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![SEM images of synthesized polyaniline (PANI): (a) spheres, reprinted with permission from [55]; Copyright Spring Nature, 2013; (b) fibers, reprinted with permission from [52]. Copyright American Chemical Society, 2009; (c) urchin-like, reprinted with permission from [56]. Copyright John Wiley and Sons, 2009; and (d) nanotubes, reprinted with permission from [57]. Copyright American Chemical Society, 2006.](publication/328740705/figure/fig2/AS:689594894921736@1541423643535/SEM-images-of-synthesized-polyaniline-PANI-a-spheres-reprinted-with-permission-from.png)
SEM images of synthesized polyaniline (PANI): (a) spheres, reprinted with permission from [55]; Copyright Spring Nature, 2013; (b) fibers, reprinted with permission from [52]. Copyright American Chemical Society, 2009; (c) urchin-like, reprinted with permission from [56]. Copyright John Wiley and Sons, 2009; and (d) nanotubes, reprinted with permission from [57]. Copyright American Chemical Society, 2006.
Source publication
![Table 1 . Dielectric properties of PIL suspensions [103].](publication/328740705/figure/tbl1/AS:689594899111936@1541423644076/Dielectric-properties-of-PIL-suspensions-103_Q320.jpg)
Electro-responsive smart electrorheological (ER) fluids consist of electrically polarizing organic or inorganic particles and insulating oils in general. In this study, we focus on various conducting polymers of polyaniline and its derivatives and copolymers, along with polypyrrole and poly(ionic liquid), which are adopted as smart and functional m...
Contexts in source publication
Context 1
... morphologies of a synthesized PANI are irregular. However, using some methods, such as interfacial polymerization [51] and rapid mixing method [52], and using a surfactant or template [53] to direct PANI growth, we can obtain various shapes of fibers, tubes, spheres, and even urchin-like particles (shown in Figure 3). ...
Context 2
... morphologies of a synthesized PANI are irregular. However, using some methods, such as interfacial polymerization [51] and rapid mixing method [52], and using a surfactant or template [53] to direct PANI growth, we can obtain various shapes of fibers, tubes, spheres, and even urchin-like particles (shown in Figure 3). ...
Citations
... These lubricants require the application of an electric field, which alters the behavior of bearing that makes it possible to control the performance. ERFs technology has been used in various engineering applications and tribo components/devices such as shock absorbers, brakes, haptic devices, virtual reality, hydraulics, prosthetics, robotics, automotive applications, clutches, dampers, etc. Sheng and Wen (19), Stanway,et al. (20), Lu, et al. (21). ...
... Seo-Seo model allows to calculate the static yield stress (τ sy ) values by taking the structural realignments at low shear rates and Papanastasiou model into account which describes the entire flow curve of non-Newtonian fluids after yielding. Additionally, Seo-Seo model provides better predictions for ER fluids at high and low shear rate regions than commonly used Cho-Choi-John (CCJ) model [76]. If the yield stresses of ER fluids are proportional to E 2 at low electric field strengths and E 3/2 at high field strengths, the Seo-Seo model is expected to be applicable [77]. ...
Coal is used in most of the power and chemical plants to meet energy needs which produce various waste ashes. Reuse of these ashes as electroactive materials has great importance for sustainable development. In this study, it was detected that the main components of coal fly (CFA) and bottom ashes (CBA) were oxides of silica (SiO<sub>2</sub>), iron (Fe<sub>2</sub>O<sub>3</sub>), aluminium (Al<sub>2</sub>O<sub>3</sub>), and magnesium (MgO), besides carbon. These are well-known electrorheological (ER) active materials. The aim of this study is to reveal dielectric and electroactive vibration damping capabilities of CFA and CBA. According to the dielectric and ER flow tests carried out in insulating silicone oil (SO), the optimum concentration of particles was determined to be 35 wt.% for both ashes. Higher ER yield stress (τ<sub>y</sub> = 135 Pa), higher ER efficiency (32.8), and better viscoelastic properties (τ<sub>c</sub> = 128 Pa, G' = 680 kPa) under 3.0 kV mm<sup>-1</sup> applied electric field were obtained for 35CFA/SO suspension system compared to 35CBA/SO (τ<sub>y</sub> = 125 Pa, ER<sub>eff</sub> = 24.0, τ<sub>c</sub> = 55 Pa, G' = 260 kPa). Although it was concluded that both ashes can be upcycled to sustainable and smart vibration damping alternative materials, better performance was observed for CFA particles.
