Image Gallery

Liquid Meniscus Spreading in a Micropillar Array
Description
The liquid meniscus spreading in a micropillar array is captured
using confocal microscopy. The interference pattern in the picture
indicates the thickness of the liquid. The dynamics of the liquid
front was investigated by studying the temporal evolution of the
shape of the meniscus.
Applications
Lab-on-a-chip, Thermal management, Water harvesting
People
Rong Xiao
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more

Nanofluid Volumetric Solar Absorbers
Description
Carbon-coated nano-sized (10-100 nm) solid particles are added to a
liquid heat transfer fluid (VP-1) to volumetrically absorb
concentrated solar radiation. These nanofluid absorbers promise
increased performance over surface absorbers by minimizing
temperature differences between the absorber and the fluid.
Emissive losses are consequently reduced through a behavior
referred to as "thermal trapping," which is essentially an
engineered "greenhouse effect." Receiver-side efficiencies are
predicted to exceed 35% when nanofluid volumetric receivers are
coupled to a power cycle and optimized with respect to the optical
thickness.
Applications
Concentrated Solar Power, Thermal Storage
People
Andrej Lenert
Read more

Planar Loop-type Heat Pipe
Description
Loop-type heat pipe with a fully planar evaporator, condenser and
reservoir for the integration into an air-cooled heat sink. The
planar geometry allows for the stacking of multiplue modular
condensers to meet a variety of cooling needs with low thermal
resistance.
Applications
Thermal Management
People
Arthur Kariya, Teresa Peters, Daniel Hanks, Martin Cleary

Thermal Management of GaN Electronics
Description
Gallium Nitride (GaN) electronics is one of the most exciting areas
of innovation in the microelectronics industry and one of the
greatest challenges in thermal management. We are using
electro-thermal device simulation, thermal modeling, and
micro-scale thermometry to understand the severity of the problem
in RF amplifier and power switching applications. We are planning
to develop advanced thermal management strategies based on high
thermal conductivity solids and liquid-vapor phase change to enable
record-breaking performance of GaN electronics.
Applications
Power electronics, RF/microwave power amplifiers (cellular
telephone base stations, military radar and communications)
People
Kevin Bagnall, Lenan Zhang, Stephen Walsh, Prof. Tomás Palacios'
Group (EECS, MIT)

Uni-directional Liquid Spreading of a Droplet
Description
A liquid droplet demonstrates uni-directional spreading behavior,
where the propagation is primarily in one direction and pinning
occurs in the other directions. This spreading behaviour is
distinct in comparison with other engineered surfaces owing to the
asymmetric geometry of the fabricated structures.
Applications
DNA microarrays, digital lab-on-a-chip, anti-fogging and
fog-harvesting, inkjet printing, thin-film lubrication and thermal
management
People
Kuang-Han (Hank) Chu, Rong Xiao Read
more

Thermal Enhancement of High-Temperature Heat Transfer Fluids
Description
Improving the poor thermal properties of molten salt heat transfer
fluids is crucial to increasing the efficiency of heat transfer at
high temperatures, such as in concentrated solar power plants.
Adding a small fraction of ceramic nanoparticles has been shown to
significantly increase the specific heat capacity of molten salts
and ultimately enhance the efficiency of concentrated solar power
plants. We believe the underlying mechanism for the improvement in
heat capacity is related to the liquid-solid adsorption energy at
the nanoparticle interface and are using a number of
characterization techniques to fully explore its thermal benefits.
Applications
Concentrated solar power, nuclear power, general thermal management
People
Matt Thoms

Condenser with copper sinter
Description
A sintered copper wick is incorporated into the condenser of a LHP
to stabilize the liquid-vapor interface using capillary forces.
Using this design, multiple planar condensers can be vertically
stacked in a loop heat pipe in spite of the uneven liquid pressures
caused by gravity.
Applications
Thermal management
People
Daniel Hanks, Arthur Kariya, Teresa Peters, Martin Cleary

