BIOMIMICRY
NICK MOREY | F2023
TABLE OF CONTENTS I. II.
DISTILL BIOLOGIZE
III. IV. V.
TRANSLATE EMULATE EMULATE & DISCOVER
3- 9 8 - 18 19 - 23 24 - 31 32 - 40
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DISTILL
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BUILDING SKIN ISSUES Buildings leak (floods, rain, etc.) Common facades keep fresh air out Facades absorb heat or reflect it onto the surroundings Buildings catch wind and get buffered Facades are stagnant and can’t change Facades are heavy Building skins can’t adjust to their surroundings These problems exist in all buildings, but they are especially prominent in high rises/ commercial buildings
Buildings are buffered
Buildings are
Buildings keep stuffy air
by high winds
susceptible to floods/
in and fresh air out
leaks
It would be interesting to investigate the water/vapor barrier to find a better solution to both protect from water and allow air flow. Why? Because we often block airflow in order to block water, or prioritize airflow over moisture control. I would like to find a solution for both.
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GROUP DISCUSSION WHY IS THIS AN ISSUE? Flooding ruins the human experience of buildings, mold and health concerns need to be adressed, flooding and stagnant air requires HVAC and/or dehumidifiers to be run (using energy), the structures and finishes of buildings are damaged by flooding and mold, the exterior of buildings deteriorates quickly, windows get damaged by condensation, and the water that is removed is wasted. WHAT ELSE COULD POTENTIALLY BE SOLVED? Energy could be conserved, the risk of mold would be reduced, the washout of landscaping would be reduced, the maintenance and cleaning of windows could be made easier, water shedding would increase the longevity of materials, it could give greater control of rain water, it would reduce condensation and make floors less slick (increasing safety), would help reduce odors and smells in rooms. WHAT SOLUTIONS HAVE BEEN STARTED TO SOLVE THIS? Scented HVAC systems, San Antonio Pavillion (Confluence Park).
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https://www.drylok.com/inspiration/blog/6-steps-for-waterproofing-during-build
Projects currently use waterproofing membranes that are effective at reducing water infiltration, but trap air (and any infiltrated water) in the building/materials. Landscaping and directing water away from the building is very helpful, and doesn’t affect air circulation.
https://www.cdc.gov/coronavirus/2019-ncov/prevent-getting-sick/improvingventilation-home.html
Opening windows and doors is the best way currently to promote airflow without using energy, but this allows water/moisture particles into the building as well, and increases the heating and cooling costs. Using fans and air purifiers improves air quality, but uses energy.
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Breeze blocks are decorative masonry units that allow airflow from the outside while still providing privacy, but they provide no moisture barrier.
https://www.archdaily.com/catalog/us/ products/33897/breeze-blocks-jonite/338656?ad_ source=neufert&ad_medium=gallery&ad_ name=next_image
Most products available either admit air and moisture, or block both. WHAT DO I WANT MY DESIGN TO DO? I want to create a system to “breathe” and allow air into the building while blocking moisture flow.
ADDITIONAL BENEFITS
https://www.introba.com/news/breathable-buildings
People spend too much ime in their office, so air quality needs to be higher. People want healthier environments, which would cut down on healthcare costs. Saving energy could help with global warming.
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https://www.introba.com/news/opinion-breathable-buildings
The energy savings that would come from natural ventilation would be massive, but filtration (or an artificial ventilation system) is surely needed for wildfires, pollution, etc.
https://issuu.com/deepgreenengineering/docs/impact_fund_breathable_ buildings?fr=sODYwNDU4NDUwMDc
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https://issuu.com/deepgreenengineering/docs/impact_fund_breathable_ buildings?fr=sODYwNDU4NDUwMDc
A lot of natural ventilation involves simply opening doors and windows, or automating them for certain times. This allows an influx of fresh air, but also admists moisture, pollen, and other “junk”
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BIOLOGIZE
HOW MIGHT WE CONTROL WATER AND AIRFLOW BETTER IN RESIDENTIAL BUILDINGS IN THE MIDWEST?
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WHY? The Midwest experiences extreme weather conditions: humid, hot summers, torrential downpours, tornadoes and high winds, and snow and freezing temperatures in the winter. Any of these can be detrimental to a building, but combined, they create a variety of challenges that require an array of solutions to solve. If there was one product that could handle all or most of these issues, it would make buildings much more resilient.
