Highly stretchable and conductive composite films with a multistoried film and pillar structure of gold on elastic substrates

A novel structure is designed for developing highly stretchable electrodes with a multistoried film and pillar (mFNP) structure of gold on an elastic substrate. The mFNP structure inspired by the percolation theory increases the conductive pathways in the stretchable electrodes considerably by connecting the gold layers with gold nanopillars and thus enhances the stretchability. The mFNP structure can be achieved by two methods. For the mFNP structure fabricated by the polycarbonate membrane mask method, the stretchability of the stretchable electrodes increases from 90% to 130% for single and double-storied structures, while for the porous layer method, the stretchability increases from 80% to 120% and 140% for single, double, and five-storied structures, respectively. The long term stability of the mFNP structure is tested by stretching cycles of 1000 times. In addition, stretchable microelectrode arrays based on this mFNP structure are developed to monitor the electrocorticogram (ECoG) signal of a rat with epilepsy successfully, as an effective and friendly bioelectronic interface. The novel structure improves the stretchability and also reduces the electrode size. This idea can be applied to other types of stretchable electronic design, enabling the stretchable electronics to wider applications.