Search

Encapsulated polypyrrole (PPy) with different amount in the channels of mesoporous silica (SBA-15) was synthesized. The XRD and N2 adsorption/desorption isotherms analysis show that PPy with different loadings in the channels does not affect the ordered hexagonal structure of resultant PPy/SBA-15 nanocomposites. Further, the electrorheological (ER) properties of the nanocomposites with different PPy loadings were investigated by steady and oscillatory shear experiments. The results reveal that PPy/SBA-15 fluids exhibit typical ER and viscoelastic behavior under the applied electric field and ER response depends mainly on PPy loadings and there is an optimum PPy loading for strong ER effect. [ABSTRACT FROM AUTHOR]

Abstract: In this study, a new mesoporous material with semiconducting polypyrrole (PPy) encapsulated in the channels of mesoporous silica (MCM-41) was synthesized and used as dispersed phase for electrorheological (ER) fluids. Rheological and dielectric properties of PPy-MCM-41 based suspensions were investigated with the conclusion that PPy-MCM-41 fluid exhibits better ER behavior than that without PPy. The static yield stress of 10wt.% PPy-MCM-41 fluid as a function of applied electric field strength shows two different slopes depending on the electric field strength. Furthermore, the dielectric spectra indicate that encapsulated PPy increases the interfacial polarizability of mesoporous material and induces a higher ER effect. [Copyright &y& Elsevier]