Rouse dynamics in PEO-PPO-PEO block-copolymers in aqueous solution as observed through fast field-cycling NMR relaxometry

Fraenza, Carla Cecilia; Mattea, Carlos; Farrher, Germán; Ordikhani-Seyedlar, Amín; Stapf, Siegfried; Anoardo, Esteban

doi:10.1016/j.polymer.2018.07.027

Cited by 10 publications

(14 citation statements)

References 58 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The blocks can be arranged in two (A-B-type diblock copolymers) or three alternating segments (A-B-A-type triblock copolymers) and their chain lengths, ratio and overall MW determine the size and morphology of BCMs. Owing to their dynamic properties as relatively small fast tumbling systems with a high degree of internal motional freedom of the flexible polymer chains [ 221 ], BCMs are very well applicable for NMR spectroscopic characterizations giving rise to intense 1 H NMR resonances in aqueous solution ( Figure 6 ). The micelle formation process from block copolymer unimers induces changes not just in the diffusion properties but also in the 1 H- and 13 C-chemical shifts, resonance linewidths and relaxation rates of the polymeric nuclei rendering NMR a suitable method to monitor micellization [ 222 , 223 , 224 , 225 , 226 ].…”

Section: Applications To Study Porphyrin–macromolecule Interactionmentioning

confidence: 99%

Probing the Interactions of Porphyrins with Macromolecules Using NMR Spectroscopy Techniques

2021

View full text Add to dashboard Cite

Porphyrinic compounds are widespread in nature and play key roles in biological processes such as oxygen transport in blood, enzymatic redox reactions or photosynthesis. In addition, both naturally derived as well as synthetic porphyrinic compounds are extensively explored for biomedical and technical applications such as photodynamic therapy (PDT) or photovoltaic systems, respectively. Their unique electronic structures and photophysical properties make this class of compounds so interesting for the multiple functions encountered. It is therefore not surprising that optical methods are typically the prevalent analytical tool applied in characterization and processes involving porphyrinic compounds. However, a wealth of complementary information can be obtained from NMR spectroscopic techniques. Based on the advantage of providing structural and dynamic information with atomic resolution simultaneously, NMR spectroscopy is a powerful method for studying molecular interactions between porphyrinic compounds and macromolecules. Such interactions are of special interest in medical applications of porphyrinic photosensitizers that are mostly combined with macromolecular carrier systems. The macromolecular surrounding typically stabilizes the encapsulated drug and may also modify its physical properties. Moreover, the interaction with macromolecular physiological components needs to be explored to understand and control mechanisms of action and therapeutic efficacy. This review focuses on such non-covalent interactions of porphyrinic drugs with synthetic polymers as well as with biomolecules such as phospholipids or proteins. A brief introduction into various NMR spectroscopic techniques is given including chemical shift perturbation methods, NOE enhancement spectroscopy, relaxation time measurements and diffusion-ordered spectroscopy. How these NMR tools are used to address porphyrin–macromolecule interactions with respect to their function in biomedical applications is the central point of the current review.

show abstract

Section: Applications To Study Porphyrin–macromolecule Interactionmentioning

confidence: 99%

Probing the Interactions of Porphyrins with Macromolecules Using NMR Spectroscopy Techniques

2021

View full text Add to dashboard Cite

show abstract

“…1 D 2 O was used in lieu of H 2 O to monitor the NMR response from copolymer protons only, while the protons of HDO molecules encounter a nondispersive relaxation rate behavior, as they pertain to the bulk water. 35 The isotropic and cubic phase systems were stored at ∼4 °C until homogeneous transparent solutions were obtained, while the hexagonal and lamellar phase samples possessing high viscosities were subjected to thermal cycling and thorough mixing to obtain homogeneous phases. Before a few hours of NMR measurements, the mixtures were transferred into NMR tubes.…”

Section: ■ Materials and Methodsmentioning

confidence: 99%

“…FFC NMR relaxation dispersions were recorded after equilibrating the samples at the required temperature for at least 4 h. The temperature stability was regulated within 0.1 °C, whereas the temperature gradient across the sample is expected to be within 0.2 °C. Our earlier studies on similar block copolymer solutions 35 determined a local field lower than 1 kHz using the fixed lock-time rotating frame dispersion experiment. 36 In this scenario, R 1 dispersions were recorded (present study) from a minimum Larmor frequency of 5 kHz to avoid any unwanted local field effects.…”

Section: ■ Materials and Methodsmentioning

confidence: 99%

“…36 In this scenario, R 1 dispersions were recorded (present study) from a minimum Larmor frequency of 5 kHz to avoid any unwanted local field effects. 35 Proton R 1 profiles were collected using both prepolarized and nonpolarized pulse sequences for frequencies below and above 10 MHz, respectively. 37 The representative magnetization recovery plots along with the fits corresponding to cubic and hexagonal phases are displayed in Figure S2.…”