... where, 0 is the dynamic yield stress defined as the stress extrapolated from the low shear rate region, α is related to the decrease in the stress, β is the parameter for the high shear rate region, t 1 and t 2 are time constants, and η ∞ is the viscosity at a high shear rate and is interpreted as the zero-field viscosity. This model was observed to provide a good indication of the ER characteristics over the whole shear rate range, including the reduced shear stress phenomenon [39,40]. ...
Electrorheological (ER) technology is an advanced technology based on ER effects. The most common material in ER technology is an electrorheological fluid (ERF), which is a type of smart soft material. The viscosity of ERF is reversibly adjustable by an applied electric field. A new type of electroresponsive soft material, electrorheological elastomer (ERE), which is a derivative of ERFs, has attracted wide attention due to its advantages of not precipitating and easy packaging. ER materials are widely applied in mechanical engineering due to their reversibly tunable characteristics, fast response, and low energy consumption. In addition to basic ER material fabrication and application, ER technology is also used in energy material preparation, oil transportation, and energy storage. The application of ER technology in the energy field provides a good example of the potential applications of ER technology in other fields. This article systematically summarizes the research status and future development prospects of ER technology in materials, energy, and mechanical engineering from the mechanism to application, combined with the latest research results.
... 1,2 One of their potential applications with strong current research interest is the development of electrorheological (ER) materials based on conducting polymers in the form of nanoparticles suspended in slightly viscous media such as silicone oil. 3,4 Their highly anisotropic electrical polarizability is particularly conducive to good ER properties. ...
Nanoparticles and sub-microparticles of the conducting polymers polyaniline (PANI), polyanisidine (PoANIS) and their copolymers were synthesised, deprotonated and dispersed in viscous media in order to study the influence of their synthetic conditions and of steric stabilisers (cellulose-based materials) on the physical, chemical and morphological characteristics of the polymers. Electrorheological (ER) measurements were performed and related to the polymer properties. The polymer particles had various loadings of stabilisers, depending on the polymer/stabiliser interactions and the stabiliser concentration. When stabilised with hydroxyethylcellulose (HEC), the PANI particles contained traces of HEC, while PoANIS, less stabilised by the electron-rich HEC molecules, did not. Stabilised PANI-HEC synthesised at 0°C readily formed small fibres that, when deprotonated, displayed a large electrorheological response (yield stress ca. 800 Pa at 3.2 kV.mm ⁻¹ ). PoANIS prepared under the same conditions yielded a polydisperse cenospheric material with no ER activity.
... Charge carriers in conducting polymers contribute to the observed increased polarizability [57]. NPs, which were originally insulating materials, became conductive after capping with PT, PPy, and PANI owing to the generation of delocalized charge carriers in the -conjugated backbones. ...
Hollow TiO2 nanoparticles (HNPs) capped with conducting polymers, such as polythio-phene (PT), polypyrrole (PPy), and polyaniline (PANI), have been studied to be used as polariza-bility-tunable electrorheological (ER) fluids. The hollow shape of TiO2 nanoparticles, achieved by the removal of the SiO2 template, offers colloidal dispersion stability in silicone oil owing to the high number density. Conducting polymer shells, introduced on the nanoparticle surface using vapor deposition polymerization method, improve the yield stress of the corresponding ER fluids in the order of PANI < PPy < PT. PT-HNPs exhibited the highest yield stress of ca. 94.2 Pa, which is 5.0-, 1.5-, and 9.6-times higher than that of PANI-, PPy-, and bare HNPs, respectively. The improved ER response upon tuning with polymer shells is attributed to the space charge contribution arising from the movement of the charge carriers trapped by the heterogeneous interface. The ER response of studied ER fluids is consistent with the corresponding polarizability results as indicated by the permittivity and electrophoretic mobility measurements. In conclusion, the synergistic effect of hollow nanostructures and conducting polymer capping effectively enhanced the ER performance.
