title: Enhanced Electrorheological Performance of Nb-Doped TiO2 Microspheres Based Suspensions and Their Behavior Characteristics in Low-Frequency Dielectric Spectroscopy.
abstract: Titanium dioxide and Nb-doped titanium dioxide microspheres with the same size were fabricated by a simple sol-gel method, and the formation mechanism of Nb-doped titanium dioxide microspheres was proposed. Titanium dioxide and Nb-doped titanium dioxide microspheres were adopted as dispersed materials for electrorheological (ER) fluids to investigate the influence of the charge increase introduced by Nb doping on the ER activity. The results showed that Nb doping could effectively enhance the ER performance. Combining with the analysis of dielectric spectroscopy, it was found that the interface polarization of Nb-doped TiO2 ER fluid was larger than that of TiO2 ER fluid, which might be caused by more surface charges in Nb-TiO2 microspheres due to Nb(5+) doping and resulting in enhancement of electric field force and strengthening of fibrous structure. In addition, by comparing and analyzing the permittivity curves of Nb-TiO2/LDPE solid composite and Nb-TiO2/silicone-oil fluid composite, it could be concluded that the enhancement of permittivity at low frequency resulted from the increase of the order degree of dispersed particles in ER fluid rather than from the quasi-dc (QDC) behavior. Moreover, the absolute value of slope of permittivity curves (K) at 0.01 Hz could be utilized as the standard for judging the ability to maintain the chainlike structure. The relationships between polarizability of dispersed particles, dielectric spectrum, parameter K, and ER properties were discussed in detail.
authors.affiliation: Laboratory of Functional and Biological Nanomaterials, College of Materials Science and Engineering, Qingdao University of Science and Technology , Qingdao, Shandong 266061, China.
authors.forename: Xiaosong
authors.initials: X
authors.lastname: Guo
authors.affiliation: Laboratory of Functional and Biological Nanomaterials, College of Materials Science and Engineering, Qingdao University of Science and Technology , Qingdao, Shandong 266061, China.
authors.forename: Yulu
authors.initials: Y
authors.lastname: Chen
authors.affiliation: Laboratory of Functional and Biological Nanomaterials, College of Materials Science and Engineering, Qingdao University of Science and Technology , Qingdao, Shandong 266061, China.
authors.forename: Ming
authors.initials: M
authors.lastname: Su
authors.affiliation: Laboratory of Functional and Biological Nanomaterials, College of Materials Science and Engineering, Qingdao University of Science and Technology , Qingdao, Shandong 266061, China.
authors.forename: Dong
authors.initials: D
authors.lastname: Li
authors.affiliation: Laboratory of Functional and Biological Nanomaterials, College of Materials Science and Engineering, Qingdao University of Science and Technology , Qingdao, Shandong 266061, China.
authors.forename: Guicun
authors.initials: G
authors.lastname: Li
authors.affiliation: Laboratory of Functional and Biological Nanomaterials, College of Materials Science and Engineering, Qingdao University of Science and Technology , Qingdao, Shandong 266061, China.
authors.forename: Chengdong
authors.initials: C
authors.lastname: Li
authors.affiliation: Laboratory of Functional and Biological Nanomaterials, College of Materials Science and Engineering, Qingdao University of Science and Technology , Qingdao, Shandong 266061, China.
authors.forename: Yu
authors.initials: Y
authors.lastname: Tian
authors.affiliation: Laboratory of Functional and Biological Nanomaterials, College of Materials Science and Engineering, Qingdao University of Science and Technology , Qingdao, Shandong 266061, China.
authors.forename: Chuncheng
authors.initials: C
authors.lastname: Hao
authors.affiliation: Laboratory of Functional and Biological Nanomaterials, College of Materials Science and Engineering, Qingdao University of Science and Technology , Qingdao, Shandong 266061, China.
authors.forename: Qingquan
authors.initials: Q
authors.lastname: Lei
keywords: Nb-doped; TiO2 microspheres; electrorheological response; low-frequency dielectric spectroscopy; secondary polarization