Challenge to Biology
Tica Lubin
MASD - Biomimetic Design - SD-6610-21-F21 - C2B spiral -5.2
The Biomimicry Design Sprial walks designers through a nature-inspired process starting with identifying functions and conditions and working through translate, discover, abstract, emulate and evaluate. Often times the spiral is repeated several times leading to new design discoveries. The final design ideas are evaluated against the Living Principles (Biomimicry Insitute)
Design Goal: Running through various elevations
To achieve this goal I looked for models that would work to absorb sweat, stay dry, be lightweight, and provide warmth. When someone runs uphill they will most likely begin to get hot and sweat a bit and then need to take off the jacket or stop and rest and want to leave it on for warmth but not be soaking wet, have it dry and then put it on for warmth on the way down. What models in nature can contribute to these goals, are there organisms that both absorb water and heat?
Spiral 1
Discover: Absorb water
Sand Grouse: The outer fifth of the male sandgrouse’s abdominal feathers resembles the waterproof feathers of other birds: loosely webbed hairlike structures (called “barbules”) extend from the branches (called “barbs”) that protrude from the main feather spine. However, the inner four-fifths of sandgrouse feathers instead have specialized flattened, ribbon-like barbules that coil about 3.5 times along each barb, forming an overlapping helical pattern. When dry, this structure appears as a springy, strong, and flat web. When wetted, the barbules uncoil rapidly, allowing minuscule filaments on the tips of the barbules to stand up. This structural change substantially increases the surface area of the feather, which then draws in water by capillary action. Male sandgrouse can carry an estimated 22 mL of water in their feathers—approximately 8 grams of water per gram of dry feather weight (this is at least twice as absorbent as a typical synthetic kitchen sponge!).
On a molecular scale, sandgrouse feathers are made primarily of the protein β-keratin. The arrangement of β-keratin molecules becomes less ordered (i.e. less crystalline) when wet, which may be essential to understanding the feathers’ absorbency. When a sandgrouse wets his belly feathers, water molecules bind with the charged (polar) parts of the barbules’ proteins, which then expand to accommodate the water. This process is what causes the β-keratin to lose some of its crystalline structure: molecules become more separated and randomly arranged. Notably, this mechanism is entirely reversible. Once dry, the feather barbules return to their coiled state, and the β-keratin recrystallizes. (Ask Nature)
So then the question would be how to move that water out across the fabric to the outside where it would dry from wind and the sun. To this we can look to Aquaporin molecules form a channel that allows water to move across cell membranes. How does a cell keep the amount of water just right? The answer lies in hourglass-shaped molecules with a tunnel down the middle that are very, very picky about what they let through. One type of channel, called aquaporins, selectively let water molecules move across the cell membrane. These channels are so important that they are found in organisms belonging to all kingdoms of life. The center of the aquaporin channel carries a positive charge, which repels other positively charged molecules and prevents them from passing through. Thus, only small, uncharged molecules such as water are able to pass through the channel. Increasing efficiency, aquaporin molecules tend to appear in groups of four arranged together, creating a fifth pore in the middle that also moves water across the membrane. (Ask Nature)
Abstract
Design principles that can be abstracted from these organisms are a way to latch on to water molecules and a way to move water molecules across a barrier.
Brainstorm
In what ways can fabrics be combined to both pull water from someone who is sweating but then also take that water and move it away from the person so that they stay dry and the fabric does not become heavy and wet?
Emulate
Develop a fabric that is two layers = one that is textured to mimic the fathers of the Sand Grouse paired with one whose fabric is structured in a way to create minuscule channels to pull water through to the outside.
Evaluate
Using benign chemistry, fostering cooperative relationships, free energy, locally attuned
Spiral 2
Discover: Deter water - can the outer layer shed the water pulled from inside as well as stay dry?
Zoom into a cicada’s wing with a powerful microscope and you will see that the seemingly flat wing is anything but. Poking up from the wing’s surface are tiny pillars arrayed in row upon row with the precision of a marching band.
Each “nanopillar” measures only up to a few hundred nanometers high. That’s about 4,000 times thinner than a strand of human hair.
