Extension-induced dispersion of multi-walled carbon nanotube in non-Newtonian fluid
SEM pictures of carbon nanotube clumps ((a) 250x, (b) 60,000x). (c) is the sedimentation test of carbon nanotube in vials with four different solutions: from left, 5 wt% sodiumdodecyl sulfate, 5 wt% dodecyltrimethyl-ammoniumbromide, 2-chloropropane, and PIB/PB.
Diagram of extension-induced mixer: (a) top view, (b) front view of extension-induced mixer. Two axes are rotating in opposite senses to extend and fold a viscoelastic liquid band continuously.
Sequence of the extension-induced mixing mechanism for one cycle.
Tracing of rotating bars.
Torque measurement (a) of rotating bar with time and (b) its variation after being loaded with mBF in extension-induced mixer. In (a), even without a loaded sample torque shows a periodic variation due to the weight of the arm and bar. With a loaded sample, the torque shows a double periodic variation. The larger peak corresponds to the extension of a folded band while the smaller peak corresponds to the extension of a single band.
Optical microscopic pictures of (a) hand-mixed mBF05, (b) mechanically mixed mBF05, and mBF05 (c) under shear flow and (d) under extensional flow. Scale bar is .
Comparison of viscosity of mBF, extended mBF for , hand mixed of CNT with mBF or extended mBF.
Comparison of storage moduli of mBF, extended mBF for , hand-mixed mBF with CNT and extended mBF. Due to degradation, terminal values are lowered for extended samples.
Viscosity of mBF suspensions with CNTs. As mixing time increases, viscosity increases. The increase is more conspicuous with more CNTs.
OM pictures of (a) hand-mixed mBF03, (b) mBF03 under extensional flow for ten days, and (c) its Cryo-TEM picture. Scale bar is .
Comparison of viscosity of mBF05, mBF15 extended at different rates for . Higher extensional rate gives larger change in viscosity.
The maximum torque of mBF, mBF05, mBF15 under extensional flow at the extensional rate of for . Due to degradation, the torque decreases continuously with time. Strain is obtained by multiplying mixing time. Here we added 100 to strain value to avoid the problem at zero strain in logarithmic plot.
Comparison of torque for a rotation of mBF05, mBF15 (a) after and (b) under extensional flow at the extensional rate of .
Composition of suspensions.
Maximum torque and its ratio with extension peak of mBF05 and mBF15.
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