Synthesis and Electrorheological Response of Graphene Oxide/Polydiphenylamine Microsheet Composite Particles

Abstract

Conducting graphene oxide/polydiphenylamine (GO/PDPA) microsheet nanocomposite particles were fabricated via in-situ oxidative polymerization using diphenylamine in the presence of GO. The morphological structures and dimensions of the fabricated GO/PDPA composites were evaluated using transmission electron microscopy and scanning electron microscopy. Electrorheological (ER) responses and creep behaviors of an ER fluid consisting of the GO/PDPA composites when suspended in silicone oil were evaluated using a rotational rheometer under input electric field. Three different types of yield stresses were examined along with dielectric analysis, demonstrating their actively tunable ER behaviors.

Transformation of Cellulose via Two-Step Carbonization to Conducting Carbonaceous Particles and Their Outstanding Electrorheological Performance

“…The value of yield stress, τ y , expressing the stress which the liquid had to overcome to begin to flow, was more than 100 Pa for the ER fluid based on HTC-TC600-Cellulose at the electric field strength of 1.5 kV mm −1 (Figure 6c). The found ER performance is outstanding in comparison to the other published cellulose-based works of research [26]-where such results have not been achieved at such concentrations-and even exceeds most of the so-far-presented results for ER fluids based on other carbonized systems [32,34,42] or stateof-the-art materials [12,43,44]. The increased conductivity of HTC-TC600-Cellulose further influences the leaking current through its ER fluid, determining interactions between the particles.…”

“…One of the proposed applications for cellulose particles is their utilization as a dispersed phase in electrorheological (ER) fluids [8][9][10], which are systems whose rheological behavior can be controlled via applied external electric fields [11]. While, in the absence of an electric field, electrically polarizable particles are randomly dispersed in continuous non-conducting medium and the fluid exhibits Newtonian behavior, in its presence, particles align to its direction creating rigid chain-like structures [12]. The fluid then behaves as viscoplastic material with a certain yield stress.…”

Electrorheological Fluids of GO/Graphene-Based Nanoplates

“…In addition to poly (methacrylate) polymers, Gao et al [ 82 ] used polydiphenylamine (PDPA) to modify GO. As shown in Figure 5 a, diphenylamine (DPA) monomer was first adsorbed onto the surface of GO, then APS initiator was added to initiate in situ polymerization to prepare GO/PDPA composite ( Figure 5 b).…”

“… Schematic preparation of GO/PDPA by in situ oxide polymerization of DPA on the surface of GO ( a ) and corresponding TEM images of GO/PDPA ( b ) with different resolutions [ 82 ]. …”

Magnetite/Poly(ortho-anisidine) Composite Particles and Their Electrorheological Response

“…Thus, the particles are aligned in the direction of the E owing to electric dipole–dipole interactions between the particles, forming a chain structure and changing its phase to a solid-like state within milliseconds [ 9 , 10 , 11 ]. This behavior is reversible when the E is removed again, wherein it returns to the liquid state and exhibits Newtonian fluid-like behavior [ 12 , 13 , 14 , 15 , 16 , 17 ]. Due to their artificial controllability and drastic responses and excellent mechanical properties with high yield stresses, ER suspensions have been adopted in various industrial fields such as clutches, brakes, dampers, and shock absorbers [ 18 , 19 ].…”