Carbon Nanotubes for Capacitive Deionization (CDI)
Description
Capacitive deionization promises to be an energy-efficient water
desalination technology. In CDI, a voltage is applied across high
surface area electrodes. Salt ions adsorb onto the surface of the
electrode in the electric double layer (EDL), while the desalinated
water is then pumped through. Our research focuses on understanding
the ion transport mechanisms in these porous electrodes. We are
synthesizing vertically aligned carbon nanotube electrodes to
create an idealized geometry for experimentally studying the
diffusion and electrokinetics of ion transport.
Applications
Water desalination, supercapacitors
People
Heena Mutha

Dropwise Condensation on a Nanostructured Superhydrophobic Surface
Description
Environmental scanning electron micrograph (ESEM) of water
condensation on a nanostructured superhydrophobic surface showing
both partially wetting and suspended droplets (P = 1200 ± 12 Pa, Ts
= 282 ± 1.5 K). The nanostructured surface consists of an array of
equidistant superhydrophobic silicon nanopillars with diameters,
heights, and spacings of d = 300 nm, h = 6.1 µm, and l = 2 µm,
respectively.
Applications
Dropwise condensation, atmospheric water harvesting, anti-wetting
surfaces, high flux thermal management
People
Nenad Miljkovic, Ryan Enright Read more

Jumping Droplet Condensation
Description
When droplets coalesce on a superhydrophobic nanostructured
surface, the resulting droplet can jump from the surface due to the
release of excess surface energy. Here, we show that silanized
copper oxide surfaces created via a simple fabrication method can
achieve highly efficient jumping-droplet condensation heat
transfer. We experimentally demonstrated a 25% higher overall heat
flux compared to state-of-the-art hydrophobic condensing surfaces.
Applications
Enhanced condensation, anti-wetting surfaces
People
Daniel J. Preston, Nenad Miljkovic, Ryan Enright

Texture and Wettability
Description
Controlling wettability by varying surface chemistry and roughness
is of interest for a wide range of applications. It has been well
known that droplets on textured hydrophilic, i.e.,
superhydrophilic, surfaces form thin-films with near zero contact
angles. Here, we report an unexpected behavior where non-wetting
droplets (see above) are formed by slightly heating textured
superhydrophilic surfaces beyond the saturation temperature. This
phenomenon is distinct from the widely researched Leidenfrost and
offers an expanded parametric space for fabricating surfaces with
desired temperature-dependent wettability.
Applications
Microfluidics, drag reduction, self-cleaning, water harvesting,
anti-corrosion, thermal management
People
Solomon Adera, Rishi Raj, Ryan Enright

Liquid Evaporation on Superhydrophobic and Superhydrophilic Nanostructured Surfaces
Description
Environmental scanning electron microscope (ESEM) images of water
evaporation from superhydrophilic and superhydrophobic
nanostructured surfaces (P = 1400 ± 14 Pa, Ts = 283 ± 1.5 K). The
nanostructured surfaces consist of an array of equidistant silicon
nanopillars with diameter, height, and spacing of 300 nm, 7.5 µm,
and 2 µm, respectively. Capillary forces generated by the receding
meniscus on the hydrophilic surface result in liquid entrapment and
'kissing' pillars. These 'kissing' pillars allow for the formation
of rare metastable pinned droplets with highly irregular contact
lines.
Applications
Thermal management, elastocapillary micro/nanofabrication
People
Nenad Miljkovic, Ryan Enright
Read more

Liquid Freezing Dynamics on Hydrophobic and Superhydrophobic Surfaces
Description
False color environmental scanning electron microscope (ESEM)
images of water freezing on smooth and nanostructured hydrophobic
surfaces. The image shows a larger droplet undergoing rapid
freezing with notable protrusions.
Applications
Anti-icing surfaces
People
Nenad Miljkovic, Ryan Enright

Electrowetting-on-Dielectric Fluid Manipulation
Description
A MEMS vertical translation, or focusing, stage that uses
electrowetting-on-dielectric (EWOD) as the actuating mechanism was
developed. EWOD has the potential to eliminate solid-solid contact
by actuating through deformation of liquid droplets placed between
the stage and base to achieve stage displacement. Our EWOD stage is
capable of linear spatial manipulation with resolution of 10μm over
a maximum range of 130μm and angular deflection of approximately
±1°, comparable to piezoelectric actuators. We also developed a
model that suggests a higher intrinsic contact angle on the EWOD
surface can further improve the translational range, which was
validated experimentally by comparing different surface coatings.
The capability to operate the stage without solid-solid contact
offers potential improvements for applications in micro-optics,
actuators, and other MEMS devices.
Applications
Enhanced condensation, anti-wetting surfaces
People
Daniel J. Preston, Ariel Anders, Banafsheh Barabadi,Evelyn Tio,
Yangying Zhu, DingRan Annie Dai

