A flexible two dimensional force sensor using PDMS nanocomposite

- A transfer printing technique has been developed to pattern embedded carbon nanotubes onto PDMS.
- Patterns show good uniformity, forming an embedded CNT network.
- A highly flexible two dimensional force sensor has been demonstrated, showing the pressure map applied.

This paper presents a two dimensional force sensor fabricated on PDMS nanocomposite, with patterned carbon nanotubes (CNTs) acting as a force sensing unit. A novel fabrication method is composed of inkjet printing of CNTs onto polyethylene terephthalate (PET) and subsequent transfer of the CNT patterns to PDMS, resulting in a CNT-elastomer nanocomposite that is flexible and conductive. This approach allows patterning of a large-area conductive carbon nanotube pattern on PDMS. The achieved sheet resistance of the transferred patterns on PDMS was 1.2 kΩ/□ when printed 35 times, using an office inkjet printer. The fabricated sensor changes its resistance when force is applied perpendicularly to the sensor. A two dimensional force sensor, working on the principle of compression-induced deformation was fabricated and characterized with achieved resolution of four sensing cells per cm2. Additionally, we demonstrate a two dimensional flexible force sensor capable of creating a pressure map of the applied force. Together with inkjet printing, this pattern transfer process represents a highly effective patterning technique for embedding carbon nanotubes in PDMS.

103