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NMR relaxation and ...
NMR relaxation and self-diffusion in aqueous micellar gels of pluronic F-127
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- Shaikhullina, Milyausha (författare)
- Institute of Physics, Kazan Federal University, 420008 Kazan, Russia
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- Khaliullina, Aliya (författare)
- Institute of Physics, Kazan Federal University, 420008 Kazan, Russia. Medical and Biological Physics, Kazan Medical University, 420012 Kazan, Russia
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- Gimatdinov, Rustam (författare)
- Medical and Biological Physics, Kazan Medical University, 420012 Kazan, Russia
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- Butakov, Anatoly (författare)
- Radiophysics and Electronics, Chelyabinsk State University, Chelyabinsk 454001, Russia
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- Chernov, Vladimir (författare)
- Radiophysics and Electronics, Chelyabinsk State University, Chelyabinsk 454001, Russia
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- Filippov, Andrei, PhD, 1957- (författare)
- Luleå tekniska universitet,Kemiteknik,Medical and Biological Physics, Kazan Medical University, 420012 Kazan, Russia
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Institute of Physics, Kazan Federal University, 420008 Kazan, Russia Institute of Physics, Kazan Federal University, 420008 Kazan, Russia Medical and Biological Physics, Kazan Medical University, 420012 Kazan, Russia (creator_code:org_t)
- Elsevier, 2020
- 2020
- Engelska.
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Ingår i: Journal of Molecular Liquids. - : Elsevier. - 0167-7322 .- 1873-3166. ; 306
- Relaterad länk:
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https://doi.org/10.1...
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https://urn.kb.se/re...
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https://doi.org/10.1...
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Abstract
Ämnesord
Stäng
- We studied the transverse NMR relaxation of protons of different chemical groups and diffusion of molecules in an aqueous pluronic F-127 system. The system was studied at concentrations of 15, 21 and 28 wt% and in the temperature range of 293–333 K. The dynamic peculiarities in different phases were analyzed based on the NMR relaxation and diffusion data. Our study demonstrated a correlation between phase states, T2 relaxation times of “solid-like” and “liquid” protons of selected chemical groups of polypropylene oxide (PPO) and polyethylene oxide (PEO) blocks, and diffusion coefficients. Transverse NMR relaxation established that the presence of a “solid-like” component of CH3 protons of PEO blocks is observed only at temperatures and concentrations corresponding to the rigid-gel phase, due to entanglements between micellar coronas. At all temperatures and concentrations, some CH3 protons of PPO blocks and some CH2 protons of PEO blocks show “liquid-like” transverse NMR relaxation. Under the conditions corresponding to formation of the rigid-gel phase of the pluronic, relaxation of the “liquid-like” protons additionally accelerates due to entanglements of micellar coronas. Transition of the system to the rigid-gel phase is accompanied by decrease of diffusion coefficients by a factor of 10–104 relative to the diffusivity of free-moving pluronic micelles in the sol phase. Diffusion measurements show that there are pre-transition phenomena, which are characteristic for temperatures and concentrations near sol-gel phase boundaries.
Ämnesord
- NATURVETENSKAP -- Kemi -- Fysikalisk kemi (hsv//swe)
- NATURAL SCIENCES -- Chemical Sciences -- Physical Chemistry (hsv//eng)
Nyckelord
- Poloxamer
- Block-copolymer
- NMR relaxation
- Molecular mobility
- Phase diagram
- Chemistry of Interfaces
- Gränsytors kemi
Publikations- och innehållstyp
- ref (ämneskategori)
- art (ämneskategori)
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