Liquid-infused
slippery surfaces have replaced structural superhydrophobic
surfaces in a plethora of emerging applications, hallmarked by their
favorable self-healing and liquid-repelling characteristics. Their
ease of fabrication on different types of materials and increasing
demand in various industrial applications have triggered research
interests targeted toward developing an environmental-friendly, flexible,
and frugal substrate as the underlying structural and functional backbone.
Although many expensive polymers such as polytetrafluoroethylene have
so far been used for their fabrication, these are constrained by their
compromised flexibility and non-ecofriendliness due to the use of
fluorine. Here, we explore the development and deployment of a biodegradable,
recyclable, flexible, and an economically viable material in the form
of a paper matrix for fabricating liquid-infused slippery interfaces
for prolonged usage. We show by controlled experiments that a simple
silanization followed by an oil infusion protocol imparts an inherent
slipperiness (low contact angle hysteresis and low tilting angle for
sliding) to the droplet motion on the paper substrate and provides
favorable anti-icing characteristics, albeit keeping the paper microstructures
unaltered. This ensures concomitant hydrophobicity, water adhesion,
and capillarity for low surface tension fluids, such as mustard oil,
with an implicit role played by the paper pore size distribution toward
retaining a stable layer of the infused oil. With demonstrated supreme
anti-icing characteristics, these results open up new possibilities
of realizing high-throughput paper-based substrates for a wide variety
of applications ranging from biomedical unit operations to droplet-based
digital microfluidics.