Study into the application of single-wall carbon nanotubes in isotropic conductive adhesives

Isotropic conductive adhesives (ICAs) with stable contact resistance and high thermal conductivity are highly desirable. In this paper, a new ICA filled with silver fillers and single-wall carbon nanotubes (SCNTs) was developed. SCNTs were acidified in a mixture of 98% H₂SO₄ and 68% HNO₃ with a volume rate of 3:1 at 50 °C for 3 h. Carboxyl and hydroxyl groups were produced on SCNTs, and the purity of SCNTs also greatly improved. To prepare the ICAs, acidified SCNTs were firstly ultrasonically dispersed in acetone, then added into the matrix resin, and finally mixed with silver fillers. The bulk resistivity of the fabricated ICAs filled with silver fillers and acidified SCNTs was larger, their lap shear strength lower, their contact resistance stability improved, and their moisture absorption remained almost unchanged. In the curing process, the released heat was greatly reduced and transferred to the surroundings for good thermal conductivity of SCNTs, but the curing temperature was not affected. Therefore, acidified SCNTs can be used in ICAs, and in general, will create a good effect on ICAs.