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Complex formed in the system hydrophobically modified polyethylene glycol/methylated alpha-cyclodextrin/water. An NMR diffusometry study

Karlson, L; Malmborg, Carin LU ; Thuresson, Krister LU and Söderman, Olle LU (2003) In Colloids and Surfaces A: Physicochemical and Engineering Aspects 228(1-3). p.171-179
Abstract
In aqueous solutions hydrophobically modified polyethylene glycol (HM-PEG) forms a transient polymer network held together by intermolecular hydrophobic associations. In the present investigation we have used NMR-diffusometry to study how the addition of methylated alpha-cyclodextrin (M-alpha-CD) influences the polymer network. The addit

on of M-alpha-CD resulted in an increased mean self-diffusion of HM-PEG,

DHM-PEG, which is referred to a degradation of the polymer network when

hydrophobic associations are disrupted due to complex formation between

the hydrophobic groups of HM-PEG and M-alpha-CD. Addition of small

amounts of M-alpha-CD results in a dramatic increase in DHM-PEG.... (More)
In aqueous solutions hydrophobically modified polyethylene glycol (HM-PEG) forms a transient polymer network held together by intermolecular hydrophobic associations. In the present investigation we have used NMR-diffusometry to study how the addition of methylated alpha-cyclodextrin (M-alpha-CD) influences the polymer network. The addit

on of M-alpha-CD resulted in an increased mean self-diffusion of HM-PEG,

DHM-PEG, which is referred to a degradation of the polymer network when

hydrophobic associations are disrupted due to complex formation between

the hydrophobic groups of HM-PEG and M-alpha-CD. Addition of small

amounts of M-alpha-CD results in a dramatic increase in DHM-PEG. Upon

further addition of M-a-CD the increase in DHM-PEG is less dramatic and

at excess M-alpha-CD, DHM-PEG levels off and equals the mean

self-diffusion coefficient for unmodified PEG with the same molecular

weight. The suggested interpretation is that the addition of the first

molecules of M-alpha-CD mainly reduces the probability for hydrophobic

associations inter-connecting different clusters of polymer micelles

whereas at higher M-alpha-CD concentrations a disengagement of the

individual clusters into separate HM-PEG molecules becomes

important. (C) 2003 Elsevier B.V. All rights reserved. (Less)
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organization
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Contribution to journal
publication status
published
subject
keywords
Hydrophobically modified polyethylene glycol, Methylated α-cyclodextrin, NMR diffusometry
in
Colloids and Surfaces A: Physicochemical and Engineering Aspects
volume
228
issue
1-3
pages
171 - 179
publisher
Elsevier
external identifiers
  • wos:000187181300017
  • scopus:0242593964
ISSN
0927-7757
DOI
language
English
LU publication?
yes
id
26581057-243f-415b-8e79-3eca701348ab (old id 122039)
date added to LUP
2007-07-11 13:48:32
date last changed
2018-05-29 11:31:32
@article{26581057-243f-415b-8e79-3eca701348ab,
  abstract     = {In aqueous solutions hydrophobically modified polyethylene glycol (HM-PEG) forms a transient polymer network held together by intermolecular hydrophobic associations. In the present investigation we have used NMR-diffusometry to study how the addition of methylated alpha-cyclodextrin (M-alpha-CD) influences the polymer network. The addit<br/><br>
on of M-alpha-CD resulted in an increased mean self-diffusion of HM-PEG,<br/><br>
	DHM-PEG, which is referred to a degradation of the polymer network when<br/><br>
	hydrophobic associations are disrupted due to complex formation between<br/><br>
	the hydrophobic groups of HM-PEG and M-alpha-CD. Addition of small<br/><br>
	amounts of M-alpha-CD results in a dramatic increase in DHM-PEG. Upon<br/><br>
	further addition of M-a-CD the increase in DHM-PEG is less dramatic and<br/><br>
	at excess M-alpha-CD, DHM-PEG levels off and equals the mean<br/><br>
	self-diffusion coefficient for unmodified PEG with the same molecular<br/><br>
	weight. The suggested interpretation is that the addition of the first<br/><br>
	molecules of M-alpha-CD mainly reduces the probability for hydrophobic<br/><br>
	associations inter-connecting different clusters of polymer micelles<br/><br>
	whereas at higher M-alpha-CD concentrations a disengagement of the<br/><br>
	individual clusters into separate HM-PEG molecules becomes<br/><br>
	important. (C) 2003 Elsevier B.V. All rights reserved.},
  author       = {Karlson, L and Malmborg, Carin and Thuresson, Krister and Söderman, Olle},
  issn         = {0927-7757},
  keyword      = {Hydrophobically modified polyethylene glycol,Methylated α-cyclodextrin,NMR diffusometry},
  language     = {eng},
  number       = {1-3},
  pages        = {171--179},
  publisher    = {Elsevier},
  series       = {Colloids and Surfaces A: Physicochemical and Engineering Aspects},
  title        = {Complex formed in the system hydrophobically modified polyethylene glycol/methylated alpha-cyclodextrin/water. An NMR diffusometry study},
  url          = {http://dx.doi.org/},
  volume       = {228},
  year         = {2003},
}