Wettability of Graphene
Description
We investigated the effect of the background substrate on the
wettability of graphene. We performed dynamic contact angle
measurements and detailed graphene surface characterizations to
demonstrate that the defects present in CVD grown and transferred
graphene coatings result in unusually high contact angle hysteresis
even on highly smooth substrates. The advancing contact angle
measurements were observed to be independent of the number of
layers of graphene and in good agreement with corresponding
molecular dynamics simulations (see above) and theoretical
calculations. The contact angle with a monolayer graphene coating
on a substrate equaled the contact angle on highly ordered
pyrolytic graphite.
Applications
Advanced functional coatings, microfluidics, heat transfer
People
Rishi Raj, Shalabh Maroo
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more

Contact Angle Hysteresis on Structured and Superhydrophobic Surfaces
Description
Understanding the complexities associated with contact line
dynamics on chemically heterogeneous and superhydrophobic surfaces
are important for a wide variety of engineering problems. Through
careful dynamic contact angle experiments and thermodynamic
modeling, we demonstrated that contact line distortion (see above)
is the key aspect that needs to be accounted for in the dynamic
droplet models. On a surface comprised of discrete wetting defects
on an interconnected less wetting area, the advancing contact angle
was determined to be independent of the defects. Conversely, the
receding contact angle was heavily influenced by defects.
Applications
Advanced functional coatings, microfluidics, condensation,
anti-fogging and fog-harvesting, thin-film lubrication
People
Rishi Raj, Solomon Adera, Yangying Zhu, Ryan Enright
Read
more

Advanced Thermo-Adsorptive Battery Climate Control System for Electric Vehicles
Description
Biporous zeolite and metal-oxide frameworks promise high water
adsorption capacities at low relative pressures. Integrated in a
modular thermo-adsorptive battery with enhanced heat and mass
transfer characteristics, these materials are the basis of a novel
climate-control system that could significantly increase the
driving range of electric vehicles. Future implementations of the
technology could provide significant energy savings and noise
reduction for residential and commercial HVAC applications.
Applications
Automotive, residential and industrial HVAC systems
People
Sameer Rao, Hyunho Kim, Shankar Narayanan, Sungwoo Yang, Ian McKay

Evaporation-Induced Cassie-to-Wenzel Droplet Transition
Description
A superhydrophilic surface at room temperature can take on the
characteristics of a superhydrophobic surface by superheating the
substrate and allowing droplets to reside in the non-wetting Cassie
state on microstructured superhydrophilic surfaces due to an
evaporation-induced force that counters the wetting force.
Applications
Thermal Management
People
Rishi Raj, Solomon Adera

Surface structure enhanced microchannel flow boiling
Description
Description: Flow boiling is promising to cool high performance
electronic devices. However dry-out of the liquid film on the
channel wall due to flow instability can lead to significant
temperature excursion and oscillation. We show that incorporating
hydrophilic surface structures that are optimized to promote
capillary wicking can effectively maintain the liquid film in the
microchannel. As a result, the structures can suppress temperature
oscillations and enhance the critical heat flux.
Applications
Thermal management, electronics cooling
People
Yangying Zhu, Dion Antao, Jay Sircar, Sameer Rao

Planar Solar Thermophotovoltaic Device
Description
Optical image of a planar solar thermophotovoltaic (STPV) device
operating above 1000 °C, where thermal emission is well into the
visible spectrum. These elevated temperatures are reached via
concentrated solar power (CSP). Using vertically aligned multi-wall
carbon nanotube forests, this high intensity light is converted to
heat to drive narrow-band thermal emission from a photonic crystal
surface towards a photovoltaic cell.
Applications
CSP, power generation, thermal management
People
Andrej Lenert, David Bierman, Colin Kelsall

