Roll to roll processing of ultraconformable conducting polymer nanosheets

Thin and compliant conductive materials and electronic devices that are able to stand as free-standing membranes or to conform to surfaces are relevant for the development of human-device interfaces and unperceivable skin-contact personal health monitoring systems. In this work, a roll-to-roll (R2R) process for the preparation of conductive polymer nanosheets on large areas has been developed in view to move such technology towards real-world applications. R2R conductive nanosheets are obtained as free-standing structures through release from a temporary substrate and then transferred in conformal contact with any target surface with arbitrary shape, curvature and surface topography (including biological tissue such as skin). A specific high-conductivity formulation of PEDOT:PSS has been optimized for skin-contact applications, by making use of butylene glycol (BG) as a dopant: a dermatologically approved ingredient. The R2R nanosheets were tested as unperceivable surface electromyography electrodes able to record muscle-electrical activity. The present R2R process has advantageous properties such as continuous, high throughput printing on large area rolls, cost-effectiveness, speed of execution and use of industry-ready/mass-scale manufacturing technology.