Integration of f-MWCNT Sensor and Printed Circuits on Paper Substrate

The integration of sensors endows the packages with intelligence and interactivity. This paper is considered the most suitable substrate of smart packages because it is cost-effective, light, flexible, and recyclable. However, common concern exists regarding the reliability of paper-based system against bending and folding. In this paper, inkjet-printing of silver nanoparticles is used to form circuit pattern as well as interconnections for system integration on paper substrate. A humidity sensor made by functionalized multiwalled carbon nanotubes is fabricated on the same substrate. We evaluate the electrical performance of paper electronics and the reliability against bending and folding. The results reveal the capability and the limitation of paper electronics in terms of flexibility. The concept of a paper-based smart electronic system and the manufacture process are demonstrated by an interactive humidity sensor card prototype.