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Calculation of Conformational Properties and Rouse Relaxation Times of PAMAM‐EDA Dendrimers under Different pH Conditions
Author(s) -
Freire Juan J.,
Rubio Ana M.,
McBride Carl
Publication year - 2016
Publication title -
macromolecular theory and simulations
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.37
H-Index - 56
eISSN - 1521-3919
pISSN - 1022-1344
DOI - 10.1002/mats.201600012
Subject(s) - protonation , dendrimer , relaxation (psychology) , chemistry , diffusion , monte carlo method , chemical physics , computational chemistry , thermodynamics , polymer chemistry , physics , organic chemistry , mathematics , ion , social psychology , psychology , statistics
A Monte Carlo study has been performed for protonated and non‐protonated coarse‐grained PAMAM‐EDA of generations ( G ) ranging from 2 to 6. This study calculates sizes, asphericities, and global and external dendrimer density profiles that confirm features previously found in other studies. It is shown that form factors do not change significantly with protonation. Diffusion coefficients, intrinsic viscosities, and Rouse relaxation times are computed as conformational averages. The hydrodynamic properties and their change with protonation are in good agreement with available experimental data. Some differences between the neutral and protonated molecules are noticeable in the case of the relaxation times corresponding to the higher generation numbers ( G > 4). These features indicate that pH may play a role in the internal dynamics of dendrimers. The complex modulus curves have also been computed. When in reduced units to discount size effects, the protonation effect is seen to be very small.