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![Structures of various forms of polyaniline: (a) general form; (b) leucomeraldine; (c) emeraldine; (d) pernigraniline [15].](profile/Erol-Sancaktar/publication/249574871/figure/fig10/AS:668217093664780@1536326778958/Structures-of-various-forms-of-polyaniline-a-general-form-b-leucomeraldine-c.png)
Structures of various forms of polyaniline: (a) general form; (b) leucomeraldine; (c) emeraldine; (d) pernigraniline [15].
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The wide range of electrical, electrochemical, and optical properties associated with Polyaniline (PANI) and its composites has made them attractive for many industrial applications. In this study, Emeraldine Salt (ES), which is a doped conducting form of PANI, was chemically prepared in situ using the oxidizing agent ammonium persulphate in the pr...
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... is a high molecular weight (typically 100 000) polymer. Its structure can be represented by the general formula shown in Fig. 1a, with n representing the degree of polymerization, and .1 ¡ y/ the oxidation state, varying from 0.0 to 1.0. Thus, leucoemeraldine (Fig. 1b) corresponds to .1 ¡ y/ D 0, emeraldine (Fig. 1c) has .1 ¡ y/ D 0:5. With .1 ¡ y/ D 1:0, we have the completely oxidized state of the polymer, denoted as pernigraniline, a non-conductive form, ...
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... is a high molecular weight (typically 100 000) polymer. Its structure can be represented by the general formula shown in Fig. 1a, with n representing the degree of polymerization, and .1 ¡ y/ the oxidation state, varying from 0.0 to 1.0. Thus, leucoemeraldine (Fig. 1b) corresponds to .1 ¡ y/ D 0, emeraldine (Fig. 1c) has .1 ¡ y/ D 0:5. With .1 ¡ y/ D 1:0, we have the completely oxidized state of the polymer, denoted as pernigraniline, a non-conductive form, shown in Fig. 1d. All of these states, except leucoemeraldine, can be protonated. The states with no protonation are denoted as the 'base' form, ...
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... is a high molecular weight (typically 100 000) polymer. Its structure can be represented by the general formula shown in Fig. 1a, with n representing the degree of polymerization, and .1 ¡ y/ the oxidation state, varying from 0.0 to 1.0. Thus, leucoemeraldine (Fig. 1b) corresponds to .1 ¡ y/ D 0, emeraldine (Fig. 1c) has .1 ¡ y/ D 0:5. With .1 ¡ y/ D 1:0, we have the completely oxidized state of the polymer, denoted as pernigraniline, a non-conductive form, shown in Fig. 1d. All of these states, except leucoemeraldine, can be protonated. The states with no protonation are denoted as the 'base' form, e.g. emeraldine base (which would be ...
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... 1a, with n representing the degree of polymerization, and .1 ¡ y/ the oxidation state, varying from 0.0 to 1.0. Thus, leucoemeraldine (Fig. 1b) corresponds to .1 ¡ y/ D 0, emeraldine (Fig. 1c) has .1 ¡ y/ D 0:5. With .1 ¡ y/ D 1:0, we have the completely oxidized state of the polymer, denoted as pernigraniline, a non-conductive form, shown in Fig. 1d. All of these states, except leucoemeraldine, can be protonated. The states with no protonation are denoted as the 'base' form, e.g. emeraldine base (which would be non-conductive). After protonation, the polymer is denoted as 'salt'. For example, protonation of the emeraldine base form (Fig. 1c) with HCl yields emeraldine ...
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... protonation, the polymer is denoted as 'salt'. For example, protonation of the emeraldine base form (Fig. 1c) with HCl yields emeraldine hydrochoride, as illustrated in Fig. 2 [12][13][14]. ...
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... resulted in electrical conduction even when the volume fraction of ES powder was above 50%. The use of nitrocellulose solution, however, was successful in obtaining electrical conduction with the addition of the ES powder. The experimental data for resistivity versus ller concentration for ES lled nitrocellulose solution are presented in Fig. 11. The resistivity level obtained for the composite lm when it is lled 50% by volume with the ES powder is higher than that for the homogeneous ES powder under 1.3 to 15.8 MPa pressure range (Figs 9, 10, respectively) by about a factor of 2. This difference increases to as high as seventeen-fold when the lm is lled at 30%. This is in ...
