Electrorheological properties of poly(acene quinone) radical suspensions

✍ Scribed by Hyoung J. Choi; Min S. Cho; Myung S. Jhon

• Publisher: John Wiley and Sons
• Year: 1997
• Tongue: English
• Weight: 252 KB
• Volume: 8
• Category: Article
• ISSN: 1042-7147
• DOI: 10.1002/(sici)1099-1581(199711)8:11<697::aid-pat703>3.0.co;2-x

✦ Synopsis

As one of many potential electrorheological (ER) materials, poly(acene quinone) radicals (PAQR) were investigated. PAQRs were synthesized and the characteristics of these polymers were examined by using Fourier transform infrared, thermogravimetric analysis and pycnometer techniques.

ER fluids were prepared by dispersing PAQRs in silicone oil at concentrations of 5, 15 and 25 vol%. A Physica rheometer equipped with a high-voltage generator was used to measure the rheological properties of ER fluids. Controlled shear rate and shear stress modes were used for the shear rate sweep measurement in various test conditions.

Shear stresses, from the shear rate sweep experiment, increase with increasing electric fields, and poly(naphthalene quinone) radical (PNQR) ER system shows the highest yield stress among the PAQRs. In the low shear rate regime, shear stress is reduced with shear rate after the maximum point, until a critical shear rate is reached, and then ER fluid behaves as a Newtonian fluid.