Adhesion energy of as-grown graphene on copper foil with a blister test

Interfacial adhesion energy between as-grown graphene and its growth substrate reveals the nature of bonding, as well as provides insights for large-scale roll-to roll graphene transfer. In this study, a novel sample preparation scheme was developed and a unique quasi-static blister test was performed to measure the adhesion energy between as-grown graphene and its copper foil substrate. The copper foil was treated with acetic acid for 4 h, 24 h and 48 h prior to graphene growth. The corresponding adhesion energy was determined to be 0.74 ± 0.13 J/m2, 1.10 ± 0.16 J/m2, and 1.53 ± 0.11 J/m2, respectively. Longer exposures to acetic acid led to rougher copper foil surfaces, and thus higher adhesion energy. This trend is in contrast to that for transferred graphene, which has been found to have weaker adhesion to rougher substrates. The experimental results from this study suggest that the interaction between as-grown graphene and its seed layer was mainly due to van der Waals, instead of covalent or ionic bonds and that surface roughness of the growth substrate could be a significant factor in determining the as-grown graphene adhesion energy.

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