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... experimental data for resistivity versus ller concentration for ES lled nitrocellulose solution are presented in Fig. 11. The resistivity level obtained for the composite lm when it is lled 50% by volume with the ES powder is higher than that for the homogeneous ES powder under 1.3 to 15.8 MPa pressure range (Figs 9, 10, respectively) by about a factor of 2. This difference increases to as high as seventeen-fold when the lm is lled at 30%. This is in line with our expectation that, among other characteristics, the resistivity levels of electrically conductive adhesives are largely dependent on the average length of conductive paths between the conductive particles dispersed in the non-conducting matrix [16,18]. ...
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... series of scanning electron micrographs taken at 200£ magni cation shown in Fig. 12 depict the features of the pure ES powder (Fig. 12a), and pure (Fig. 12b) as well as lled nitrocellulose solution (Fig. 12 c -e) adhesive samples fractured subsequent to cure. In Fig. 12a, we see the polydisperse spherical morphology of the bulk ES powder with an average particle diameter of 5-10 ¹m. Figure 12b shows the homogeneous ...
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... series of scanning electron micrographs taken at 200£ magni cation shown in Fig. 12 depict the features of the pure ES powder (Fig. 12a), and pure (Fig. 12b) as well as lled nitrocellulose solution (Fig. 12 c -e) adhesive samples fractured subsequent to cure. In Fig. 12a, we see the polydisperse spherical morphology of the bulk ES powder with an average particle diameter of 5-10 ¹m. Figure 12b shows the homogeneous morphology of the pure nitrocellulose solution after ...
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... series of scanning electron micrographs taken at 200£ magni cation shown in Fig. 12 depict the features of the pure ES powder (Fig. 12a), and pure (Fig. 12b) as well as lled nitrocellulose solution (Fig. 12 c -e) adhesive samples fractured subsequent to cure. In Fig. 12a, we see the polydisperse spherical morphology of the bulk ES powder with an average particle diameter of 5-10 ¹m. Figure 12b shows the homogeneous morphology of the pure nitrocellulose solution after solidii cation by ...
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... series of scanning electron micrographs taken at 200£ magni cation shown in Fig. 12 depict the features of the pure ES powder (Fig. 12a), and pure (Fig. 12b) as well as lled nitrocellulose solution (Fig. 12 c -e) adhesive samples fractured subsequent to cure. In Fig. 12a, we see the polydisperse spherical morphology of the bulk ES powder with an average particle diameter of 5-10 ¹m. Figure 12b shows the homogeneous morphology of the pure nitrocellulose solution after solidii cation by evaporation and fracture after immersion in liquid nitrogen. ...
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... series of scanning electron micrographs taken at 200£ magni cation shown in Fig. 12 depict the features of the pure ES powder (Fig. 12a), and pure (Fig. 12b) as well as lled nitrocellulose solution (Fig. 12 c -e) adhesive samples fractured subsequent to cure. In Fig. 12a, we see the polydisperse spherical morphology of the bulk ES powder with an average particle diameter of 5-10 ¹m. Figure 12b shows the homogeneous morphology of the pure nitrocellulose solution after solidii cation by evaporation and fracture after immersion in liquid nitrogen. Figures 12c, d, and e reveal that the degree of dispersion ...
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... Fig. 12a, we see the polydisperse spherical morphology of the bulk ES powder with an average particle diameter of 5-10 ¹m. Figure 12b shows the homogeneous morphology of the pure nitrocellulose solution after solidii cation by evaporation and fracture after immersion in liquid nitrogen. Figures 12c, d, and e reveal that the degree of dispersion of ES powder in adhesives with different ller loadings is quite different. ...
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... Fig. 12a, we see the polydisperse spherical morphology of the bulk ES powder with an average particle diameter of 5-10 ¹m. Figure 12b shows the homogeneous morphology of the pure nitrocellulose solution after solidii cation by evaporation and fracture after immersion in liquid nitrogen. Figures 12c, d, and e reveal that the degree of dispersion of ES powder in adhesives with different ller loadings is quite different. Both nitrocellulose solutions lled 40% and 50% by volume with ES particles show the llers to be well dispersed within the insulating (Figs 12d, e). ...
