Fabrication of Metal Lines on Polymer Nanosheets by Inkjet Printing
Marin Okamoto, Mizuho Kurotobi, Kento Yamagishi,
Atsushi Murata, Toshinori Fujie, Eiji Iwase, Shinji Takeoka,
Development of wearable devices for collecting biological information is expected to broaden opportunities for people to be involved actively in their healthcare. However, conventional rigid electronics have difficulties in analyzing biological information accurately because of low conformability and risk of irritating the skin. To minimize discomfort during long-term use, wearable devices should be small, light, thin and flexible to secure the conformable contact to the tissues.
In our collaboration research, we focused on flexibility and adhesiveness of ultra-thin polymer films referred to as “polymer nanosheets” and envisioned to develop skin-attachable devices mounted on the nanosheets (Figure 1a). In this symposium, we will report three topics: 1) fabrication of nanosheets as flexible substrates for inkjet printing of silver nanoparticles, 2) evaluation of electrical property of silver lines printed on nanosheets, and 3) fixation of electric elements on the metal lines and operation of electric circuit laden nanosheets on the skin. Elastomeric nanosheets consisting of poly(styrene-butadiene-styrene) (SBS) were prepared as substrates of the device, which showed sufficient stretchability and conformability to the skin. Conductive lines were fabricated on the nanosheets after surface treatment by inkjet printing of silver nanoparticles aqueous dispersion. Furthermore, SBS nanosheets allowed for the encapsulation and physical fixation of electric elements by simply covering the elements with SBS nanosheets. It was proved that the electric circuit laden nanosheets could operate successfully on the skin surface (Figure 1b).
Wearable devices integrated with biological surface will make it possible to monitor physical condition without discomfort. Unperceivable wearable devices will be applied to various fields such as healthcare, welfare and sports science.
Figure 1. (a) Concept of a skin-contact electronic device constructed on a nanosheet. (b) An electric element (LED) fixed on skin covered with an SBS nanosheet.