Electrical and Mechanical Properties of Silicone Electrically Conductive Adhesive (ECAs) Filled Graphene-Carbon Black (GR-CB)

Abstract

ECAs were successfully introduced to replace hazardous lead-based solder, but their electrical conductivity and mechanical properties are limited. Hence, the incorporation of carbon black (CB) and Graphene (GR) filled silicone based ECAs with various ratios of GR and CB (0:0, 1:0, 0:1, 10:5, 5:10, 5:5, and 3:5) via solvent casting technique was investigated. The characterization of the conductive adhesive film using Fourier Transform Infrared Spectroscopy (FTIR) and electrochemical impedance spectroscopy (EIS) was investigated using the Nyquist plot and conductivity of silicone film. Meanwhile, the mechanical properties were measured using tensile and hardness tests. The appearance of a sharp peak in the FTIR spectrum confirmed that the interaction between the silicone matrix and GR-CB occurred (Si-CH3). The optimum ratio with the highest conductivity value, 7.98 10-8 Ω cm-1, was obtained by the synergistic effect of conductive fillers, which is GR with CB at 10:5 GR-CB ratio, which might be attributed to the synergistic effect from the filler. At the same time, tensile and hardness tests on silicone ECA samples exhibited that the optimum ratio of synergistic GR-CB was at 5:10 with the highest tensile strength, young modulus, elongation at break, and hardness with values of 1.16 MPa, 2.02 MPa, 25.64 mm, and 47.56, respectively due to the inherent stiffness of CB and GR. Finally, the electrical and mechanical properties revealed that adding GR and CB improved the conductivity, strength, and toughness of silicone ECAs composites, making way for electronic applications.