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... 12c, d, and e reveal that the degree of dispersion of ES powder in adhesives with different ller loadings is quite different. Both nitrocellulose solutions lled 40% and 50% by volume with ES particles show the llers to be well dispersed within the insulating (Figs 12d, e). On the other hand, a non-uniform dispersion of the llers is observed for the case of 30% concentration (Fig. 12c). ...
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... degree of dispersion of ES powder in adhesives with different ller loadings is quite different. Both nitrocellulose solutions lled 40% and 50% by volume with ES particles show the llers to be well dispersed within the insulating (Figs 12d, e). On the other hand, a non-uniform dispersion of the llers is observed for the case of 30% concentration (Fig. 12c). In order to examine the mechanical and conduction behaviors of the composite adhesive, single lap joints were prepared using ES lled nitrocellulose adhesive on aluminum or zinc (plated), as well as on silver substrates. The experimental results revealed that the adhesive / substrate interphase had a strong in uence on the electrical ...
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... joints with Ag substrates exhibited durable, and continuous conduction property over a period of 30 days ( Table 2). The joint resistivity in these samples (Table 2) fell in the range between those for the homogeneous ES powder under 1.3 to 15.8 MPa pressure range (Figs 9, 10, respectively), and the composite lm values with above 40% volume fraction ES ller (Fig. 11). When aluminum substrates were used, except for one case, all joints became completely non-conductive within 6 days even though the initial resistivity values (Table 3) were not much higher than those for the corresponding composite lm values (Fig. 11). ...
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... Ag substrates exhibited durable, and continuous conduction property over a period of 30 days ( Table 2). The joint resistivity in these samples (Table 2) fell in the range between those for the homogeneous ES powder under 1.3 to 15.8 MPa pressure range (Figs 9, 10, respectively), and the composite lm values with above 40% volume fraction ES ller (Fig. 11). When aluminum substrates were used, except for one case, all joints became completely non-conductive within 6 days even though the initial resistivity values (Table 3) were not much higher than those for the corresponding composite lm values (Fig. 11). In the case of Zn plated substrates, all joints became completely non-conductive ...
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... (Figs 9, 10, respectively), and the composite lm values with above 40% volume fraction ES ller (Fig. 11). When aluminum substrates were used, except for one case, all joints became completely non-conductive within 6 days even though the initial resistivity values (Table 3) were not much higher than those for the corresponding composite lm values (Fig. 11). In the case of Zn plated substrates, all joints became completely non-conductive within one day. This loss of conduction may be attributed to a complex redox-reaction occurring at the boundary between the composite adhesive and the metal substrate. This reaction results in the formation of a dense, non-conduction layer of metallic ...
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In this study, nitrocellulose (NC) fiber blanket prepared by electrostatic spinning method has been used as a template, and copper nitrate (Cu(NO3)(2)) as an oxidant to synthesise polyaniline nanotubes doped with heteropolyacid (H4SiW12O40, SiW12) using UV light catalytic method. Infrared spectroscopy (IR), X-ray powder diffraction (XRD), scanning...
Citations
... Puncak oksidasi polimer konduktif PANi akan mencapai titik muatan seimbang dengan doping anion yang memiliki struktur ikatan p-elektron yang terdelokalisasi (Aynaou, et al., 2022). (Sancaktar & Liu, 2003) IV. PENUTUP ...
