Rapid Assembly of Large Scale Transparent Circuit Arrays Using PDMS Nanofilm Shaped Coffee Ring

Rapid and precise assembly of functional nanoparticles into well-defined structures in large scale is motivated by broad fields. In this study, large-scale transparent conductive circuit arrays are rapidly self-assembled by simply pipetting a gold nanoparticles suspension onto a PDMS nanofilm patterned substrate with distinct hydrophilic/hydrophobic areas. The solution firstly self-confines into predefined hydrophilic geometries, followed by assembly of nanoparticles into well-defined circuits with 1D patterns by coffee ring effect. Submicrometer height and submicrometer-to micrometer-width circuit arrays with various shapes are precisely generated by varying the PDMS nanofilm patterns. Thousands of circuits with different geometries are self-assembled simultaneously within 1 min. The conductive circuits show good optical transparency up to 95%. After being transferred into PDMS elastomer sheet by encapsulating, the circuits remain highly conductive during bending and stretching. With the advantages of high-throughput, equipment-free, scalability, and precise control, this technique will open an avenue for fabricating large-scale functional materials for applications in electronics, optoelectronics, and healthcare devices.