Articolo in rivista, 2013, ENG, 10.1103/PhysRevE.87.062304

Enhancement of electrorheological effect by particle-fluid interaction

F Aliotta, P Calandra, M Pochylski, RC Ponterio, G Salvato, C Vasi

CNR, Ist Proc Chim Fis, I-98158 Messina, Italy Adam Mickiewicz Univ, Fac Phys, PL-62614 Poznan, Poland

The influence of interactions between particle surface and host fluids in electrorheological suspensions is explored. It is observed that dispersions of nanosized particles of titania in octanoid acid exhibit an anomalously large electrorheologic effect when compared with a similar dispersion of micrometric particles or with a more conventional colloidal suspension of silica in silicone oil. The effect is interpreted as originated by the formation of a thin layer of octanoid acid molecules with the surface of the titania solid particle. The experimental data are fitted with the outcomes of a modified version of conductive models existing in the literature. It is suggested that anomalous large electrorheological effect is mainly originated by the increasing of the effective radius of the nanometric particles, which results in an increasing of the effective volume fraction of the dispersed phase. It is also shown that the deformation of the soft shell around the solid particles, induced by Coulombic force, plays a not negligible role. Some hints for tailoring electrorheologic fluids suitable for different applications are proposed.

Physical review. E, Statistical, nonlinear, and soft matter physics (Print) 87 (6), pp. 062304–?

Keywords

CARBOXYLIC-ACIDS; ER FLUIDS; SUSPENSIONS; NANOPARTICLES; MECHANISMS; DYNAMICS; TIO2

CNR authors

Aliotta Francesco, Ponterio Rosina Celeste, Calandra Pietro, Salvato Gabriele, Vasi Cirino Salvatore

CNR institutes

IPCF – Istituto per i processi chimico-fisici