Zein-encapsulated liquid metal for in-situ stamping-sintering of flexible electronics

A novel metal ion-crosslinked zein-assisted stamp-sintering strategy is developed. • The metal ions-zein interactions enable the facile fabrication of LM patterns. • The excellent stamped LM circuits in flexible electronics are demonstrated. Liquid metals (LMs) have emerged as promising materials for flexible electronics owing to their excellent electrical conductivity and fluidity. However, their inherently high surface tension and surface oxide layer pose significant challenges to controlled processing and practical integration. Therefore, effective regulation of the interface of liquid metal particles (LMPs) is essential to improve their processability and interfacial compatibility. In this study, we developed a metal ion-crosslinked zein-assisted in situ stamping-sintering strategy utilizing zein as a surface functional agent to modify LMPs. This one-step process enables simultaneous LM patterning and in-situ sintering of the composite ink, eliminating additional activation steps. The resulting patterns exhibit robust adhesion to a wide variety of substrates, ranging from flexible to rigid, and from metallic to polymeric surfaces, attributed to the interfacial adhesion enabled by gallium ions released from the LM and the molecular structure of zein. By leveraging the advantages of the zein/LM ink and the stamp-printing technique, this system demonstrates considerable potential for broad application in next-generation flexible electronic systems. Download: Download high-res image (219KB) Download: Download full-size image