Effect of Temperature on Shear-Induced Anisotropic Structure in Polymer Clay Hydrogels

✍ Scribed by Jun Li; Jun Jiang; Chunhua Li; Min Y. Lin; Steven A. Schwarz; Miriam H. Rafailovich; Jonathan Sokolov

• Publisher: John Wiley and Sons
• Year: 2006
• Tongue: English
• Weight: 197 KB
• Volume: 27
• Category: Article
• ISSN: 1022-1336
• DOI: 10.1002/marc.200600438

✦ Synopsis

Abstract

Summary: Shear‐induced orientation of nanoparticles in poly(ethylene oxide)/Laponite RD hydrogels has been investigated by small angle neutron scattering (SANS). As temperature is reduced, anisotropy develops at lower shear rates. The two‐correlation length Debye–Anderson–Brumberger (DAB) model provides a good fit to the experimental data. The deduced short‐range correlation length (≈5 nm) is observed to increase with shear. The long‐range correlation length (≈50 nm) shows a strong directional dependence, and decreases when shear is applied. The relative contribution of long‐range order to the SANS intensity is observed to increase with shear and decrease with temperature.

SANS anisotropy |(I~y~ − I~x~)/(I~y~ + I~x~)| as a function of shear rate and q at 2 °C.

magnified imageSANS anisotropy |(I~y~ − I~x~)/(I~y~ + I~x~)| as a function of shear rate and q at 2 °C.