A drop of water, in contrast, is a thousand times larger. So a drop that lands on the bumpy cicada wing has no flat surface to stick to. Even tiny droplets in fog and mist can’t get traction.
The wings are also coated with a variety of naturally water-repellent waxy substances. Unlike water, which has slight positive and negative charges at different ends of each molecule, these compounds are nonpolar. That means the water molecules are electrically attracted to one another, but not to the waxes. These combined structural and chemical deterrents induce water to slide off when the wings tilt a little, often flushing away any dirt particles in the process. Like water drops, potentially disease-causing bacteria are also repelled and shed by the waxy nanopillar structure, staving off infection. (Ask Nature)
Abstract
Take the pillared structure of the cicada wing and create a fabric that has a similar nano structure to it.
Brainstorm
Could an outer layer of the jacket also mimic this pillared structure to expell water and dirt?
Emulate
Make a jacket with this as the outer layer to stay dry as well as to shed water that comes from the inside versus trap it.
Evaluate
Using benign chemistry, fostering cooperative relationships, free energy, locally attuned
Spiral 3
Discover: Stay warm
In the animal kingdom, marsupials have several characteristics that set them apart. But even among marsupials, the numbat stands alone.
Unlike most marsupials, which generally eat plants, fruits, and sometimes insects, numbats are entirely carnivorous. More particularly, they are termitivorous. They eat nothing but termites, which come out by day.
Given their singular schedule and diet, numbats have had to adapt to maintain ideal body temperatures. A major way they do that is with another feature that sets them apart. Unlike most marsupials, which have thick fur coats, numbats have sparse pelts—which counterintuitively help regulate their body temperatures and keep them warm.
Since numbats don’t get enough fuel from termites to maintain body heat, they rely on absorbing heat from the sun. Their pelts have shorter hairs and fewer hairs per square inch, compared with other marsupials and diurnal mammals. So their sparse coats are not made to insulate against the cold, but rather to expose more skin area to the sun, maximizing the amount of solar radiation they absorb.
They also make their pelt hairs stand up straight. The scientific term for this is piloerection. It happens to people when they get goosebumps.
Piloerection traps layers of motionless body-heated air close to the skin surface. These layers block heat loss from the body, creating a blanket that helps insulate numbats from cold. As temperatures drop or cold winds pick up, numbats effectively reduce heat loss by erecting their pelts. Altogether, numbat pelts strike a balance between regulating how much heat gets in and how much is allowed out. (Ask Nature)
“At the other extreme are butterflies like Ornithoptera priamus–‘ultrablack,’ [Peter] Vukusic calls it. Again, structure is key. Its honeycombed wing scales absorb more light than would a smooth surface, so the black pigment looks blacker still. The hue helps regulate body heat and makes other wing colors stand out in mating displays.”(Ask Nature)
Abstract
Use the structure of hairs standing straight up to capture heat combined with sections of black honeycomb to absorb light and heat.
Brainstorm
Could an outer layer of the jacket have a nanopillared fabric and black sections to help to absorb heat for when a person reaches higher elevations or sudden changes in temperature occur as well as expell accessive heat generated from internally.
Emulate
Make a jacket with this as the outer layer to stay dry as well as to shed water that comes from the inside versus trap it.
Evaluate
Using benign chemistry, fostering cooperative relationships, free energy, locally attuned
Final Design
This jacket would have an inner layer with a nano structure to mimic the sand grouse feathers to capture sweat. This would be paired with a layer of hourglass-shaped structures creating an aquaporin channel. Water would be pulled out to the outer structure that would be a combined material of honeycomb to gather heat that would also cause evaporation as well as a pillared structure to insulate heat. The materials would be made from a fine thread that is strong like a spider web that also repels water and is made of hydrogel, which is 98 percent water and 2 percent silica and cellulose, the latter two held together by cucurbiturils, molecules that serve as “handcuffs.”
The fibers are extremely strong – though not quite as strong as the strongest spider silks – and, significantly, they can be made at room temperature without chemical solvents. The artificial spider silk is also completely biodegradable. And since it’s made from common, easily accessible materials – mainly water, silica and cellulose – it has the potential to be affordable.(Smithsonian)