Multi-material 3D printing of a soft pressure sensor

The emergence of smart technologies is spurring the development of a wider range of applications for stretchable and conformable sensors, as the design flexibility offered by additive manufacturing may enable the production of sensors that are superior to those produced by conventional manufacturing techniques. In this work, a multi-material 3D printing system with three extrusion heads was developed to fabricate a stretchable, soft pressure sensor built using an ionic liquid (IL)–based pressure-sensitive layer that was sandwiched between carbon nanotube (CNT)–based stretchable electrodes and encapsulated within stretchable top and bottom insulating layers. The sensor materials were modified in order to achieve 3D printable characteristics. The capability of the system was tested by printing structures made from three materials and a multilayer sensor via an extrusion-based direct-print process. Multi-material 3D printing of the sensor was successfully realized, as the sensing material retained its functionality once the printing process was complete.