... Typically, ERFs are suspensions consisting of liquid dielectric media, often silicone oil, and easily polarizable filler particles. 29 The main mechanism of the effect is associated with differences in the dielectric permittivity and conductivity of the filler and the medium leading to polarization of particles in electric field and columnar structures formation. 30 ERFs have great potential in various fields of technology such as dampers, clutches, robotics, sensors, microfluidics etc. 31 That is why the search for new fillers revealing electrorheological activity is an urgent task. ...
Effect of in situ formed silver nanoparticles doping on electrorheological response of highly porous chitosan particles in suspensions of polydimethylsiloxane (silicone oil) is considered. Silver nanoparticles are directly reduced by chitosan from solution. Highly porous chitosan particles with different silver content are fabricated by spraying from solution followed by freeze-drying. A high and stable electrorheological response of suspensions in wide range of electric field strength is observed at a very low filler content of 1 wt%. The nature of the electrorheological effect is considered from the standpoint of dielectric spectroscopy. The activation energies of polarization processes are determined from the temperature dependences of the dielectric loss modulus. The study shows the opportunity to control the properties of stimuli-responsive materials by changing the structure and physicochemical properties of the functional filler. This approach opens up new possibilities for creating materials with high performance and predetermined properties.
... Anhydrous semiconducting polymers are widely used to create high performance ERFs [264,265]. The common properties of these polymers are electronic conductivity due to the presence of a conjugated p-system, thermal stability, as well as facile synthesis. ...
The presented review is an attempt to systematize the enormous scientific knowledge accumulated over several decades in the field of electrorheology. The review examines the basic principles of the elec-trorheological effect and its physical foundations, approaches of rheological description, and widely uses experimental techniques and methods. A roadmap for modern electrorheological fluids has been proposed. Various compositions of electrorheological fluids and the types of used fillers are considered in detail. The exceptional wideness of the operational characteristics of materials with electrorheological activity is shown, as well as their areas of application. The general modern research trends and directions that are still being developed are also noted. Particular attention of researchers is directed to materials with a low concentration of the dispersed phase and a contrasting transition from viscous to elastic behavior under an electric field. In this regard, fillers with high aspect ratio are widely considered for electrorheological fluids. It is assumed that this review will be useful not only for a novice reader who has just become familiar with the concept of electrorheological fluids, but also for an experienced researcher, in order to better understand the nature of the effect. The review can promote to reach the goal of creating materials with tunable and predetermined properties.
... Both G 0 and G 00 increased with the rGO introducing in the lower frequent zone (Fig. 6b and c). However, G 0 reached a platform in lower frequent zone for PVA/P-rGO composite and PVA/I-P-rGO composite hydrogels, which may be caused by the interfacial interactions between PVA chains and the fillers [24]. ...
The most previous research aimed to electromagnetic interference shielding effectiveness (EMI SE) was focused on X-band, which were normally used in communications for satellites. Nowadays, the growth of terahertz technology for 6G communication transfigures mobile and information acquisition. However, few researches have broadcasted the fabrication of hydrogels with application in dual-band EMI SE in X-band and terahertz band (THz-band). Herein, polyvinyl alcohol (PVA) hydrogels applied to dual-band electromagnetic interference (EMI) shielding were prepared by a facile approach. Firstly, reduced graphene oxide (rGO) were modified by polypyrrole (PPy) and ionic liquids (IL) on its nano-sheets to increase the conductivity. Then, the modified rGO (I-P-rGO) was incorporated into PVA solution to in situ form the heterogeneous conducting network in the deformable PVA hydrogels. The obtained PVA/I-P-rGO composite hydrogels exhibited high EMI SE of 32.9 dB in X-band and 22.4 dB in THz-band with 10.0 wt% fillers content due to the heterogeneous conducting network architecture, which opens an avenue for hydrogels applied in shielding electromagnetic waves in X-band and THz-band band at the same time.
