Printing Conductive Micro‐Web Structures via Capillary Transport of Elastomeric Ink for Highly Stretchable Strain Sensors

Capillary transport-based printing dynamics are investigated using viscoelastic ink, polydimethylsiloxane (PDMS), to fabricate flexible and stretchable conductors. Without any microelectromechanical system techniques (e.g., molding), these soft and transparent structures can be obtained by fast and scalable steps. When attempted to draw mesh structures, microweb-shaped structures are spontaneously formed due to the low surface energy and flow ability of the viscous PDMS liquid. Unlike the conventional planar-shaped stretchable geometry, these microweb structures can be more stable because rounded edge area has advantages during stretching/releasing cycles as shown in previous research paper. After printing these microweb structures, functional silver nanoparticles are coated using polydopamine (PDA) solution. Polydopamine based on these structures shows very stable strain sensing cycles and highly durable results by adhesion test. As a result, this fabrication strategy can fabricate stretchable strain sensors with high and stable gauge factor by simple direct printing method, it is expected that it can have many applications such as electronic skin devices.