FUNCTIONS RELATED TO THE ISSUE: • Water proofing • Interacting with wind and air • Breathing • Adapting from wet to dry environments • Regulating temperature • Regulating humidity • Gills?
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CONTEXTS: • Flooding • Rain • Heatwaves • Strong winds • High and low humidity • Coastal areas • Arid and desert environments DESIGN QUESTIONS: • How does nature EXPEL WATER? • How does nature COLLECT WATER? • How does nature UTILIZE HUMIDITY? • How does nature THRIVE IN DRY ENVIRONMENTS? • How does nature THRIVE IN HOT ENVIRONMENTS? • How does nature WITHSTAND HIGH WINDS?
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HOW DOES NATURE...
EXPEL WATER?
IGUANAS excrete excess water from a gland on the ventral side of their femur through tubes that end in a series of pores. https://asknature.org/strategy/pores-expel-fluid/
CRANE FLIES are covered with thousands of tiny hairs that create longitudinal ridges across their bodies that essentially make their entire bodies hydrophobic. https://asknature.org/strategy/hairs-repel-water/
DOGS and other mammals quickly shake the water and moisture off of their fur to help protect its insulating properties. This method helps conserve energy and counters the surface tension and capillary action with centripital force. https://asknature.org/strategy/body-oscillation-to-dry-off/
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OTTERS and all fur-bearing animals use two types of hair to keep the animal warm and dry, even when they are in cold water. Guard hairs are long and extend over underhairs, which are shorter and denser (usually about 3 underhairs per guard hair). The underhair has scales on the cuticle, which interlock with each other to resist water and create an insulating layer of air. These animals have flatter and denser hair, which helps resist water better than fluffy hair. Otters also have unique ear-flaps that can be closed to prevent water entering their ears.
https://asknature.org/strategy/fur-keeps-heat-in-and-cold-water-out/
FUNGI have hydrophobin proteins that reduce the surface tension of water. Because they grow at such a small scale, the surface tension in water can prevent them from continuing growth. Hydrophobin proteins dissolve in water, but have an acidic, hydrophobic face that weakens the surface tension. These proteins align themselves to orient the hydrophobin faces outward, which keeps them dry and aligned.
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https://asknature.org/strategy/proteins-reduce-surface-tension/
SALVINIA WATER FERNS are covered with hair groupings that resemble wire whisks. These hairs are hydrophobic except for the tip, which is hydrophilic and attracts water. This creates a small air pocket, which is part of a larger system that creates a layer of air over the surface, allowing the leaf to remain bouyant, even when it is fully submerged.
https://asknature.org/strategy/leaf-structure-retains-air-layer-underwater/
LICHEN have pores that encourage water to roll off it, and they allow gas exchanges even when it is completely submerged. The rough structure of the lichen keeps the water on the top layer, and creates “channels” for gas to be exchanged.
https://asknature.org/strategy/rough-hydrophobic-surface-allows-gas-exchange/
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FILTER OUT WATER? When CAMELS exhale, the air they breathe is cooled, which condenses water in their nasal cavities, allowing them to stay more hydrated. They only do this at night, because during the day it would mess up their heat regulation.
https://asknature.org/strategy/nasal-surfaces-remove-water-vapor/
SANDGROUSE are native to water-scarce areas such as Africa and Asia. As their chicks are growing, the male sandgrouse will absorb water with the inner four-fifths of their feathers, which it then transports up to fifteen miles to water its chicks.
