Structure and Dynamics of a Bisurea-Based Supramolecular Polymer in <i>n</i>-Dodecane
Toshiyuki Shikata
Takuya Nishida
Benjamin Isare
Mathieu Linares
Roberto Lazzaroni
Laurent Bouteiller
10.1021/jp800495v.s001
https://acs.figshare.com/articles/journal_contribution/Structure_and_Dynamics_of_a_Bisurea_Based_Supramolecular_Polymer_in_i_n_i_Dodecane/2925589
The structure and dynamics of a supramolecular polymer formed by a bisurea-type compound, 2,4-bis(2-ethylhexylureido)toluene (EHUT), in an apolar solvent, <i>n</i>-dodecane (C<sub>12</sub>), were examined in detail. The EHUT/C<sub>12</sub> organo-gel system forms long, dynamic chain-like supramolecular polymers, which lead to an entangled network showing remarkable viscoelastic behavior with two major relaxation modes. A slow relaxation mode with an approximately constant relaxation time, τ<sub>S</sub>, was observed in a flow region and the other, fast, relaxation mode with a time τ<sub>F1</sub> (<τ<sub>S</sub>) was observed in a high-frequency range. Because no dielectric relaxation behavior was observed over a frequency region including the mechanical τ<sub>S</sub> and τ<sub>F1</sub> relaxation modes, the formed supramolecular polymer does not possess any total dipole moment due to antiparallel intermolecular hydrogen bonding of the two ureido groups of each EHUT unit. A structural model for the supramolecular polymer formed in EHUT/C<sub>12</sub> is proposed based on force-field simulations. This proposed model is consistent with all the experimental data concerning this system: flow birefringence measurements, dielectric spectroscopy, SANS, and FTIR.
2008-07-24 00:00:00
EHUT
τ S
τ F 1 relaxation modes
FTIR
dielectric relaxation behavior
SANS
supramolecular polymer
relaxation mode
flow birefringence measurements