Abstract
We study the shear effect on the lamellar structure of surfactants in water using dissipative particle dynamics simulations. Starting from a lamellar structure without shear flow, we increase the shear rate and then decrease it stepwisely. A weak shear changes the lamellar plane to be parallel to the shear direction though the lamellar normal has no specific direction on the plane normal to the shear direction. By increasing the shear rate, the lamellar normal eventually flips to the vorticity direction regardless of the initial configuration. Lamellar normal would stay along the vorticity direction on decreasing the shear rate. The hysteresis is also found in shear-stress. By varying the shear rate, the time needed to reach the final unique state is significantly shortened compared with that observed with a constant shear rate. We find a correlation between the excess shear-stress and the tilt angle of surfactant in lamellar.
| Original language | English |
|---|---|
| Pages (from-to) | 20-26 |
| Number of pages | 7 |
| Journal | Chemical Physics |
| Volume | 367 |
| Issue number | 1 |
| DOIs | |
| Publication status | Published - Jan 18 2010 |
| Externally published | Yes |
Keywords
- Dissipative particle dynamics
- Hysteresis
- Lamellar
- Shear
ASJC Scopus subject areas
- Physics and Astronomy(all)
- Physical and Theoretical Chemistry