https://asknature.org/strategy/ultra-absorbent-feather-structure-carries-water-2/
Some plants in the BROMELIACEAE family collect water into a central “tank” where it can be better utilized. Their leaves are cupped, which allows the water to drain with gravity, and the surface of the leaves is covered with cells called
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trichomes. The trichomes have tiny hairs that help collect water, but are coated in hydrophobic wax crystals to allow the water to flow down the leaf. https://asknature.org/strategy/leaves-capture-water-2/
ADAPT TO HUMIDITY? The SOUTH AMERICAN GRASS-CUTTING ANT colonies build thatched nests on the surface of the ground, rather than below it. The thatching and materials (plant fragments and debris) help insulate the nest and keep the humidity stable, because the material is slow to change temperature. This allows the ants to cultivate fungus to feed to their young. https://asknature.org/strategy/colonies-maintain-temperature-and-humidity/
Many members of the Legume family have a HILAR VALVE to regulate humidity in their seeds. They react not only to the amount of humidity in the air, but also to the rate at which the humidity changes, as a sudden increase or decrease would be catastrophic to the seed. https://asknature.org/strategy/valve-regulates-water-permeability/
FROGS AND TOADS are prone to fungal infections (similar to athelete’s foot) because they live in such humid environments. The Anuran family of frogs in Panama release compounds called viscosin that help stop the spread of fungi. Vicosin are bacteria that attack other bacteria by creating holes in the cell membrane, which causes a fatal chemical imbalance in the bacteria. https://asknature.org/strategy/bacteria-on-frog-skin-releases-anti-fungal-compounds/
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SURVIVE IN THE DESERT? Some DESERT SNAILS use layered shells with insulating air pockets to stay cool as ground temperatures reach onehundred-fifty degrees Fahrenheit in the desert.
https://asknature.org/strategy/shell-protects-from-heat/
The genus Selaginella, which includes the CLUBMOSS PLANT, can dry and rehydrate multiple times because it has vacuoles that are filled with tannin colloids instead of ions. This keeps the cells from changing size too rapidly. https://asknature.org/strategy/plants-survive-repeated-drying-and-rehydration/
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TRANSLATE
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NATURAL MODELS FOR EXPLORATION: SALVINIA WATER FERN I chose these plants because I think their ability to create a natural air layer to protect the surface of the leaf has a lot of potential for protecting buildings from floods. The use of both hydrophobic and hydrophilic properties is extremely interesting and exciting.
The surface of the leaf is filled with groups of tiny hairs that form a “whisk” shape. The top is hydrophilic and attracts a drop of water, while the rest is hydrophobic and creates a layer of air bubbles. This layer of air protects the leaf and keeps it bouyant during a flood, allowing it to slough off the dirt and water.
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OTTERS I want to investigate otters more because they’re very similar to the Salvinia Ferns in that they keep a layer of air for protection. Although they spend a huge amount of time in the water, their bodies are able to stay dry thanks to their layered fur. Long guard hairs extend out over shorter and denser underhairs. The underhairs have small scales at the cuticle, which interlock and trap air to insulate the otter’s body.
SOURCES TO REFERENCE SALVINIA WATER FERNS Cerman, Zdenek, et al. “Dry in the Water: The Superhydrophobic Water Fern Salvinia – a Model for Biomimetic Surfaces.” Functional Surfaces in Biology, Springer, Dordrecht, 2009, pp. 97–111. He, Qingqing, et al. “3D Printing of Salvinia Water Fern-Inspired Superhydrophobic Structures .” Proceedings of ASME 2022 17th International Manufacturing Science and Engineering Conference (MSEC2022): June 227-July 1, 2022, West Lafayette, Indiana, The American Society of Mechanical Engineers, New York, NY, 2022. Konrad, Wilfried, et al. “The impact of raindrops Salvinia molesta leaves: effects of trichomes and elasticity.” Journal of The Royal Society Interface, vol. 18, no. 185, 15 Dec. 2021, https://doi. org/10.1098/rsif.2021.0676.
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Xiang, Yaolei, et al. “Superrepellency of underwater hierarchical structures Salvinia leaf.” Proceedings of the National Academy of Sciences, vol. 117, no. 5, 2020, pp. 2282–2287, https://doi. org/10.1073/pnas.1900015117. OTTERS Ivlev, Yu. F. “Biomechanical Analysis of Fur as a Tool for Study of Thermal Insulation in Semi-Aquatic Mammals.” Biology Bulletin, vol. 46, no. 7, 21 Feb. 2020, pp. 763–779, https://doi.org/10.1134/ s1062359019070057. Yochem, Pamel K. “Hair and Fur.” Encyclopedia of Marine Mammals (Second Edition), edited by Brent S. Stewart, Academic Press, 2009, pp. 529–530. OSU FACULTY OF INTEREST
DR. MARK FISHBEIN Department of Plant Biology and Ecology, and Evolution mark.fishbein@okstate.edu Dr. Fishbein is the Department Head of Plant Biology, Ecology, and Evolution. I have had a few conversations with him in the past and he is amazing at explaining complex ideas in easy to understand ways, so I think he would be great to work with and learn from.
