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Influence of solvent and salt concentration on the alignment properties of acrylamide copolymer gels for the measurement of RDC
Author(s) -
TrigoMouriño Pablo,
NavarroVázquez Armando,
SánchezPedregal Víctor M.
Publication year - 2012
Publication title -
magnetic resonance in chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.483
H-Index - 72
eISSN - 1097-458X
pISSN - 0749-1581
DOI - 10.1002/mrc.3889
Subject(s) - chemistry , copolymer , solvent , salt (chemistry) , sodium , aqueous solution , acrylamide , residual dipolar coupling , ion , sodium salt , polyacrylamide , chloride , polymer chemistry , dipole , inorganic chemistry , polymer , organic chemistry
The dependence of molecular alignment with solvent nature and salt concentration has been investigated for mechanically stretched polyacrylamide copolymer gels. Residual dipolar couplings (RDCs) were recorded for D 2 O, DMSO‐ d 6 , and DMSO‐ d 6 /D 2 O solutions containing different proportions of the solvents and different sodium chloride concentrations. Alignment tensors were determined by fitting the experimental RDCs to the DFT‐computed structure of N ‐methylcodeinium ion. Analysis of the tensors shows that the degree of alignment decreases with the proportion of DMSO‐ d 6 as well as with the concentration of sodium chloride, most likely due to enhanced ion‐pair aggregation. Furthermore, rotation of the alignment tensor is observed when increasing the salt concentration. Copyright © 2012 John Wiley & Sons, Ltd.