Oriented Zeolite on Support
Description
An oriented layer of MFI zeolites on a silicon support. We are
exploring the potential of zeolite-based membranes for their
potential in separating fresh water from salt water more
efficiently than current state-of-the-art polymeric reverse osmosis
membranes.
Applications
Desalination, Gas Separation
People
Tom Humplik
Read
more

Enhanced Nucleate Pool Boiling with Surfactants
Description
Surfactants are known to lower the surface tension of water, which
is an important property in boiling. In addition to bubbles
departing easier due to lower surface tension, surfactants can
increase the amount of nucleation and improve boiling performance
by up to 200%. In this photo, 0.133 mM of Triton X-114 in DI water
is boiling on copper foil at 2.5 W/cm2.
Applications
Nucleate pool boiling, industrial cooling, phase change
desalination
People
Jeremy Cho

High performance incandescent lighting
Description
A promising way to improve the efficiency of ILB is to tailor the
emitted spectrum using interference filters that reflect the
infrared energy back to the filament while transmitting the visible
light. At DRL, we are using a planar tungsten incandescent emitter
sandwiched between two interference filters optimized to reflected
infrared and transmit visible light for a wide range of angles. The
device currently shows close to 50% energy savings at a filament
temperature of 2800 K and a threefold increase in the visible light
output compared to a bare filament consuming an equal amount of
power. Although significant energy efficiency improvement has been
demonstrated, we are currently investigating (numerically and
experimentally) several challenges such as minimizing filament
evaporation and filter temperature while maximizing the geometrical
view factor and luminous efficiency. We hope that this work will
lead to an energy efficient incandescent light source that is also
commercially viable.
Applications
Lighting, thermal radiation management
People
Arny Leroy, Bikram Bathia, Ognjen Ilic

Optically Transparent Thermally Insulating Aerogels
Description
We have developed thermally super-insulating monolithic silica
aerogels which we have tailored to achieve high optical
transparency. The transparency of commercial silica aerogels has so
far been limited to <85% % due to the scattering of low
wavelengths from its relatively large pores, which results in
significant energy losses. In our lab, we have optimized the silica
aerogel fabrication recipe and processing conditions to achieve
pore sizes of 2-50 nm. Carefully tailoring the nanostructure of our
aerogel samples has allowed us to achieve solar-weighted
transmittance greater than 97% for a 3 mm thick sample (shown in
the image).
Applications
Concentrated Solar Power, Solar Water Heating, Industrial Process
Heating, Windows
People
Sungwoo Yang, Lin Zhao, Elise Strobach, Bikram Bhatia

Water nanodroplet on lipid monolayer
Description
Water nanodroplet on lipid monolayer simulated in a molecular
dynamics simulation. Here, boundary water molecules (black circles)
are detected and an elliptical curve fit (blue curve) is used to
determine the contact angle. The monolayer is oriented such that
its hydrophobic tails are pointing upward, hence the large contact
angle.
Applications
Tunable surface energy, electroporation, filtration, desalination
People
Shalabh Maroo, Jeremy Cho

PHUMP evaporator
Description
Cross sectional cut of a planar evaporator for a multiple-condenser
loop-type heat pipe. Multiple wicking layers are combined into a
single monolithic wicking structure. The sinter material,
thickness, and particle size for each layer was chosen based on its
combination of thermal conductivity, permeability, and capillary
pressure.
Applications
Thermal Management
People
Arthur Kariya




























