Synthesis and Characterization of Graphene Nanoplatelets Fabricated by Electrochemical Exfoliation Method for Conductive Adhesive

抄録

Graphene nanoplatelets (GNPs) were synthesized by an electrochemical exfoliation method. Four various conditions of the electrochemical exfoliation process: (I) 1 M NaOH with 4 V, (II) 0.5 M H₂SO₄ with 5 V, (III) a mixture of 1 M NaOH and 0.5 M H₂SO₄ with 5 V, and (IV) a two-step process of 1 M NaOH with 4 V and 0.5 M H₂SO₄ with 5 V, were compared. The as-synthesized GNPs obtained from all conditions were characterized by Raman spectroscopy and X-ray diffraction. The two-step process provided the GNPs with the low defect concentration and the lowest number of layers. Moreover, confirmed by field emission scanning and transmission electron microscopes (FE-SEM and TEM), the GNPs obtained from the two-step process were multilayer graphene. The GNPs obtained from each condition were added into an ultraviolet-cured acrylate adhesive to fabricate electrically conductive acrylate adhesive (ECAA). The GNPs acted as fillers to play an important role in conducting the electrical network of the ECAA without any other additive. The van der Pauw method was conducted to measure the electrical resistivity of the ECAA. The ECAA, containing 5 wt% of the obtained GNPs from the two-step process, had the lowest resistivity when compared to the ECAA which contained the obtained GNPs from other conditions. We found that the percolation threshold of the ECAA, containing the obtained GNPs from the two-step process, was at 3.26 wt%. Last, 6.92 wt% of the GNPs reached the lowest resistivity at 1.09 Ω·cm.