  Dynamically tunable nanoengineered structures for coloration show promising
applications in sensing, displays, and communication. However, their potential
challenge remains in having a scalable manufacturing process over large scales
in tens of cm of area. For the first time, we report a novel approach for
fabricating chromogenic nanostructures that respond to mechanical stimuli by
utilizing the fluidic properties of polydimethylsiloxane (PDMS) as a substrate
and the interfacial tension of liquid metal-based plasmonic nanoparticles.
Relying on the PDMS tunable property and a physical deposition method, our
approach is single-step, scalable, and does not rely on high carbon footprint
lithographic processes. By tuning the oligomer content in PDMS, we show that
varieties of structural colors covering a significant gamut in CIE coordinates
are achieved. We develop a model which depicts the formation of Ga nanodroplets
from the capillary interaction of oligomers in PDMS with Ga. We showcase the
capabilities of our processing technique by presenting prototypes of reflective
displays and sensors for monitoring body parts, smart bandages, and the
capacity of the nanostructured film to map force in real time. These examples
illustrate this technology's broad range of applications, such as large-area
displays, devices for human-computer interactions, healthcare, and visual
communication.
