Environmentally Friendly Graphene-Based Conductive Inks for Multitouch Capacitive Sensing Surfaces

Conductive graphene-based inks can be tailored for functional applications and, in particular, for printed electronics. Transparent, flexible, and easy printable materials are nowadays increasingly required for sensing applications. In this context, a capacitive multitouch sensing surface is developed using conductive graphene nanoparticles-based ink with carboxymethyl cellulose as a binder. The rheological properties of the ink are tailored to be printed by the screen-printing technique. The touchscreen is based on printed conductive lines and columns and thus the characteristics of the printed lines are optimized based on the line width and number of printing steps. The optimal printed conditions are 0.5 mm of width and five printing steps, leading to electrical resistance of 2.4 k omega. The screen-printed flexible touchscreen is composed of 40 columns x 28 rows. An electric circuit and a graphic interface are also developed leading to an 8 touchscreen with multitouch capabilities and fast signal processing.

Automated summary

The capacitive multitouch sensing surface developed using conductive graphene nanoparticles-based ink with carboxymethyl cellulose as a binder meets the increasing demand for transparent, flexible, and easy printable materials for sensing applications. The characteristics of the printed lines are optimized based on the line width and number of printing steps, with the optimal conditions leading to an electrical resistance of 2.4 k omega. The printed flexible touchscreen, composed of 40 columns x 28 rows, also features an electric circuit and graphic interface for multitouch capabilities and fast signal processing.