Section: ■ Materials and Methodsmentioning

confidence: 99%

“…Methodical spin-relaxation studies, in particular R 1 , facilitated the individual block dynamics of PPO as well as PEO of copolymers F68 (EO 8 0 PO 2 7 EO 8 0 ), F108 (EO 1 4 1 PO 4 4 EO 1 4 1 ), and F127 (EO 101 PO 56 EO 101 ), revealed by the multiexponential nature of R 1 , which is sensitive to PPO/PEO composition. 35 The obtained FFC NMR profiles for isotropic and cubic phases reflect weak frequency dispersions of R 1 in the low-frequency regime (5−100 kHz), while relatively ordered phases such as hexagonal and lamellar phases encountered steeper dispersions in the same frequency range, as evident from Figure 2. Similar observations have been noted previously in the isotropic and mesophases of polymeric nematogen polydiethylsiloxane (PDES) 17 and thermotropic mesogens.…”

Section: ■ Materials and Methodsmentioning

confidence: 99%

See 2 more Smart Citations

Molecular Dynamics in the Lyophases of Copolymer P123 Investigated with FFC NMR Relaxometry

2018

Self Cite

View full text Add to dashboard Cite

Associative block copolymers of the type (EO) x (PO) y (EO) x (where EO and PO represent ethylene and propylene oxides, respectively) in aqueous solution have far reaching commercial applications such as solubilization, controlled-drug delivery, etc. The molecular dynamics of a self-associating triblock copolymer (EO) 20 (PO) 70 (EO) 20 (known as P123 with a molecular weight of ∼5800), in aqueous solution (D 2 O), consisting of various lyotropic liquid crystalline phases such as isotropic micellar, cubic, hexagonal, and lamellar phases, is investigated using the fast field cycling nuclear magnetic resonance (FFC NMR) relaxometry technique in the Larmor frequency range from 5 kHz to 30 MHz. A nuclear spin-relaxation model consisting of chain modes (Rouse modes) and order fluctuation (OF) modes typical for polymers and liquid crystals, respectively, is considered to explain the observed proton magnetic relaxation dispersion (PMRD) data in the lyophases under investigation. The PMRD analysis in both isotropic micellar and cubic phases revealed a Rouse frequency dependence of spin−lattice relaxation rate (R 1 ), i.e., R 1 ∝ −τ s ln(ωτ s ), in the entire frequency range of study. Hexagonal and lamellar phase data show Rouse modes as well as OF modes, leaving the signature of the latter as R 1 ∝ ω −p , where p ∼ 0.5 is typical for nematic mesogens. The activation energies were also determined from segmental correlation times in the lyophases of study. To the best of our knowledge, the present FFC NMR relaxometry study is unique and quantitative in unraveling molecular dynamics of the associative copolymer P123 in aqueous solution.

show abstract

Dynamics of Proton Transport in Polyethylene Oxide (PEO) with Ammonium Perchlorate (NH₄ClO₄)

Pratap

Singh

et al. 2023

Macromolecular Symposia

View full text Add to dashboard Cite

NH4ClO4 has a very high ionic conductivity ∼ 10−5 Scm −1 in which probable charge carrying mobile species is H+ ion apart from the anion ClO4−. The H+ can be derived either from the -CH2-CH2-of the polymer PEO chain or from the NH4+ of the complexing salt. In order to identify the mobile H+ species and to investigate its dynamics, a wide-line nuclear magnetic resonance (NMR) study has been carried as a function of temperature. The two types of H+ species, as stated above, have been found to show different temperature dependence of the respective NMR-linewidths. It has been established that only one of these H+ species (i.e., belonging to NH4+ cation) contributes predominantly to the room temperature conductivity.

show abstract

Rouse dynamics in PEO-PPO-PEO block-copolymers in aqueous solution as observed through fast field-cycling NMR relaxometry

Cited by 10 publications

References 58 publications

Probing the Interactions of Porphyrins with Macromolecules Using NMR Spectroscopy Techniques

Probing the Interactions of Porphyrins with Macromolecules Using NMR Spectroscopy Techniques

Molecular Dynamics in the Lyophases of Copolymer P123 Investigated with FFC NMR Relaxometry

Dynamics of Proton Transport in Polyethylene Oxide (PEO) with Ammonium Perchlorate (NH₄ClO₄)

Contact Info

Product

Resources

About

Rouse dynamics in PEO-PPO-PEO block-copolymers in aqueous solution as observed through fast field-cycling NMR relaxometry

Cited by 10 publications

References 58 publications

Probing the Interactions of Porphyrins with Macromolecules Using NMR Spectroscopy Techniques

Probing the Interactions of Porphyrins with Macromolecules Using NMR Spectroscopy Techniques

Molecular Dynamics in the Lyophases of Copolymer P123 Investigated with FFC NMR Relaxometry

Dynamics of Proton Transport in Polyethylene Oxide (PEO) with Ammonium Perchlorate (NH4ClO4)

Contact Info

Product

Resources

About

Dynamics of Proton Transport in Polyethylene Oxide (PEO) with Ammonium Perchlorate (NH₄ClO₄)