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Title: Microviscosity in Pluronic and Tetronic poly(ethylene oxide)-poly(propylene oxide) block copolymer micelles

Abstract

The micellar microviscosity afforded by Pluronic and Tetronic poly(ethylene oxide)-poly(propylene oxide) block copolymer aqueous solutions has been investigated by fluorescence and NMR spectroscopy. Comparison is made with bulk poly(propylene oxide) (PPO) samples of different molecular weights. The microviscosity in Pluronic PEO-PPO-PEO copolymer micelles is much larger than that observed in conventional surfactant micelles and depends strongly on the size of the hydrophobic PPO block: the larger this block, the higher the viscosity. Above the critical micellar temperature (CMT), as temperature increases, the microviscosity decreases. However, this decrease is not as important as that observed in bulk PPO. Hence, the relative microviscosity, defined as the ratio of the two observed phenomena, increases. This suggests structural transformation of the micelles resulting in a core becoming more and more compact as temperature increases. Such results have been confirmed by NMR studies that showed broadening of the PPO peak and relatively constant spin-lattice relaxation time, T[sub i], with increasing temperature while the PEO signal remained relatively sharp with an exponential increase in T[sub 1]. 30 refs., 9 figs., 1 tab.

Authors:
; ; ;  [1]
  1. Massachusetts Inst. of Technology, Cambridge, MA (United States)
Publication Date:
OSTI Identifier:
6539154
DOE Contract Number:  
FG02-92ER14262
Resource Type:
Journal Article
Journal Name:
Langmuir; (United States)
Additional Journal Information:
Journal Volume: 11:1; Journal ID: ISSN 0743-7463
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; 36 MATERIALS SCIENCE; 74 ATOMIC AND MOLECULAR PHYSICS; COPOLYMERS; FLUORESCENCE SPECTROSCOPY; NMR SPECTRA; SPIN-LATTICE RELAXATION; VISCOSITY; MICELLAR SYSTEMS; POLYETHYLENE GLYCOLS; TEMPERATURE DEPENDENCE; ALCOHOLS; EMISSION SPECTROSCOPY; GLYCOLS; HYDROXY COMPOUNDS; ORGANIC COMPOUNDS; ORGANIC POLYMERS; POLYMERS; RELAXATION; SPECTRA; SPECTROSCOPY; 400201* - Chemical & Physicochemical Properties; 360600 - Other Materials; 360602 - Other Materials- Structure & Phase Studies; 664200 - Spectra of Atoms & Molecules & their Interactions with Photons- (1992-)

Citation Formats

Nivaggioli, T, Tsao, B, Alexandridis, P, and Hatton, T A. Microviscosity in Pluronic and Tetronic poly(ethylene oxide)-poly(propylene oxide) block copolymer micelles. United States: N. p., 1995. Web. doi:10.1021/la00001a023.
Nivaggioli, T, Tsao, B, Alexandridis, P, & Hatton, T A. Microviscosity in Pluronic and Tetronic poly(ethylene oxide)-poly(propylene oxide) block copolymer micelles. United States. doi:10.1021/la00001a023.
Nivaggioli, T, Tsao, B, Alexandridis, P, and Hatton, T A. Sun . "Microviscosity in Pluronic and Tetronic poly(ethylene oxide)-poly(propylene oxide) block copolymer micelles". United States. doi:10.1021/la00001a023.
@article{osti_6539154,
title = {Microviscosity in Pluronic and Tetronic poly(ethylene oxide)-poly(propylene oxide) block copolymer micelles},
author = {Nivaggioli, T and Tsao, B and Alexandridis, P and Hatton, T A},
abstractNote = {The micellar microviscosity afforded by Pluronic and Tetronic poly(ethylene oxide)-poly(propylene oxide) block copolymer aqueous solutions has been investigated by fluorescence and NMR spectroscopy. Comparison is made with bulk poly(propylene oxide) (PPO) samples of different molecular weights. The microviscosity in Pluronic PEO-PPO-PEO copolymer micelles is much larger than that observed in conventional surfactant micelles and depends strongly on the size of the hydrophobic PPO block: the larger this block, the higher the viscosity. Above the critical micellar temperature (CMT), as temperature increases, the microviscosity decreases. However, this decrease is not as important as that observed in bulk PPO. Hence, the relative microviscosity, defined as the ratio of the two observed phenomena, increases. This suggests structural transformation of the micelles resulting in a core becoming more and more compact as temperature increases. Such results have been confirmed by NMR studies that showed broadening of the PPO peak and relatively constant spin-lattice relaxation time, T[sub i], with increasing temperature while the PEO signal remained relatively sharp with an exponential increase in T[sub 1]. 30 refs., 9 figs., 1 tab.},
doi = {10.1021/la00001a023},
journal = {Langmuir; (United States)},
issn = {0743-7463},
number = ,
volume = 11:1,
place = {United States},
year = {1995},
month = {1}
}