Capillary Interactions for Fabrication of Non-coalescent Liquidmetallic Nanospheres enabling Tuneable Gap-Plasmon based Mechanochromic Sensors

Gallium is a well-suited material for fabricating flexible photonic devices due to its fluidic and metallic properties. Localized Plasmonic resonance relies on fabricating metallic structures at the nanoscale with an extremely small gap between them, thus employing lithography or self-assembly techniques involving multiple reagents and process steps. In this work, we demonstrate a single-step and scalable fabrication of non-coalescent Ga Nanospheres on a biocompatible elastomeric substrate, Polydimethylsiloxane (PDMS), by exploiting the capillary interactions between liquid Ga and the uncured oligomers of PDMS. This approach enables the fabrication of multiple structural colors and mechanochromic sensors in a single deposition, owing to the active role played by PDMS in determining Ga nanostructures.