Lapisan tipis Polianilin (PANi) telah berhasil dideposisi secara elektrokimia pada elektroda ITO. Proses elektrokimia dilakukan menggunakan variasi scan rate sebesar 10 mV/s, 25 mV/s, 50 mV/s, 75 mV/s, dan 125 mV/s. Variasi scan rate berpengaruh pada warna dan ketebalan lapisan PANi pada permukaan ITO. Semakin besar scan rate menyebabkan warna lapisan PANi semakin pudar. Hasil karakterisasi FTIR telah mengindentifikasi keberadaan fasa emeraldine salt (ES) pada lapisan PANi yang terdeposisi. Sedangkan dari karakterisasi CV memperlihatkan bahwa dengan meningkatnya scan rate akan memperlebar kurva CV lapisan PANi. Kata Kunci: Polianilin, elektrodeposisi, scan rate, ITO Abstract Polyaniline (PANi) thin films have been successfully deposited electrochemically on ITO electrode. The electrochemical process was carried out using variations scan rate of 10 mV/s, 25 mV/s, 50 mV/s, 75 mV/s, and 125 mV/s. Scan rate variations affect the color and thickness of the PANi layer on the ITO surface. The greater scan rate causes the color of the PANi layer to fade. FTIR characterization results have identified the presence of phases emeraldine salt (ES) on the deposited PANi layer. Meanwhile, CV characterization shows that increasing scan rate will widen the CV curve of the PANi layer. Keywords: Polyaniline, electrodeposition, scan rate, ITO
... Electrically conductive polymers prepared in this fashion still pose many problems with respect to controllable conductivity, environmental stability and mechanical properties [14]. Using ammonium persulphate oxidizing agent in aqueous HCl solution, Sancaktar and Liu [15] produced emeraldine salt (ES; doped PANI), which they used in homogeneous powder as well as in (ES filler -nitrocellulose) adhesive composite forms to study the relationships among electrical resistivity, morphology, viscoelastic and chemical behaviors. Their results showed percolation threshold at ~30% vol of ES powder. ...
Electrically conductive adhesives (ECA’s) are used widely to replace or reinforce lead soldering or conductive metal components in electronic packaging applications such as die attachment, solderless interconnections, component repair, display interconnections, and heat dissipation. Their conductive behavior as well as the associated behaviors such as heat conduction and mechanical behavior (strength, rigidity, deformation and viscoelastic behavior, which may be affected by moisture ingression) are affected by adhesive film thickness, volume fraction, size and shape of the conductive filler, as well as uncured base adhesive viscosity, substrate and filler surface treatment and the applied pressure (during bonding and during conduction). The adhesive resistivity decreases precipitously above a characteristic filler volume fraction called the percolation threshold. In general, micron-sized metal fillers mixed in an adhesive (often an epoxy) resulting with different film thicknesses exhibit thickness thresholds for transition from three-dimensional conductivity to two-dimensional conductivity with considerable increases in thickness-direction (z-axis) resistivity when the film thicknesses are smaller than these threshold values. Recently, the use of conductive nanoparticles allowed decreases in percolation threshold levels as well as increases in mechanical strength and durability of ECA’s. Most ECA’s are supplied in liquid or paste form in varying viscosities and therefore, the method of their application also affects their performance. This work intends to provide an understanding of these effects on conduction behavior in (usually high-priced) equipment in which they are used.
... Infrared spectroscopy. PANI exists in three redox states: fully reduced leucoemeraldine, partially oxidised emeraldine, and fully oxidised pernigraniline 29 . These structures may be protonated or deprotonated, whether in an acidic or basic environment, respectively. ...
Electrically conductive scaffolds, mimicking the unique directional alignment of muscle fibers in the myocardium, are fabricated using the 3D printing micro-stereolithography technique. Polyethylene glycol diacrylate (photo-sensitive polymer), Irgacure 819 (photo-initiator), curcumin (dye) and polyaniline (conductive polymer) are blended to make the conductive ink that is crosslinked using free radical photo-polymerization reaction. Curcumin acts as a liquid filter and prevents light from penetrating deep into the photo-sensitive solution and plays a central role in the 3D printing process. The obtained scaffolds demonstrate well defined morphology with an average pore size of 300 ± 15 μm and semi-conducting properties with a conductivity of ~ 10–6 S/m. Cyclic voltammetry analyses detect the electroactivity and highlight how the electron transfer also involve an ionic diffusion between the polymer and the electrolyte solution. Scaffolds reach their maximum swelling extent 30 min after immersing in the PBS at 37 °C and after 4 weeks they demonstrate a slow hydrolytic degradation rate typical of polyethylene glycol network. Conductive scaffolds display tunable conductivity and provide an optimal environment to the cultured mouse cardiac progenitor cells.
