Linear and Non-Linear Viscoelastic Properties of Fiber Networks
Freiburg Materials Reserach Center (FMF), Albert-Ludwigs-University
Stefan-Meier-Str. 21, 79104 Freiburg, Germany
The molecular
dispersion of carbon nanotubes (CNTs) in matrices is of crucial importance for
the beneficial combination of CNTs superior properties with that of matrix
fluids. Therefore, we dealt with methods enabling the molecular dispersion of
CNTs in low molecular weight fluids and the characterization of dispersions
properties.
We found that CNTs are very well dispersed in ionic liquids such as 1-butyl 3-methyl imidazolium tetrafuoroborate (BMIBF4) together with cosolvents and surfactants. Already for concentrations higher than 0.01 wt.%, the rheological response of these compounds resembles that of isotropic fiber networks. These networks were characterized morphologically by TEM and rheologically by mechanical spectroscopy in the linear and non-linear deformation ranges.
Using models developed for semi flexible biopolymer networks we can understand the obtained results quantitatively. In contrast to actin-networks, the CNT-networks display rather energetic elasticity than entropic. We discuss the reasons for this peculiarity.