interaction matrix/curcumin must occur via lateral chemical alkyl groups.
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Affiliation(s)
| | - Maurício Foschini
- Institute of Physics - Federal University of Uberlândia, CP 593, 38400-902 Uberlândia-MG, Brazil.
| | - José Roberto Tozoni
- Institute of Physics - Federal University of Uberlândia, CP 593, 38400-902 Uberlândia-MG, Brazil.
| | - Erick Piovesan
- Institute of Physics - Federal University of Uberlândia, CP 593, 38400-902 Uberlândia-MG, Brazil.
| | | | - Alexandre Marletta
- Institute of Physics - Federal University of Uberlândia, CP 593, 38400-902 Uberlândia-MG, Brazil.
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Bertoldo Menezes D, Reyer A, Benisek A, Dachs E, Pruner C, Musso M. Raman spectroscopic insights into the glass transition of poly(methyl methacrylate). Phys Chem Chem Phys 2021; 23:1649-1665. [PMID: 33411861 DOI: 10.1039/d0cp05627h] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Poly(methyl methacrylate) (PMMA) is a very versatile polymer which is used as a glass substitute or as an economical alternative to polycarbonate for many types of important applications, due to its particular physical properties. In this study we deal with the Raman spectroscopic characterization of the glass transition of PMMA, the value of the glass transition temperature being generally a decisive parameter for determining the application of polymers. The information obtained by two-dimensional correlation spectroscopy (2DCOS) analysis and perturbation-correlation moving-windows spectroscopy (PCMW2D) analysis of the temperature dependent depolarized Raman spectra enabled us to recognize that the glass transition of PMMA is ruled by intermolecular interactions which influence the vibrational modes of the molecular groups associated with ν(C[double bond, length as m-dash]O), δa(C-H) of α-CH3 and/or O-CH3, ν(C-O-C), ν(C-COO), and ν(C-C-O). This information was employed for the temperature dependent study of the Raman shift and of the full width at half maximum of the Raman peaks obtained through anisotropic and isotropic Raman spectra, of the depolarization ratio, of the Raman spectroscopic noncoincidence effect, and of the Raman peak intensities represented by Arrhenius-type plots, all results supporting the outcomes of this work. The comparison with results obtained by differential scanning calorimetry and with published results in molecular dynamics studies was also part of this work. As the main result, one can highlight the peak associated with the ν(C-O-C) stretching mode at around 812 cm-1 as the one which presents the better outcome for explaining the glass transition from the molecular point of view.
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Affiliation(s)
- D Bertoldo Menezes
- Federal Institute of Triângulo Mineiro, 1020, 38400-970, Uberlândia, Minas Gerais, Brazil. and Department of Chemistry and Physics of Materials, University of Salzburg, Jakob-Haringer-Strasse 2a, 5020, Salzburg, Austria
| | - A Reyer
- Department of Chemistry and Physics of Materials, University of Salzburg, Jakob-Haringer-Strasse 2a, 5020, Salzburg, Austria
| | - A Benisek
- Department of Chemistry and Physics of Materials, University of Salzburg, Jakob-Haringer-Strasse 2a, 5020, Salzburg, Austria
| | - E Dachs
- Department of Chemistry and Physics of Materials, University of Salzburg, Jakob-Haringer-Strasse 2a, 5020, Salzburg, Austria
| | - C Pruner
- Department of Chemistry and Physics of Materials, University of Salzburg, Jakob-Haringer-Strasse 2a, 5020, Salzburg, Austria
| | - M Musso
- Department of Chemistry and Physics of Materials, University of Salzburg, Jakob-Haringer-Strasse 2a, 5020, Salzburg, Austria
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de Fátima Curcino da Silva S, Turchetti DA, Therézio EM, Tozoni JR, Akcelrud L, Marletta A. Temperature effect on the electron–vibrational mode coupling of a fully conjugated polyfluorene derivative. Phys Chem Chem Phys 2019; 21:16779-16784. [DOI: 10.1039/c9cp02814e] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The electron–vibrational mode coupling, Huang–Rhys parameter and polymer relaxations were directly correlated and used to explain the differences in the EL and PL processes.
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Affiliation(s)
| | | | - Eralci M. Therézio
- Physics Institute
- Federal University of Mato Grosso
- Cuiabá
- Brazil
- Institute of Exact and Natural Sciences
| | | | - Leni Akcelrud
- Paulo Scarpa Polymer Laboratory (LaPPS) Federal University of Parana
- Curitiba
- Brazil
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Bertoldo Menezes D, Reyer A, Musso M. Investigation of the Brill transition in nylon 6,6 by Raman, THz-Raman, and two-dimensional correlation spectroscopy. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2018; 190:433-441. [PMID: 28961527 DOI: 10.1016/j.saa.2017.09.055] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/09/2017] [Revised: 09/19/2017] [Accepted: 09/19/2017] [Indexed: 06/07/2023]
Abstract
The Brill transition is a phase transition process in polyamides related with structural changes between the hydrogen bonds of the lateral functional groups (CO) and (NH). In this study, we have used the potential of Raman spectroscopy for exploring this phase transition in polyamide 6,6 (nylon 6,6), due to the sensitivity of this spectroscopic technique to small intermolecular changes affecting vibrational properties of relevant functional groups. During a step by step heating and cooling process of the sample we collected Raman spectra allowing us from two-dimensional Raman correlation spectroscopy to identify which spectral regions suffered the largest influence during the Brill transition, and from Terahertz Stokes and anti-Stokes Raman spectroscopy to obtain complementary information, e.g. on the temperature of the sample. This allowed us to grasp signatures of the Brill transition from peak parameters of vibrational modes associated with (CC) skeletal stretches and (CNH) bending, and to verify the Brill transition temperature at around 160°C, as well as the reversibility of this phase transition.
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Affiliation(s)
- D Bertoldo Menezes
- Federal Institute of the Triângulo Mineiro, Mailbox: 1020, Zip Code 38400-970, Uberlândia, Minas Gerais, Brazil; Department of Chemistry and Physics of Materials, University of Salzburg, Jakob-Haringer-Strasse 2a, 5020 Salzburg, Austria.
| | - A Reyer
- Department of Chemistry and Physics of Materials, University of Salzburg, Jakob-Haringer-Strasse 2a, 5020 Salzburg, Austria
| | - M Musso
- Department of Chemistry and Physics of Materials, University of Salzburg, Jakob-Haringer-Strasse 2a, 5020 Salzburg, Austria
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Bertoldo Menezes D, Reyer A, Marletta A, Musso M. Determination of the temperatures of the γ, β and α relaxation processes in nylon 6,6 by Raman spectroscopy. POLYMER 2016. [DOI: 10.1016/j.polymer.2016.10.058] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Tozoni J, Neto NB, Ribeiro C, Pazin W, Ito A, Borissevitch I, Marletta A. Relationship between porphyrin aggregation and formation of porphyrin ring structures in poly(n-alkyl methacrylate)/porphyrin blends. POLYMER 2016. [DOI: 10.1016/j.polymer.2016.09.009] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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