Onset of electrical conduction in isotropic conductive adhesives: a general theory

Mikrajuddin, A.; Shi, Frank G.; Chungpaiboonpatana, S.; Okuyama, Kikuo; Davidson, C.L.; Adams, Judith

doi:10.1016/s1369-8001(99)00035-9

Cited by 57 publications

(58 citation statements)

References 29 publications

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“…At high volume fraction of silver particles, the conductivity becomes high due to the larger continuous contacts produced among the silver particles. 2,13,19) However, at the range of high volume fraction (92 to 94 mass% in this study), it also inevitably increases the contact resistance, thus resulting in a much smaller decrease of electrical resistance. 24) Therefore, the most suitable silver content in CCA is determined to be around 92 mass% (CCA3) in this study.…”

Section: Conductive Adhesivesmentioning

confidence: 70%

“…That is, as the filler concentration in the polymer matrix is varied, the conductivity exhibits an insulator-to-conductor transition that is interpreted as a percolation threshold. [12][13][14] However, the conducting filler metals (micro size) such as, silver, gold, and copper 15) in conventional conductive adhesives are not dissolved in the polymer matrix at curing temperature (423 to 473 K). Accordingly, the current in conventional conductive adhesives passes by the formed small contact electrical path and by tunneling effect, as illustrated in Fig.…”

Section: Introductionmentioning

confidence: 99%

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Electrical Characteristics of a New Class of Conductive Adhesive

et al. 2005

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Conventional conductive adhesives are composed of micro-sized filler metal and polymer matrix. Currently, the conductivity of conventional conductive adhesives is generated by small contact points formed among the particles during the curing process and by the tunneling effect. Therefore, conventional conductive adhesives generally exhibit higher electrical resistance than metal solder materials. In this study, a new class of conductive adhesive, composed of nano-particles and micro-particles in epoxy, was developed to improve electrical conductivity. This study used four conventional conductive adhesives (CCA1 to 4) and three hybrid conductive adhesives (HCA1 to 3). Scanning electron microscopy (SEM) observation was used to investigate the configuration of nano-particles and micro-particles. The electrical resistance of HCA1 to 3 was investigated and compared to CCA1 to 4 using a four-point probe method. When 2 mass% of nano-particle content was added to the micro-particle (HCA1), the electrical resistance decreased compared to CCA3. At 4 mass% of nano-particle content (HCA2), the electrical resistance value was similar to CCA3. However, at 8 mass% of nano-particle content (HCA3), the electrical resistance continued to increase, and exceeded that of CCA3.

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Section: Conductive Adhesivesmentioning

confidence: 70%

Section: Introductionmentioning

confidence: 99%

Electrical Characteristics of a New Class of Conductive Adhesive

et al. 2005

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“…The factor   / plays similar role with  in the electric current flow. This similarity allows the adoption of equation that explains the effective conductivity in a conductive fillers/insulating matrix composite to be used for calculating the effective permeability of porous materials [16][17][18].…”

Section: Resultsmentioning

confidence: 99%

Fabrication of Microporous Water Filter Using Titanium Dioxide Particles, Silica Particles, and Polyethylene Glycol

Priatama¹,

Abdullah²,

Khairurrijal³

et al. 2010

itbj.eng.sci.

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Abstract. We report the fabrication of microporous filter for use in filtering both inorganic and organic substances from liquid materials. Titania (TiO 2 ) anatase was used as the main material for this filter. Polyethylene glycol (PEG) with average molecular weight of 20,000 was also used as additive to control the formation of pores, especially pore sizes. The mixture of titania and PEG was pressed into cylindrical tablet shape at room temperature and then simply heated inside a furnace up to temperature where the PEG decomposed into gas to leave only connected titania particles. The use of titania as base material for the filter allows the organic substances that trapped inside the filter pores to be easily removed by heating up the used filter at above decomposition temperature of the trapped organics. We also made other filter by adding small amount of silica (SiO 2 ) particles to reduce the size of the pores as well as to improve the mechanical strength. We observed that filters containing silica particles, with smaller in size compared to titania, resulted in better mechanical strength, smaller in pore sizes and better filtering results in term of turbidity and dissolved oxygen (DO) content. This method is potential for development of larger scale and cheaper water filters for use in various applications.

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“…Previously we have proposed a modified effective medium approximation to calculate such conductivity using the following Eq. 9 (Mikrajuddin et al, 1999;Abdullah et al, 2003): ) with P pp is the probability of particle-particle contact P pm , is the probability of particle matrix contact, P mm , is the probability of matrix-matrix contact, where P pp + P pm + P mm = 1, σ pp is the conductivity at contact point between particles σ pm , is the conductivity between contact point between particle and matrix σ mm , is the conductivity at contact point between matrix elements (the conductivity of adhesive) and σ e is the effective conductivity of the composite.…”

Section: Methodsmentioning

confidence: 99%

“…Some authors reported that the percolation threshold depends on the coordination number as v c = D/γ(D-1) with D is the dimensionality (2 for two dimensions and 3 for three dimensions) (Chelidze, 1982). Using the modified effective medium approximation, we previously reported that the percolation threshold occurs at c v f / 2 / = γ , with f is the packing fraction (Mikrajuddin et al, 1999) and by adopting a theory for sol-gel development in polymerization for describing the connectedness of particles in composites, we have predicted the occurrence of the percolation threshold at vc = f/ (γ-1) (Mikrajuddin et al, 2001). In most theories and simulations, the arrangement of particles in the composite was taken as an initial axiom.…”

Section: Introductionmentioning

confidence: 99%

Ising Model for Conductive Percolation in Electrically Conductive Adhesives by Considering Random Arrangement of Conducting Particles

A.¹

2012

American Journal of Applied Sciences

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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 BraggWilliams 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.

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Onset of electrical conduction in isotropic conductive adhesives: a general theory

Cited by 57 publications

References 29 publications

Electrical Characteristics of a New Class of Conductive Adhesive

Electrical Characteristics of a New Class of Conductive Adhesive

Fabrication of Microporous Water Filter Using Titanium Dioxide Particles, Silica Particles, and Polyethylene Glycol

Ising Model for Conductive Percolation in Electrically Conductive Adhesives by Considering Random Arrangement of Conducting Particles

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