Spatial Distribution of Intra-Molecular Water and Polymeric Components in Polyelectrolyte Dendrimers Revealed by Small Angle Scattering Investigations

Published

October 14, 2011

Author(s)

Bin Wu, Xin Li, Changwoo Do, Tae-Hwan Kim, Chwen-Yang Shew, Yun Liu, Jun Yang, Kunlun Hong, Lionel Porcar, Chun-Yu Chen, Emily L. Liu, Gregory S. Smith, Kenneth W. Herwig, Wei-Ren Chen

Abstract

An experimental scheme using contrast variation small angle neutron scattering technique (SANS), is developed to investigate the structural characteristics of amine-terminated poly(amidoamine) dendrimers (PAMAM) solutions. Using this methodology, we present the dependence of both the intradendrimer water and the polymer distribution on molecular protonation, which can be precisely adjusted by tuning the pH of the solution. Assuming spherical symmetry of the spatial arrangement of the constituent components of dendrimer, and the atomic ratio of hydrogen-to-deuterium for the solvent residing within the cavities of dendrimer is identical to that for the solvent outside dendrimer, the intradendrimer water distribution along the radial direction is determined. Our result clearly reveals an outward relocation of the peripheral groups, as well as the enhanced intra-dendrimer hydration, upon increasing the molecular protonation and therefore allows the determination of segmental backfolding in a quantitative manner. The connection between these charge-induced structural changes and our recently observed progressively active segmental dynamics is also discussed.

Citation

Journal of Chemical Physics

Volume

135

Issue

14

Pub Type

Journals

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Keywords

SANS, dendrimer, water distribution

Citation

Wu, B. , Li, X. , Do, C. , Kim, T. , Shew, C. , Liu, Y. , Yang, J. , Hong, K. , Porcar, L. , Chen, C. , Liu, E. , Smith, G. , Herwig, K. and Chen, W. (2011), Spatial Distribution of Intra-Molecular Water and Polymeric Components in Polyelectrolyte Dendrimers Revealed by Small Angle Scattering Investigations, Journal of Chemical Physics, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=909408 (Accessed July 18, 2024)