Abstract
The use of various shearing apparatuses to study the phase behavior of poly(styrene-b-isoprene) diblock copolymer micelles is described. A DMTA rheometer was modified so that one can apply oscillatory shear and obtain the scattering pattern along the shear gradient direction. A cone and plate shear cell was designed to access scattering along the shear vorticity direction, and both oscillatory and steady shear can be applied. The most popular way to employ steady shear on relatively low viscosity fluids is to use a Couette cell, because a high shear rate can be readily achieved without disturbing the sample by overflow. In this work, oscillatory shear was used to obtain a single crystal-like scattering pattern, and thereby to examine the mechanism of the thermotropic transition between face-centered cubic (fee) and body-centered cubic (bcc) lattices. By applying the steady shear, the response of the fee lattices to various shear rates is discussed.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 227-232 |
| Number of pages | 6 |
| Journal | Korea Australia Rheology Journal |
| Volume | 19 |
| Issue number | 4 |
| State | Published - Dec 1 2007 |
Keywords
- Block copolymer micelles
- Body-centered cubic (bcc)
- Face-centered cubic (fee)
- Oscillatory shear
- Shear cell
- Steady shear