Video Gallery
Magnetically Tunable Structures
Description
MIT engineers have fabricated a new elastic material coated with
microscopic, hairlike structures that tilt in response to a
magnetic field. Learn more about these structures here. Depending on the field's
orientation, the microhairs can tilt to form a path through which
fluid can flow; the material can even direct water upward, against
gravity.
Applications
Water-proofing, anti-glaring, "smart windows"
People
Yangying Zhu, Dion Antao, Rong Xiao
Advance Thermal Battery for electric cars
Description
We are building a compact and lightweight climate control system
called the advanced thermal battery (ATB) for electric vehicles.
The ATB eliminates the use of traditional vapor compression cycle
and PTC heaters by providing both heating and cooling to the
passenger cabin, and operates with minimal use of the on-board
electric battery. The replacement of conventional climate control
system with ATB can significantly enhance the driving range of an
electric vehicle.
Applications
Electric and Plug-in Hybrid Electric Vehicles, Mobile
Refrigeration, Space Heating and Cooling
People
Shankar Narayanan, Xiansen Li, Sungwoo Yang, Ian McKay, Hyunho Kim
Ode to Bubbles (Bubbles Dancing to Boiling Water)
Description
Turning boiling on and off on a surface with separately addressable
electrodes to the tune of Ode to Joy. The effect is achieved by
applying an electric field to boiling water with a small amount of
surfactant. Being able to turn bubbles on and off allows ten times
more energy to be transferred. Spatial and temporal control could
be useful electronic hot spot cooling applications. For more
information please see
MIT News article, MIT News video,
and
paper Excerpt from Beethoven's Symphony No. 9 taken from
Musopen.org (Public domain)
Applications
Power plants, desalination, electronics cooling
People
Jeremy Cho
K12 Outreach: Making Bioplastics
Description
As part of MIT's initiative to improve science, technology,
engineering and math (STEM) education at the K12 level (MIT-K12
project), we produced a video on bioplastics. We demonstrated how
to create bioplastics from simple household ingredients like potato
starch. We explained the mechanism of bioplastic formation as well
as biodegradation.
Applications
K12 education, sustainability
People
Heena Mutha, Jeremy Cho
Electrowetting-on-Dielectric Fluid Manipulation
Description
A MEMS vertical translation, or focusing, stage that uses
electrowetting-on-dielectric (EWOD) as the actuating mechanism was
developed. EWOD has the potential to eliminate solid-solid contact
by actuating through deformation of liquid droplets placed between
the stage and base to achieve stage displacement. Our EWOD stage is
capable of linear spatial manipulation with resolution of 10μm over
a maximum range of 130μm and angular deflection of approximately
±1°, comparable to piezoelectric actuators. We also developed a
model that suggests a higher intrinsic contact angle on the EWOD
surface can further improve the translational range, which was
validated experimentally by comparing different surface coatings.
The capability to operate the stage without solid-solid contact
offers potential improvements for applications in micro-optics,
actuators, and other MEMS devices.
Applications
Enhanced condensation, anti-wetting surfaces
People
Daniel J. Preston, Ariel Anders, Banafsheh Barabadi,Evelyn Tio,
Yangying Zhu, DingRan Annie Dai
Faster Dropwise Condensation
Description
We investigated droplet growth dynamics on superhydrophobic
nanostructured surfaces to elucidate the importance of droplet
morphology on heat and mass transfer. By taking advantage of
well-controlled functionalized silicon nanopillars, we observed the
growth and shedding behavior of suspended and partially wetting
droplets on the same surface during condensation. Environmental
scanning electron microscopy was used to demonstrate that initial
droplet growth rates of partially wetting droplets were 6 times
larger than that of suspended droplets.
Applications
Enhanced condensation, anti-wetting surfaces
People
Nenad Miljkovic
Jumping Droplet Condensation
Description
When droplets coalesce on a superhydrophobic nanostructured
surface, the resulting droplet can jump from the surface due to the
release of excess surface energy. Here, we show that silanized
copper oxide surfaces created via a simple fabrication method can
achieve highly efficient jumping-droplet condensation heat
transfer. We experimentally demonstrated a 25% higher overall heat
flux compared to state-of-the-art hydrophobic condensing surfaces.
Applications
Enhanced condensation, anti-wetting surfaces
People
Nenad Miljkovic
Harnessing the Full Potential of the Sun
Description
We are developing a solar thermal photovoltaic device -- a hybrid
solar thermal / photovoltaic technology that aims to take advantage
of both strategies. Incident sunlight is efficiently absorbed and
thermalized, driving narrow-band thermal emission at energies tuned
to just above the electronic band gap in the photovoltaic cell.
Applications
Solar energy harvesting for electricity
People
Andrej Lenergy, David Bierman, Youngsuk Nam









