Scaling trend in diffusion coefficients of low generation G0-G3 PAMAM dendrimers in aqueous solution at high and neutral pH

Verónica A. Jiménez, José A. Gavín, Joel B. Alderete

Research output: Contribution to journalArticlepeer-review

16 Citations (Scopus)

Abstract

Aqueous solution diffusion coefficients for G0-G3 PAMAM dendrimers were determined from DOSY-NMR spectroscopy at high and neutral pH. The study was performed in a dilute regime and diffusion coefficients at infinite dilution (D 0) were estimated from the variation of diffusion coefficients with dendrimer concentration. Hydrodynamic radii (Rh) for each dendrimer were estimated from D 0 using the Stoke-Einstein relationship at both pH. According to D 0 and R h values, the structure of G0-G1 PAMAM dendrimers is almost insensitive to pH variations, whereas G2-G3 PAMAM dendrimers undergo swelling at neutral pH, due to surface amino groups protonation. Experimental diffusion coefficients show a scaling trend with the number of dendrimer atoms (N), with scaling laws of the type D 0 ∞ N a, where a takes values of -0.39 and -0.50 at pH 12 and 7, respectively. For the first time, experimental data accounts for the scaling behavior of aqueous diffusion coefficients for low generation PAMAM dendrimers, as previously reported from molecular dynamics simulations.

Original languageEnglish
Pages (from-to)123-128
Number of pages6
JournalStructural Chemistry
Volume23
Issue number1
DOIs
Publication statusPublished - Feb 2012

Keywords

  • DOSY-NMR
  • Diffusion coefficients
  • PAMAM dendrimers
  • PH effects
  • Swelling

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Physical and Theoretical Chemistry

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