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DR. ANN PRICE Department of Plant Biology and Ecology, and Evolution ann.price@okstate.edu Dr. Price teaches Plant Physiology, which looks at “plant subcellular structure, water relations, water absorption...” and other subjects. I think this class would be very helpful in understanding how the Salvinia Water Fern interacts with water.
DANIEL MOEN Department of Integrative Biology daniel.moen@okstate.edu Professor Moen focuses on evolution, and I think it would be extremely interesting to see how otters and other semi-aquatic mammals have evolved to stay warm and dry in cold water. Additionally, his research combines fieldwork with museum data, which could help discover even more useful information.
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EMULATE
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DRAW THE BIOLOGICAL PROCESS TO BE EMULATED
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https://onlinelibrary.wiley.com/doi/full/10.1002/smll.202003425
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The layer of air pulls the leaf to the surface when it is submerged.
https://www.researchgate.net/figure/Leaf-of-Salvinia-molesta-floating-on-water-The-leaf-surface-isdensely-covered-with_fig1_263116046
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FIND KEYWORDS • HYDROPHOBIC - Repels water • HYDROPHILIC - Attracts water • AIR LAYER - Similar to a vapor barrier in a building’s skin • TRICHOMES - The groups of hairs in a “whisk” shape • HAIRS - Small filaments that cover the surface • KINETIC ENERGY - Energy in motion • ELASTICITY - ”stretchiness”, pops back into shape • SURFACE TENSION - Intermolecular attraction of water to itself • TERRESTRIAL - Of, on, or relating to the Earth • EPITICULAR WAX CRYSTALS - Formations of crystaline wax structures to repel water • CONTACT ANGLE - The angle between a solid surface and a tangent of a drop (over ninety degrees is considered “unwettable”) • ADHESION - The tendency of dissimilar particles to stick together
Cerman, Zdenek, et. al. ”Dry in the Water: The Superhydrophobic Water Fern - a Model for Biomimetic Surfaces.” Functional Surfaces in Biology, Springer, Dordrecht, 2009, pp. 107
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Cerman, Zdenek, et. al. ”Dry in the Water: The Superhydrophobic Water Fern - a Model for Biomimetic Surfaces.” Functional Surfaces in Biology, Springer, Dordrecht, 2009, pp. 106
DESIGN STRATEGY
To better protect the interiors of buildings from flooding, both water-repellant and water-attracting coatings can be applied to an irregular surface at teh base of the building. This will allow the water to roll off without permeating the built environment and causing damage.
By keeping the surface irregular and water-repellant, the water will roll away from the building, unable to seep in.
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”By increasing the wetted surface area, the hydrophobility or water repellence is also increased.” Cerman, Zdenek, et. al. ”Dry in the Water: The Superhydrophobic Water Fern - a Model for Biomimetic Surfaces.” Functional Surfaces in Biology, Springer, Dordrecht, 2009, pp. 99
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PLAN VIEW
SECTION VIEW
By slightly raising and inclining the base of the building, then coating an irregular surface with a water-repellant compound, the surface tension of the water will be kept intact, and it will roll the water away.
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EMULATE & DISCOVER
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1. WHAT IS THE ORGANISM OR STRUCTURE YOU ARE FOCUSING ON FOR YOUR FINAL WORK? I will be focusing on the Salvinia Water Fern. Specifically, the plants ability to slough off water from its surface through its use of both hydrophobic and hydrophilic filaments, as well as its use of troughs to direct the water. 2. WHY DID YOU SELECT THIS? HOW DOES IT ADDRESS YOUR PROBLEM? I selected this organism because of its resilience during floods and heavy rains. I want to improve building skin’s resistance to water penetration, and I think the Salvinia Fern will help by showing how its leaves remain untouched by water, regardless of the depth or intensity of flooding. 3. RESTATE AND REFINE THE BIOLOGICAL STRATEGY YOU ARE USING: By emulating the hairs of the Salvinia Water Fern, which are “whisk” shaped and have a hydrophobic body, a protective layer of air is formed. The fern also has an irregular surface, which reduces the contact angle with water droplets, allowing them to slide off easier.
