TY - CHAP

T1 - NMR relaxation in Dendrimers

AU - Markelov, D.A.

AU - Dolgushev, Maxim

AU - Lahderanta, Erkki

N1 - Markelov D.A., Dolgushev M., Lahderanta E./ NMR relaxation in Dendrimers//Book of abstract, 9th International Symposium Molecular Order and Mobility in Polymer Systems, St. Petersburg, Peterhof, June 19-23, 2017, p. O-87

PY - 2017

Y1 - 2017

N2 - This report focuses on recent advances in the theory of local orientational mobility in dendrimersthat reveals in the NMR relaxation [1]. In particular, we summarize recent results of analytic theory[2-3], computer simulations [4-6], and NMR relaxation experiments [7]. The analytic theoryprovides basic means for the analysis of the simulations and experiments by predicting the existenceof two dominating processes: overall branch relaxation and local vibrations. On the other hand, theresults of simulations and experiments complete the picture by a third process of rotation of thedendrimer as a whole.The NMR relaxation reveals a fundamental importance of the local constraints on segments’orientations. Remarkably, the model, in which such constraints are absent, overestimates localvibrations making the NMR relaxation rate functions for segments that have different topological ocation in the dendrimer to be practically indistinguishable. Inclusion of the bending rigidity fixes this flaw by endorsing the process of overall branch relaxation. This leads to a correct recognition of the slower mobility of the segments that are located closer to the dendrimer’s core. The crucial role of the local constraints for the NMR relaxation functions is supported by a series of experiments and simulations.

AB - This report focuses on recent advances in the theory of local orientational mobility in dendrimersthat reveals in the NMR relaxation [1]. In particular, we summarize recent results of analytic theory[2-3], computer simulations [4-6], and NMR relaxation experiments [7]. The analytic theoryprovides basic means for the analysis of the simulations and experiments by predicting the existenceof two dominating processes: overall branch relaxation and local vibrations. On the other hand, theresults of simulations and experiments complete the picture by a third process of rotation of thedendrimer as a whole.The NMR relaxation reveals a fundamental importance of the local constraints on segments’orientations. Remarkably, the model, in which such constraints are absent, overestimates localvibrations making the NMR relaxation rate functions for segments that have different topological ocation in the dendrimer to be practically indistinguishable. Inclusion of the bending rigidity fixes this flaw by endorsing the process of overall branch relaxation. This leads to a correct recognition of the slower mobility of the segments that are located closer to the dendrimer’s core. The crucial role of the local constraints for the NMR relaxation functions is supported by a series of experiments and simulations.

KW - NMR relaxation

KW - dendrimers

M3 - Conference abstracts

SP - O-87

BT - 9-th International Symposium "Molecular Mobility and Order in Polymer Systems"

CY - SPb.

T2 - 9th International Symposium Molecular Mobility and Order<br/>in Polymer Systems

Y2 - 19 June 2017 through 23 June 2017

ER -