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

Abstract

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 kΩ. The screen‐printed flexible touchscreen is composed of 40 columns × 28 rows. An electric circuit and a graphic interface are also developed leading to an 8” touchscreen with multitouch capabilities and fast signal processing.

Multifunctional Touch Sensing and Antibacterial Polymer‐Based Core‐Shell Metallic Nanowire Composites for High Traffic Surfaces

“…Different multitouch capacitive sensor devices have been developed with a variety of polymer‐based composites, mainly based on their easy processing by additive manufacturing and integration into functional devices, [ 41 ] nonetheless the present work introduces, together with the excellent touch sensing performance, the antibacterial characteristics necessary in high traffic surfaces.…”

Transparent Piezoelectric Polymer-Based Materials for Energy Harvesting and Multitouch Detection Devices

“…In the present case, commercial sheets of PVDF have been used for convenience, but it is important to notice that PVDF with performance similar to that of commercial ones can be obtained by screen-printing, on the basis of environmentally friendly solvents . Thus, it is relevant to notice that the device presented in the present work can be fully screen-printed.…”

Recent Advances of Capacitive Sensors: Materials, Microstructure Designs, Applications, and Opportunities

“…Specifically, the electrode arrays for capacitive sensors were printed on indium tin oxide (ITO)patterned PET thin film, which endows the touch screen with thinner configuration and potential to replace traditional input devices including keyboards and mice [174] with better humancomputer interaction. Similarly, Franco et al [175] used the screenprinting technology to fabricate a transparent and flexible capacitive multitouch sensing surface with graphene-based conductive inks as electrodes. As shown in Figure 19B, there was a noticeable capacitance change with touch between finger and screen.…”

“…In their work, the biodegradable carboxymethyl cellulose served as blinder, contributing toward the environmental conservation. [175] Ideally, touch screen sensor arrays are self-healable, as replacing a cracked screen with a new one is always costly. Over the past a few years, Li et al [176] designed a transparent capacitive touch screen based on a healable silver nanowire-polymer composite electrode (Figure 19C).…”