Electrorheological properties and structure of (BaTiO(C2O4)2/NH2CONH2)

The core-shell structural (BaTiO(C2O4)2/NH2CONH2) samples of giant electrorheological (ER) activity have been synthesized by a sol-gel method and studied by TEM, X-ray diffraction and IR spectroscopy. From the analysis of the X-ray diffraction, it is found that the component of samples is (BaTiO(C2O4)2/NH2CONH2) with a different content of urea. The observations of the TEM morphology show that (BaTiO(C2O4)2/NH2CONH2) particles are spheral with a size of around 80 nm and a surface coating with 5-10 nm thickness consisting of urea. The samples show an increasing tend of ER effect as the addition of urea increasing. Moreover, by IR spectroscopy study, it is revealed that some peaks of C=O band and C-O band vibrations of BaTiO(C2O4)2 are split into two peaks after urea added. The extent of the splits increase with the increase of urea content, which is resulted by the interaction between the chemical bonds of urea and oxalate of BaTiO(C2O4)2. It is evident that the giant ER activity of the sample has a close relationship with the interfacial polarization between the core and the shell of (BaTiO(C2O4)2/NH2CONH2). - Graphical abstract: TEM images of (BaTiO(C2O4)2/NH2CONH2) particles show the thickness of shell increasing as the urea addition increasing. The enhancement of giant ER activity relate with the increasing interfacial polarization of the core-shell structural (BaTiO(C2O4)2/NH2CONH2)