Synthesis of highly conductive and mechanically strong silver coated silk bundles for flexible electronic applications

Paper in proceeding, 2016

Portable and wearable electronics that feature lightweight, highly compact and low cost can enable a wide variety of new applications, such as paper-like displays, smart clothing, stretchable solar cells, camera eyes and biomedical sensors. The applications for these types of system require conductive materials that are both highly conductive and mechanically robust enough to have large deformation stability. In this work, silver coated silk hybrid fibers were fabricated to meet the above requirements. As one of natural polymers used by human at the earliest stage, silk fiber has many advantages, such as light weight, good comfortability and mechanically robust. The chemical structure of silk fiber is composed of two main proteins, fibroin and sericin. Importantly, the sericin layer shows the special sol-gel property under temperature difference and therefore can be used for adhesion between the deposited silver nanoparticles and the surface of silk bundles. The silver coating layer on the surface of silk fiber can significantly improve the electrical conductivity of the hybrid structure to 1600 S/cm. Such a good conductivity is attributed to a complete silver shell structure. Importantly, the fabricated silver coated silk hybrid fibers demonstrated stable electro-mechanical properties under different structural deformations, including bending, compressing, and twisting. The observed stable and reliable electro-mechanical performance of silver coated silk hybrid fibers suggests the potential use of the material in future wearable and portable electronics.