Autor(es): Brehm, Tiago ; Pereira, Gonçalo ; Leal, Catarina R. ; Gonçalves, Clara ; Borges, João P. ; Cidade, Maria Teresa
Data: 2015
Identificador Persistente: http://hdl.handle.net/10400.21/5958
Origem: Repositório Científico do Instituto Politécnico de Lisboa
Assunto(s): Electrorheology; Encapsulated 5CB; Suspensions; Silica; PVA; Electrorheology; Electrorheology; Encapsulated 5CB; Encapsulated 5CB; Suspensions; Suspensions; Silica; Silica; PVA; PVA
The electrorheological (ER) effect is known as the change in the apparent viscosity upon the application of an external electric field perpendicular to the flow direction. In this work we present the electrorheological behaviour of suspensions in silicone oil of two different dispersed phases: foams of liquid crystal 4-n-penthyl-4'-cyanobiphenyl (5CB) encapsulated in polyvinyl alcohol (PVA) and nano/microspheres of 5CB encapsulated in silica. We will present the viscosity curves under the application of an electric field ranging between 0 and 3 kV mm(-1). The ER effect was observed for the suspensions of 5CB/PVA but not in the case of 5CB/silica. For the case of the suspensions of 5CB/PVA, the effect of the viscosity of the continuum phase and the concentration of the dispersed phase was analysed, showing that the enhancement of the viscosity of the suspension increases with the concentration, as expected, however the continuum phase viscosity has no significant effect, at least in the investigated viscosity range.