Peaks and valleys (or troughs) reduce the contact angle of water droplets. The droplet’s surface tension causes it to spread further, which reduces the strength of it’s attraction to the surface.
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Additionally, the troughs on the Salvinia Fern widen as they approach the edge of the leaf, directing the water off its surface, rather than allowing it to pool in the middle.
The surface of the fern is covered in microscoping hairs to keep the water off the leaf. The top of the hair is hydrophilic, and the ”stalk” is hydrophobic. The hairs are close enough to use the surface tension of the water to create a protective air layer.
When combined, the hairs keep the water off the surface, and the irregularity of the surface is mirrored in the hair to direct the water off the leaf. The water is never able to touch the leaf’s surface.
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4. REWRITE AND REFINE YOUR DESIGN STRATEGY: By adding a layer that attracts water over a water-repellant layer on the skin of a building, it will be possible to create a protective air space on the exterior of a structure. To direct the water away from penetrations in the skin, small troughs will be added to the surface, which will give better control over the flow.
By applying an irregular, water-repellant coating to the outside of a skin, then adding a layer of waterattracting filaments, a protective layer of air is easier to achieve.
A water repellent chemical can be applied to almost any material. This design would work best with brick or masonry engraved with channels to direct the moisture. A construction fiber (such as jute, flax, hemp, etc.) can then be applied to seperate the water from the skin.
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By adding channels that direct the water away from penetrations in the skin, as well as a lip around the penetration, the skin is further protected from water. 5. REVIEW WITH A CRITICAL EYE: • WOULD THE WALLS OF THE BUILDING HAVE THIS SYSTEM? Yes, step four helped to ensure the walls would be coated with this system to better protect the interior of the building. • WOULD IT ALSO CATCH WATER FOR REUSE? The runoff could be directed into channels that could lead to underground tanks/vessels.
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• CAN REPELLANT AND ATTRACTION BE USED INTERCHANGABLY/ QUICKLY CHANGED? In the current design, the attractant and repellant are used in tandem, but this is a possibility for future refinements.
REFINEMENTS TO THE INITIAL DESIGN 1. LIST THE FEEDBACK THAT WAS INTEGRATED INTO THE REFINED DESIGN AND WHY IT WAS INCLUDED: • This system should be integrated into the whole facade, not just the base • This is important feedback because it will help to achieve the overall goal more effectively. • This system should catch water for reuse •
This is a great idea that would help the building be more sustainable. • The system should be included in the roof as well • This will help keep water from pooling and leaking in the roof. 2. HOW DID THIS INPUT CREATE A NEW OUTPUT FOR YOUR DESIGN? The feedback above helped to fully integrate this idea into a full system for a building’s envelope, rather than a single component that could be added to a building. It also helped improve the expected efficiency of the system, as well as the sustainability of the system.
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3. FURTHER REFINE YOUR STRATEGY FIBER By using a coated mesh fabric and coating it with a starchy, hydrophilic powder, it will attract water and keep it away from the facade. This mesh will be a quicker application than thousands of individual fibers would be.
https://www.tensionstructures.com/portfolio/ - Images https://www.biologyonline.com/dictionary/hydrophilic - Hydrophilic Material Information
SURFACE By coating a rough surface (such as brick or CMU) with a silicon or similarly hydrophobic coating, the water that manages to get through the mesh will not stay on the surface. The Stocolor Lotusan coating is engineered to mimic the lotus leaf, but it is susceptible to debris, pollution, and dilution when there is too much moisture. In conjunction with the screen described above, the coating will be much more durable. https://www.stocorp.com/hydrophobic-stucco/ - Hydrophobic Coating
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4. FURTHER YOUR DESIGN STRATEGY BASED ON THE FEEDBACK AND REFINEMENT:
By combining the mesh (with hydrophilic coating) with the Lotusan coated CMU, the facade will be much more water-repellant. Based on the feedback provided, a water reclamation system was added, which will work in tandem with the water repellant facade. This system emulates the Salvinia Fern by using two layers that work together. The outer layer attracts water, directing it away from the hydrophobic inner layer. This will help keep water from seeping into a building.