The warmest material is aerogel (Chinese: aerogel). Even if the author adds that building materials are not needed, they should be able to be worn on the body and so on. This is true, because aerogel materials have been used in clothing, but the price is very high, 400-550 dollars. (In fact, it is still much cheaper than mink. )
Brands using this material are Champion, Hugo Boss (price 1000 yuan or more), Burton (seemingly discontinued), Russell outdoors and New Rockey Haitao.
A man who climbed Mount Everest in a "super suit"
from
However, the climate in the northeast may not be cold enough to wear clothes made of this material, because it has strong thermal insulation and will have overheating problems.
So I still agree with @BABAB ABABA to buy professional outdoor equipment insulated jackts, which is the most convenient way to experience the power of science and technology.
What is aerogel?
Reachers, here comes the link. Wikipedia-Aerogel
Super thermal insulation performance
This material is ultra-light and is the lightest solid known at present (the picture below shows carbon aerogels).
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Image source: ews.com Wikipedia.
Believe in the power of technology.
Edited on 2014-12-18. The copyright belongs to the author.
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Retired Laogangjing Clothing Dianshang
I don't agree to praise aerogels highly. If you want to learn clothing, I suggest studying textile materials first. Aerogels are just materials, not fibers, not fabrics. Aerogels remain warm because a large amount of air is still under a very small mass. But now there is no aerogel and fibrosis technology. Even if aerogels are fibrotic, it is doubtful whether they can retain static air.
As a contrast with aerogels, down can keep warm and fix the air between fibers; Synthetic thermal cotton can keep warm, and it is a hollow tube made of fiber, and there can be air between the fiber tube and the fiber.
In the application of aerogels, Bosideng Dengfeng series down jackets only use aerogels to protect the pocket interlayer of mobile phones.
Some companies claim that the use of aerogel fiber filler, the essence of which is polyester fiber mixed gas gel material, is still the thermal effect of polyester fiber, just to find a selling point.
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What kind of clothes are the warmest?
At present, the fur of polar bears is the best warm clothing on earth.
Our winter clothes are full of warm cotton, and the thermal reflection technology of down jackets and cotton-padded jackets are all bionic technologies related to polar bear fur.
In extremely cold weather, wind and water are the real enemies, but even in the coldest weather, polar bears can play on icebergs and swim more than 10 km in cold sea water.
Polar bear hair is hollow and transparent capillary.
Polar bears have two layers of hair, the outer layer is oily and waterproof needle-like hair, which can prevent seawater from invading when swimming, and the inner layer is warm fluff. When the polar bear's "white hair" is placed under an electron microscope, it will be found that the polar bear's hair is not white, but hollow and transparent capillaries. The "white" that people see with the naked eye is formed because the inner surface of hair is rough and uneven, which makes the light refracted very disorderly.
There is a lot of still air in the hollow capillary of polar bear, which is the material with the lowest thermal conductivity, so polar bear hair is an excellent warm fiber. Similarly, down keeps warm because a lot of still air is locked between down filaments to keep warm, similar to polar bear hair.
Polar bears have black skin under their "transparent" fur. We can see the original appearance of the skin from the black skin around their noses, paw pads, lips and eyes.
Black skin helps to absorb heat. The researchers found that the polar bear's special transparent capillaries allow high-energy ultraviolet rays in the air to pass through the hair core, reflect to the black skin under the hair, and convert them into heat energy. Blood under the skin transmits heat energy to the whole body.
Polar bear hair can reflect thermal radiation, which is almost invisible in thermal imaging cameras. Only the head, nose and mouth have heat.
Not only that, polar bear hair can also reflect infrared radiation. Polar bears, like people, are warm-blooded animals, emitting heat all the time, that is, thermal radiation. The polar bear's hair is wrapped around the body, which can reflect the thermal radiation of the body and reduce the heat emission, thus ensuring the temperature of the body.
"bionic products of polar bear fur"
Polar bear fur, waterproof and warm, can absorb ultraviolet rays and absorb heat, and can also block body heat dissipation. A series of magical structures have become the warmest clothes in the world, which has also inspired human beings and developed related bionic products.
For example, the structure of polar bear hair, the outer layer is waterproof, and the inner layer is hollow tubular warm cotton. PrimaLoft, 3M Sunsherry, DuPont Thermolite, etc. Are based on this principle.
Dupont Thermolite has developed seven-hole thermal fibers, four-hole fibers and single-hole fibers that imitate polar bear hair.
PrimaLoft thermal cotton has the water repellent effect of polar bear hair and prototype thermal cotton.
The cotton-padded jacket made of warm cotton still has a warm effect of more than 95% in ice water or wet state.
The structure of early spacesuits has several aluminum foil interlayers, which reflect the thermal radiation of the body to keep warm like polar bear hair.
20 19, 10, 15 On June 5th, the National Aeronautics and Space Administration released the next-generation spacesuit with more flexibility and higher security. The left-hand extravehicular spacesuit can work in the temperature range of about 157 degrees Celsius to about 12 1 degrees Celsius.
The outdoor Omi thermal energy reflection technology in Columbia, USA, uses silver polyester fiber yarn to make the warm lining of clothes. With this thin lining, the warm-keeping effect of down jacket can be improved by 20%.
I have always been impressed by the propaganda map of Omni Heat Omi thermal reflection technology at Columbia University.
The bionic technology based on polar bear fur is still under development, which is expected to surpass the warm-keeping effect of polar bear fur.
