Seohan Yun1,Junyong Ahn1,Junyong Park1
Kumoh National Institute of Technology1
Seohan Yun1,Junyong Ahn1,Junyong Park1
Kumoh National Institute of Technology1
Since the 2000s, various types of dry adhesives have been proposed that mimic the hierarchical ciliary structure of gecko lizard’s paws. Recently, deviating from the research paradigm of simply mimicking the adhesive function, conductive dry adhesives made of nanocomposites in which conductive nanomaterials (e.g., CNTs and AgNWs) are dispersed in an elastomeric matrix have been developed. Attempts have been made to acquire various bio-signals by using them as skin-mountable dry electrodes, but their sensitivity is still limited due to the inherent trade-off relationship between electrical conductivity and adhesion in typical nanocomposites. Here, we propose a functionally layered, highly conductive, dry adhesive patch through rational design of spray coating and molding processes. Lateral collapse of the high aspect ratio ciliary structures, which frequently occur during spray coating of conductive dispersions, can be avoided through optimization of the process sequence. The dry adhesion and electrical conductivity of the patch are independently controlled by the aspect ratio of the ciliary structure and the amount of spray-coated AgNWs. We have finally succeeded in realizing a large-area (4 in<sup>2</sup>), defect-free dry adhesive patch that exhibits high electrical conductivity (< 100 ohms) and favorable normal adhesion (> 1.3 N/cm<sup>2</sup>) to human skin. Several proof-of-concepts utilizing the developed highly conductive dry adhesive patch will be presented.