... Scientists have been trying to increase the processability and solubility through employing different strategies such as co-polymerization [21] preparation of composites with different materials [22][23][24], using surfactants [25,26], etc. Different types of composites and hybrid materials have also been prepared using CPs with other polymers, papers, or hydrogels [21,[26][27][28]. Excellent environmental stability, good electrical properties, ease of synthesis and low monomer price make polyaniline (PANI) as one of the most promising CPs for practical applications [29][30][31][32][33]. In addition to the high electrical conductivity lightweight, high stress, low operational voltage and fast response time make PANI as a suitable candidate for developing efficient electrode materials for various electrochemical applications. ...
Flexible electrode materials are inevitable for high-end applications such as wearable electronics, implantable microelectrodes, artificial muscles, various sensors, and biomedical devices. A simple and easy method for large scale preparation of mechanically stable and flexible electrode material using PANI and PVA films is presented. The hybrid films prepared through the chemical coating of PVA using an in-situ chemical polymerization of aniline were highly electroactive and comprised of coral-like nanowires of PANI grown on the surface of PVA films resulting large surface area and high porosity as evinced from SEM studies. FTIR spectra showed characteristic bands of PANI and PVA. Bandgap energies estimated were consistent with the electrical conductivity of the films. The doubly coated film showed an electrical conductivity as high as 4.0 × 10⁻² S cm⁻¹. The high electrochemical activity studied through cyclic voltammetry was attributed to the easy diffusion of ions through the porous nanowires of PANI on the surface of the films. Thermal studies revealed that hybrid films are thermally more stable. The tensile strength of the hybrid films was comparable with that of pure PVA film in the dry state while in the wet state the single coated film was mechanically more stable. Sorption studies showed that the mass swelling ratio of the hybrid films was decreased due to the incorporation of PANI into the hydrogel matrix. As the films were mechanically stable and highly electroactive and can be cut into pieces of any desirable size and shape we propose that they can be used as active electrode materials for sensors, supercapacitors, actuators, etc.
... As mentioned above, PANI can be obtained either by in-lab synthesis or by purchase in the form of a conductive emeraldine salt. It can also be obtained as a conductive ink under the Panipol trade name, usually in the form of an approximately 5% green solution in xylene or another suitable solvent (Sancaktar and Liu, 2003). In addition, Panipol also supplies the PET film coated with this ink. ...
Barrier materials have wide applicability in both professional (military, medical, industrial) and non-professional (leisure and sports) fields. This paper focuses on the preparation of real conductive polymer (CP) sensors, for the study of the permeation of volatile toxic compounds through barrier materials. Use of such a CP sensor can help improve the quality of barrier materials used in protective clothing. Several types of platforms have been manufactured or purchased for use as comb sensors with different electrode dimensions, and a suitable method of applying the detection layer of conductive polymers (polyaniline and poly-pyrrole) has been developed. Prepared sensors were obtained using various technologies and were assessed not only for response to exposure to vapors of volatile toxic substances, but also for the possibility of their incorporation into a permeation cell, in order to expand the possibilities of using existing permeation devices. The resulting conductivity of the surface film ranges from 50 to 10,000 μS/cm. When exposed to ethanol vapors, the conductivity of the sensors dropped significantly and returned to the original value after exposure ended. The conductivity of the B12 CP sensor was in the range of 10-100 mS/cm and is considered the most valuable tested sensor. CPs deposited on this substrate have very high sensitivity in units of ppm (in special cases, even ppb) within the detection of analytes (in this case toxic vapors of ethanol, acetic acid) and the ability to return to initial (zero) conductivity.
Key words: Reversible conductive polymer-based sensor; QCM sensor platform; permeation cell; volatile toxic compounds; military textile barrier material.
... The irruption of intrinsically conductive polymers at the beginning of the millennium brought about some advancement in the field of ECAs, as highlighted in Chapter 8 of Li et al.'s 1 book, although the results obtained so far are less relevant than could be expected. Mir and Kumar 43 and Sancaktar and Liu 44 reported on the electrical conductivity and adhesive joint resistance of epoxy ECAs that included, respectively, electrically conducting polyaniline and polypyrrole. ...
