Jump to main content
Jump to site search
Publishing
Advanced

Issue 2, 2011
Previous Article Next Article

pH Responsiveness of polyelectrolyte dendrimers: a dynamical perspective

Xin Li,ab  Michaela Zamponi,bc  Kunlun Hong,d  Lionel Porcar,e  Chwen-Yang Shew,f  Timothy Jenkins,g  Emily Liu,a  Gregory S. Smith,b  Kenneth W. Herwig,*b  Yun Liu*gh  and  Wei-Ren Chen*bij 
Author affiliations

* Corresponding authors

a Department of Mechanical, Aerospace & Nuclear Engineering, Rensselaer Polytechnic Institute, Troy, USA

b Neutron Scattering Science Division, Oak Ridge National Laboratory, Oak Ridge, USA
E-mail: chenw@ornl.gov, herwigkw@ornl.gov

c Jülich Centre for Neutron Science, Forschungszentrum Jülich, Jülich, Germany

d The Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, USA

e Institut Laue-Langevin, B.P. 156, Grenoble Cedex 9, France

f Department of Chemistry, City University of New York, College of Staten Island, Staten Island, USA

g The NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, USA
E-mail: yunliu@nist.gov

h Department of Chemical Engineering, University of Delaware, Newark, USA

i Joint Institute for Neutron Sciences, Oak Ridge National Laboratory, Oak Ridge, USA

j Department of Chemical & Biomolecular Engineering, the University of Tennessee, Knoxville, USA

Abstract

A combined quasi-elastic neutron scattering (QENS) and high-resolution solution NMR spectroscopy study was conducted to investigate the internal dynamics of aqueous (D2O) G5 PAMAM dendrimer solutions as a function of molecular protonation at room temperature. Localized motion of the dendrimer segments was clearly exhibited in the QENS data analysis while the global, center-of-mass translational diffusion was measured by NMR. Our results unambiguously demonstrate an increased rapidity in local scale (∼ 3 Å) motion upon increasing the molecular protonation. This is contrary to an intuitive picture that increased charge stiffens the dendrimer segments thereby inhibiting local motion. These charge-induced changes may be a result of interactions with the surrounding counterions and water molecules as the segments explore additional intra-dendrimer volume made available by slight electrostatic swelling and redistribution of mass in the dendrimer interior. This observation is relevant to development of a microscopic picture of dendrimer-based packages as guest-molecule delivery vehicles because reorganization of the confining dendrimer segments must be a precursor to guest-molecule release.

Graphical abstract: pH Responsiveness of polyelectrolyte dendrimers: a dynamical perspective

Back to tab navigation
Download options Please wait...

Publication details

The article was received on 12 Jul 2010, accepted on 28 Oct 2010 and first published on 23 Nov 2010


Article type: Paper
DOI: 10.1039/C0SM00671H
Citation: Soft Matter, 2011,7, 618-622
  •   Request permissions

    pH Responsiveness of polyelectrolyte dendrimers: a dynamical perspective

    X. Li, M. Zamponi, K. Hong, L. Porcar, C. Shew, T. Jenkins, E. Liu, G. S. Smith, K. W. Herwig, Y. Liu and W. Chen, Soft Matter, 2011, 7, 618
    DOI: 10.1039/C0SM00671H

    If you are not the author of this article and you wish to reproduce material from it in a third party non-RSC publication you must formally request permission using RightsLink. Go to our Instructions for using RightsLink page for details.

    Authors contributing to RSC publications (journal articles, books or book chapters) do not need to formally request permission to reproduce material contained in this article provided that the correct acknowledgement is given with the reproduced material.

    Reproduced material should be attributed as follows:

    • For reproduction of material from NJC:
      Reproduced from Ref. XX with permission from the Centre National de la Recherche Scientifique (CNRS) and The Royal Society of Chemistry.
    • For reproduction of material from PCCP:
      Reproduced from Ref. XX with permission from the PCCP Owner Societies.
    • For reproduction of material from PPS:
      Reproduced from Ref. XX with permission from the European Society for Photobiology, the European Photochemistry Association, and The Royal Society of Chemistry.
    • For reproduction of material from all other RSC journals and books:
      Reproduced from Ref. XX with permission from The Royal Society of Chemistry.

    If the material has been adapted instead of reproduced from the original RSC publication "Reproduced from" can be substituted with "Adapted from".

    In all cases the Ref. XX is the XXth reference in the list of references.

    If you are the author of this article you do not need to formally request permission to reproduce figures, diagrams etc. contained in this article in third party publications or in a thesis or dissertation provided that the correct acknowledgement is given with the reproduced material.

    Reproduced material should be attributed as follows:

    • For reproduction of material from NJC:
      [Original citation] - Reproduced by permission of The Royal Society of Chemistry (RSC) on behalf of the Centre National de la Recherche Scientifique (CNRS) and the RSC
    • For reproduction of material from PCCP:
      [Original citation] - Reproduced by permission of the PCCP Owner Societies
    • For reproduction of material from PPS:
      [Original citation] - Reproduced by permission of The Royal Society of Chemistry (RSC) on behalf of the European Society for Photobiology, the European Photochemistry Association, and RSC
    • For reproduction of material from all other RSC journals:
      [Original citation] - Reproduced by permission of The Royal Society of Chemistry

    If you are the author of this article you still need to obtain permission to reproduce the whole article in a third party publication with the exception of reproduction of the whole article in a thesis or dissertation.

    Information about reproducing material from RSC articles with different licences is available on our Permission Requests page.

Search articles by author

Spotlight

Advertisements