Conductive ultra-flexible graphene-based films for electronic applications

One of the priority tasks in the development of flexible printed electronics is the creation of stable conductive 2D printing inks that can form highly flexible films. For instance, the development of wearable electronic devices requires materials that can withstand strain at the level of human skin elasticity. The structure, flexibility, and electrical properties of thin films of a graphene-based composite with the addition of the conductive polymer PEDOT:PSS and polyvinyl alcohol (PVA) were studied. The films were produced by 2D inkjet printing. The high conductivity of the samples is enabled by graphene because its content significantly exceeds the percolation threshold. It has been found that the addition of 5 wt% or more of PVA enables the film to retain its structure under strains of up to 40% (a bending radius of 0.13 mm). At the same time, the resistance change under such deformation strains declines significantly (∼3 times) compared to films without PVA. This is due to the formation of a flexible PVA network within the composite films. Moreover, due to this network, when no more than 30 wt% of PVA is added, the initial specific resistance remains within 20% of that of the original composite without PVA. Besides that, with the addition of PVA, the resistance remains low under repeated large mechanical strains (<i>ε</i> ≈ 17%). Thus, graphene-based composites with the addition of PVA are promising conductive materials for flexible and wearable electronics.