On the basis of an analysis of results presented in the literature, the currently existing knowledge about relationships between the microstructural and physical properties of hard coatings is discussed. Particular emphasis is placed on the role of microstructural features, such as grain boundaries, nonequilibrium structures, impurities, and texture, in controlling the film hardness. On the basis of an analysis of results presented in the literature, the currently existing knowledge of electrically conductive adhesives (ECAs) is discussed. Particular focus is placed on the results obtained with ECAs that contain carbon nanotubes (CNTs) as conductive fillers. The review is divided in curable ECAs based on epoxy resins, and noncurable conductive hot melts and pressure-sensitive adhesives based on thermoplastic polymers. More literature results were found for epoxy/conductive filler ECAs than for other adhesives. Confirming the assessments made in a book by Li et al., which refers to nanotechnologies in ECAs, we found that only a reduced number of articles allude to polymer/CNT ECAs. Our analysis of the results includes a study of the balance between the viscosity, immediate adhesion, solidification process, electrical conductivity, and mechanical properties of the adhesives. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
... For example, based on simulation up to 10 5 particles in a composite, Rintoul and Torquato (1997) shown a percolation threshold at φ c = 0.2895±0.0005. Sancaktar and Liu (2003) showed a percolation threshold of 30% in a composite of emeraldine salt polyethylene powder dispersed in an adhesive polymer. ...
Problem statement: Thermodynamically, particles in composites will arrange in a way such that the Helmholtz free energy is minimized. However, even a single structure has the lowest free energy, it should not ignore the probability of other structures having larger energies to occur, although at small chances. Approach: All possible arrangements of particles in the composites, therefore, must be taken into account in the theory or simulation development. Results: The composite energy depends on the interaction between components in the composites. To consider the effect of interactions on energy, in this study we used a simple Ising model incorporated with the Bragg-Williams approximation. We used the model to predict the average packing fraction and the percolation threshold in composites as well as other quantities related to percolation phenomenon. Conclusion/Recommendations: We found several predictions that have not been reported by previous authors. This model can be important in the understanding conductivity development in electrically conductive adhesive composites.
... Epoxy/Ni conduc-tive adhesives can be used in integrated circuit (IC) packaging due to their lower cost than epoxy/Ag adhesives, with acceptable electrical conductivity, high thermal conductivity and low thermal expansion. Furthermore, silver-filled conductive adhesives suffer from the problem of silver migration, which may lead to failure in electrical conduction [24]. Works by Sancaktar and coworkers [25][26][27][28][29][30] showed that process conditions affect the mechanical performance of thermosetting adhesives in general, and mechanical as well as conductive performances of electrically conductive adhesives in particular. ...
Epoxy/nickel (Ni) adhesives can be used as integrated circuit (IC) packaging materials due to their lower cost than epoxy/silver (Ag) adhesives with acceptable electrical conductivity. In this work, yield behavior was studied for moderately filled bisphenol-A based epoxy/Ni suspensions (10–60 wt% of Ni). Effects of the preshear history, resin viscosity, temperature, particle size, solid loading, as well as different yield stress determination methods were investigated. The preshear effect manifests itself in successive shear rate sweeps with the same sample. Consequently, an initial shear rate sweep was employed to serve as preshear conditioning and obtain reproducible results on all samples. Shear thinning generally occurs for epoxy/Ni suspensions. The fractal dimension (Df) may be employed to describe these flocculated structures, and a higher Df value was observed for Epon815C/Ni system as compared to Epon830/Ni system. The Arrhenius equation describes the temperature dependence of suspension viscositys adequately. Incorporation of Ni nanopowder significantly reduces flow and the activation energy for yielding. The stronger van der Waals attractions created within the nanoparticles lead to larger yield stress. Also, different yield stress values are calculated using different determination methods.
... Electrically conductive adhesives have attracted significant attention during the last decades due to their increased usage in electronics industry to replace lead soldering [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18]. The major applications are die attachment, liquid crystal display and surface-mounted assembly of packaged components on printed wiring boards. ...
