دانلود رایگان مقاله رسانایی در چسب رسانای سه تایی ناشی از نیروی موئینگی جاذب

Abstract

Materials with advanced conductive properties are in high demand to fulfill the requirements of energy transport in many fields. Here, we present a simple, efficient yet low cost method to produce highly conductive polymer based composites at low filler concentration of 10 vol%. A particle-wetting fluid as a secondary fluid is introduced to bridge plate-shape silver particles within an epoxy base. The electrical and thermal conductivity dependence on network structure in ternary silver adhesive presenting strong capillary attraction was first reported. Both electrical and thermal conductivities are greatly enhanced by introducing the secondary fluid at a low particle volume fraction of 10%. A non-monotonic dependence of the conductivities on secondary fluid content was observed. The maximum electrical and thermal conductivities correspond to the formation of full pendular network and funicular network, respectively. Gradually increasing the secondary fluid content leads to a microstructure evolution from highly dispersed particles, weak gel network, full pendular network, funicular network and ultimately to compact capillary aggregates network. Such structural transition appears to result from a pendular bridge formation and bridges coalescence. Face-face configuration of plate-shaped silver particles was observed in the pendular state. Taking account of the highly non-spherical shape of silver flake, a bridging gelation model is proposed to explain the underlying mechanism of microstructure transition.

4. Conclusion

This article reports the electrical and thermal performance of secondary fluid bridged ternary composites. A non-monotonic dependence of conductivities on secondary fluid content is observed. Morphological and rheological properties of ternary silver adhesives were studied to look into the microstructure. It is found that, with increasing the concentration of the secondary liquid IL, microstructure transits from a dispersed state, a weak gel network, full pendular network, funicular network and finally to compact aggregation. The microstructure transition highly depends on surface coverage and bridge saturation. The maximum electrical and thermal conductivities correspond to the turning point of elasticity and maximum yield stress, which are full pendular network and funicular network, respectively. Face-face configuration of platelet-shape particles bridging were imaged by TEM. A bridging gelation model is put forward to illustrate the structural transition.