4 research outputs found
Metasurfaces Leveraging Solar Energy for Icephobicity
Inhibiting
ice accumulation on surfaces is an energy-intensive
task and is of significant importance in nature and technology where
it has found applications in windshields, automobiles, aviation, renewable
energy generation, and infrastructure. Existing methods rely on on-site
electrical heat generation, chemicals, or mechanical removal, with
drawbacks ranging from financial costs to disruptive technical interventions
and environmental incompatibility. Here we focus on applications where
surface transparency is desirable and propose metasurfaces with embedded
plasmonically enhanced light absorption heating, using ultrathin hybrid
metal–dielectric coatings, as a passive, viable approach for
de-icing and anti-icing, in which the sole heat source is renewable
solar energy. The balancing of transparency and absorption is achieved
with rationally nanoengineered coatings consisting of gold nanoparticle
inclusions in a dielectric (titanium dioxide), concentrating broadband
absorbed solar energy into a small volume. This causes a > 10 °C
temperature increase with respect to ambient at the air–solid
interface, where ice is most likely to form, delaying freezing, reducing
ice adhesion, when it occurs, to negligible levels (de-icing) and
inhibiting frost formation (anti-icing). Our results illustrate an
effective unexplored pathway toward environmentally compatible, solar-energy-driven
icephobicity, enabled by respectively tailored plasmonic metasurfaces,
with the ability to design the balance of transparency and light absorption
Metasurfaces Leveraging Solar Energy for Icephobicity
Inhibiting
ice accumulation on surfaces is an energy-intensive
task and is of significant importance in nature and technology where
it has found applications in windshields, automobiles, aviation, renewable
energy generation, and infrastructure. Existing methods rely on on-site
electrical heat generation, chemicals, or mechanical removal, with
drawbacks ranging from financial costs to disruptive technical interventions
and environmental incompatibility. Here we focus on applications where
surface transparency is desirable and propose metasurfaces with embedded
plasmonically enhanced light absorption heating, using ultrathin hybrid
metal–dielectric coatings, as a passive, viable approach for
de-icing and anti-icing, in which the sole heat source is renewable
solar energy. The balancing of transparency and absorption is achieved
with rationally nanoengineered coatings consisting of gold nanoparticle
inclusions in a dielectric (titanium dioxide), concentrating broadband
absorbed solar energy into a small volume. This causes a > 10 °C
temperature increase with respect to ambient at the air–solid
interface, where ice is most likely to form, delaying freezing, reducing
ice adhesion, when it occurs, to negligible levels (de-icing) and
inhibiting frost formation (anti-icing). Our results illustrate an
effective unexplored pathway toward environmentally compatible, solar-energy-driven
icephobicity, enabled by respectively tailored plasmonic metasurfaces,
with the ability to design the balance of transparency and light absorption
Desublimation Frosting on Nanoengineered Surfaces
Ice
nucleation from vapor presents a variety of challenges across
a wide range of industries and applications including refrigeration,
transportation, and energy generation. However, a rational comprehensive
approach to fabricating intrinsically icephobic surfaces for frost
formationî—¸both from water condensation (followed by freezing)
and in particular from desublimation (direct growth of ice crystals
from vapor)î—¸remains elusive. Here, guided by nucleation physics,
we investigate the effect of material composition and surface texturing
(atomically smooth to nanorough) on the nucleation and growth mechanism
of frost for a range of conditions within the sublimation domain (0
°C to −55 °C; partial water vapor pressures 6 to
0.02 mbar). Surprisingly, we observe that on silicon at very cold
temperaturesî—¸below the homogeneous ice solidification nucleation
limit (<−46 °C)desublimation does not become
the favorable pathway to frosting. Furthermore, we show that surface
nanoroughness makes frost formation on silicon more probable. We experimentally
demonstrate at temperatures between −48 °C and −55
°C that nanotexture with radii of curvature within 1 order of
magnitude of the critical radius of nucleation favors frost growth,
facilitated by capillary condensation, consistent with Kelvin’s
equation. Our findings show that such nanoscale surface morphology
imposed by design to impart desired functionalitiesî—¸such as
superhydrophobicityî—¸or from defects can be highly detrimental
for frost icephobicity at low temperatures and water vapor partial
pressures (<0.05 mbar). Our work contributes to the fundamental
understanding of phase transitions well within the equilibrium sublimation
domain and has implications for applications such as travel, power
generation, and refrigeration
Desublimation Frosting on Nanoengineered Surfaces
Ice
nucleation from vapor presents a variety of challenges across
a wide range of industries and applications including refrigeration,
transportation, and energy generation. However, a rational comprehensive
approach to fabricating intrinsically icephobic surfaces for frost
formationî—¸both from water condensation (followed by freezing)
and in particular from desublimation (direct growth of ice crystals
from vapor)î—¸remains elusive. Here, guided by nucleation physics,
we investigate the effect of material composition and surface texturing
(atomically smooth to nanorough) on the nucleation and growth mechanism
of frost for a range of conditions within the sublimation domain (0
°C to −55 °C; partial water vapor pressures 6 to
0.02 mbar). Surprisingly, we observe that on silicon at very cold
temperaturesî—¸below the homogeneous ice solidification nucleation
limit (<−46 °C)desublimation does not become
the favorable pathway to frosting. Furthermore, we show that surface
nanoroughness makes frost formation on silicon more probable. We experimentally
demonstrate at temperatures between −48 °C and −55
°C that nanotexture with radii of curvature within 1 order of
magnitude of the critical radius of nucleation favors frost growth,
facilitated by capillary condensation, consistent with Kelvin’s
equation. Our findings show that such nanoscale surface morphology
imposed by design to impart desired functionalitiesî—¸such as
superhydrophobicityî—¸or from defects can be highly detrimental
for frost icephobicity at low temperatures and water vapor partial
pressures (<0.05 mbar). Our work contributes to the fundamental
understanding of phase transitions well within the equilibrium sublimation
domain and has implications for applications such as travel, power
generation, and refrigeration