Graphical abstract
... Electroactive polymers are classified into several groups such as ferroelectric polymers [1][2][3][4][5][6][7], electro-strictive graft polymers [8,9], electro-rheological fluids [10][11][12][13][14], ionic polymer-metal composites [15][16][17][18][19][20], stimuli-responsive gels [21][22][23][24][25], and dielectric elastomers (DEs) [26,27]. DEs are important for a wide range of scientific and industrial processes, as they can be used as smart structures that exhibit large deformations under electrical loadings. ...
... Finally, when put under an increasing quasi-static electrical load, the DE spherical membrane may undergo the static pull-in instability (when N is large and the behaviour is close to that of a neo-Hookean material) and even the snap-through instability (when N is not large and the strain-stiffening effect is marked). The voltage-stretch relationship for this loading is found by taking the time derivative in Eq. (14) to be identically zero: ...
Limiting chain extensibility is a characteristic that plays a vital role in the stretching of highly elastic materials. The Gent model has been widely used to capture this behaviour, as it performs very well in fitting stress-stretch data in simple tension, and involves two material parameters only. Recently, Anssari-Benam and Bucchi (Int. J. Non. Linear. Mech. 128:103626, 2021) introduced a different form of generalised neo-Hookean model, focusing on the molecular structure of elastomers, and showed that their model encompasses all ranges of deformations, performing better than the Gent model in many respects, also with only two parameters. Here we investigate the nonlinear vibration and stability of a dielectric elastomer balloon modelled by that strain energy function. We derive the deformation field in spherical coordinates and the governing equations by the Euler-Lagrange method, assuming that the balloon retains its spherical symmetry as it inflates. We consider in turn that the balloon is under two types of voltages, a pure DC voltage and an AC voltage superimposed on a DC voltage. We analyse the dynamic response of the balloon and identify the influential parameters in the model. We find that the molecular structure of the material, as tracked by the number of segments in a single chain, can control the instability and the pull-in/snap-through critical voltage, as well as chaos and quasi-periodicity. The main result is that balloons made of materials exhibiting early strain-stiffening effects are more stable and less prone to generate chaotic nonlinear vibrations than when made of softer materials, such as those modelled by the neo-Hookean strain-energy density function.
... By contrast, organic ER materials can overcome the defects of inorganics attributed to their soft structure and low density. Conductive polymers (Plachy et al., 2015;Lu et al., 2018), biopolymers Kovaleva et al., 2022), and polyelectrolytes (Schwarz et al., 2013) are the most concerned candidates as organic ER materials. Although organic ER materials can overcome some shortcomings of inorganic materials, they have no major breakthrough in yield stress, and their thermal stability is not as good as that of inorganic materials. ...
Poly (ionic liquid)/TiO2 composite particles were fabricated using a facile one-pot synthesis method, in which the polymerization of the ionic liquid monomer and hydrolysis of the precursor for TiO2 proceeded in one system. The morphological properties of the composite particles were observed by a scanning electron microscope and transmission electron microscope. The chemical and physical structures of the particles were analyzed by a Fourier infrared spectrometer and an X-ray diffractometer, respectively. It was found that in the composite particles, poly (ionic liquid) (PIL) spheres are embedded in the continuous TiO2 phase, forming larger nonspherical particles of ∼10 microns. The rheological properties of PIL and the PIL/TiO2 composite particles dispersed in silicone oil were measured by a rotational rheometer with a high-power supply. At the same electric field, the PIL/TiO2 particles showed higher shear stress and elastic modulus than pure PIL particles at the same electric field. In addition, compared with pure PIL particles, the PIL/TiO2 particles work at higher temperatures, up to 100°C.