... In general, conductive adhesive pastes are formulated by mixing polymeric resins (such as epoxies, silicones and polyimides) and highly conductive metallic fillers. Theoretical and experimental studies have been performed on basic conduction mechanisms [2][3][4][5][6][7][8][9]; the effects of particle size, shape and type [4][5][6][7][8][9]; behavior in the bonded form [6,[8][9][10][11][12][13][14][15][16]; processing effects, such as pressure [2,4,9], adhesive film thickness [3,5,8], silver coating [4,5,7], anisotropic alignment of nickel particles in magnetic field [17]; as well as the possibility of using polymeric emeraldine salt particles as conductive fillers [18]. So far, the most popular conductive adhesive formulation has been silver (Ag) particles in epoxy resin [19][20][21][22]. ...
Epoxy/nickel adhesives can be used as integrated circuit (IC) packaging materials due to their lower cost than epoxy/silver adhesives with acceptable electrical conductivity. In this work, conductive epoxy/Ni adhesives were prepared by the solution method and filled into holes connecting the multilayers of a novel prototype designed for use in electronic components in circuit boards, in order to study the geometric effects on the prototype's electrical resistance. An empirical equation was obtained for the contact resistance (Rc) measured after cure. We also show that Ohm's law adequately describes the effects of the bulk adhesive resistance (Rb) on prototype's electrical resistance.
... Electrically conductive adhesives have attracted significant attention during the last decades due to their increased usage in electronics industry to replace lead soldering [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18]. Theoretical and experimental studies have been performed on basic conduction mechanisms [1][2][3][4][5][6][7][8]; the effects of particle size, shape and type [3][4][5][6][7][8]; behavior in the bonded form [5,[7][8][9][10][11][12][13][14][15]; processing effects, such as pressure [1,3,8], adhesive film thickness [2,4,7], silver coating [3,4,6], anisotropic alignment of nickel particles in magnetic field [16]; as well as the possibility of using polymeric emeraldine salt particles as conductive fillers [17]. ...
... Electrically conductive adhesives have attracted significant attention during the last decades due to their increased usage in electronics industry to replace lead soldering [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18]. Theoretical and experimental studies have been performed on basic conduction mechanisms [1][2][3][4][5][6][7][8]; the effects of particle size, shape and type [3][4][5][6][7][8]; behavior in the bonded form [5,[7][8][9][10][11][12][13][14][15]; processing effects, such as pressure [1,3,8], adhesive film thickness [2,4,7], silver coating [3,4,6], anisotropic alignment of nickel particles in magnetic field [16]; as well as the possibility of using polymeric emeraldine salt particles as conductive fillers [17]. Ni/epoxy conductive adhesives can be used in integrated circuit (IC) packaging due to their lower cost than Ag/epoxy adhesives, with acceptable electrical conductivity, high thermal conductivity and low thermal expansion. ...
Epoxy/nickel adhesives can be used as integrated circuit (IC) packaging materials due to their lower cost than epoxy/silver adhesives with acceptable electrical conductivity. In this study, stable and unstable capillary flows of highly-filled epoxy/Ni suspensions were investigated with and without cure at room temperature, via the capillary rheometry and syringe extrusion. Variations of the bulk electrical conductivity in these processes were discussed as well. Axial filtration of the polymer binder occurs under a static pressure for a cured epoxy/Ni system, Epon 815 C/Ni/diethylenetriamine (DETA) adhesive with 50 wt% of Ni in the syringe, resulting in an unstable flow and a cross-sectional filler concentration or electrical conductivity gradient. In dynamic capillary extrusion, lower resin viscosity and apparent shear rates enhance the flow instability and filtering of polymeric binder for epoxy/Ni suspensions with 75 wt% of Ni, thus facilitating a change in bulk electrical conductivity during processing. With increasing shear rates, both average force and force oscillation frequency increase. Incorporation of Ni nanopowder promotes a stable flow, yet the occurrence of agglomerates somewhat nullifies this advantage. Additionally, different rheological behaviors result as cure proceeds with different resins. Also, occurrence of the agglomerates leads to flow instability during processing with cure.