There are many small holes in the cross section of freeze-spun fiber, which can fix small mass of air.
20 18 the academic weekly "new materials in materials science" published the research results of professor Bai Hao of Zhejiang university, imitating the structure of polar bear hair, and dissolving silk in water to make spinning solution with water content of 95%. After that, the mixture was slowly injected into a cryogenic device with a syringe to form a frozen porous fiber with a diameter of about 200 microns and containing ice crystals. Finally, through freeze-drying, the ice crystals in the fiber sublimate, leaving many orderly layered holes.
"We were surprised to find that the thermal conductivity of this material is lower than that of the original polar bear hair, and it is also warmer," Bai Hao said.
This kind of thermal insulation fiber, like polar bear hair, can reflect the thermal radiation of the body, reduce the heat emission and achieve the effect of "thermal stealth" in front of thermal imaging equipment.
In the future winter, we may bid farewell to heavy coats and put on "sweaters" as thin as cicadas' wings to go out; Soldiers fighting on the battlefield can successfully avoid infrared detection under the protection of "thermal invisibility cloak" ...
Bai Hao has also obtained a patent for this frozen spinning technology, and he hopes to develop this fabric into a commodity. And he is also very optimistic about his achievements in the industrial and military fields. "If you use it to produce military uniforms, you can hide the traces of soldiers."
However, French scientists, who also study freeze spinning technology, believe that Bai Hao's goal may not be achieved in a short time. "With the current technology, the process of producing a fabric is too time-consuming to reach the level of mass production."
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My personal opinion is that the fur coat of polar bear is suitable for human clothes at this stage. Close to the polar bear fur coat are seals, walruses and other animals living in the polar regions. Eskimos sew fur coats with seal skins.
Clothing has developed rapidly, but the textile industry behind it has not progressed rapidly. In addition to the research and development of new products, there are also low-cost mass production and commercialization, and every step is too difficult. The so-called black technology warm clothes appeared one after another, but they all died. Either it's nonsense or it can't solve the cost of mass production.
nude
Inflatable cotton-padded jacket, like Nudown, was born in 20 14, and there were high light moments in China. The outer fabric is made of Polartec Neoshell, and the outer area of the big body is filled with lint, and the big body is inflated to keep warm. In cold weather, more air expands. In order to solve the moisture permeability, sweating parts such as underarms are zipped. This seemingly reliable solution is now half dead.
Real new black technology products, the initial mass production are all military applications. In China, if there is a company that can mass-produce and sell aerogels, frozen spinning fibers or similar new products, it must be Jihua.
reference data
Pictures of polar bears and polar bear fur, transferred from National Geographic.
Weaving polar bear "sweater" with porous bionic fiber, Science and Technology Daily
Bai Hao, 2065438-2005-09, researcher and doctoral supervisor, School of Chemical Engineering and Bioengineering, Zhejiang University. Professor Bai Hao was born in Chongqing, 1983, and graduated in 2006, the same year as me ... sincerely convinced.
Edited on 20 19- 12-23. The copyright belongs to the author.
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Gao Tianqi
Professional meat beating for more than a week. Three generations of poor victims of photography.
If the level of science and technology allows, it is warmest to wear a still air coat (thanks to DerCampus).
But technology doesn't allow it.
So, what material can keep the air best and what material can keep the warmth best?
What material can hold the most air?
Go down.
The human body is a constant temperature body, which is itself a heat source and constantly generates heat. This heat needs to be released. If the heat is released little or slowly, the human body will feel hot, for example, in summer. If the heat is released more or faster, the human body will feel cold, such as in winter.
When the human body feels cold, it will consciously add clothes. Adding clothes is not a human instinct, but a life experience. Why do you add clothes to keep warm? The so-called warmth is actually to prevent heat loss.
There are three main forms of heat dissipation: heat conduction, heat convection and thermal radiation (thermal radiation means that each heating body radiates electromagnetic waves around, which is mainly reflected in the microscopic field, so I won't go into details this time. * In the 1980s, the United States developed a new material for astronauts-space cotton, that is, aluminum foil was added to the fiber, so that the heat radiated by human body was reflected back to human body by aluminum foil, and at the same time, it accelerated the thermal insulation of human cells).
If you wear clothes made of iron sheet, you will still feel cold, because iron sheet is a good heat conductor with high thermal conductivity. The thermal conductivity of common clothing materials is low, among which the thermal conductivity of down is the lowest (5.930), the thermal conductivity of wool is about 15% higher than that of down (6.986), and that of cotton is about 39% higher than that of down (9.7 17).
In addition, there is another index that can measure the thermal conductivity of fiber, and that is the heat preservation rate. The higher the value, the better the insulation effect. The warmth retention rate of down is the highest among common fibers (8 1.3%), the warmth retention rate of wool is about 6.5% lower than that of down (74.8 1%), and that of cotton is about 63% lower than that of down (kloc-0/8%).
Combining thermal conductivity and thermal insulation rate, we can draw the conclusion that "the thermal insulation effect of down is the best under the premise of the same thickness".
However, although it is numerically superior, if the thickness of materials such as wool or cotton is increased, its warmth retention effect can surpass that of down. This is in line with human life experience: the thicker clothes you wear, the warmer you stay.
Humans have another life experience: the thicker clothes they wear, the more clumsy they look. Moreover, no matter how good the thermal insulation effect is, the fiber still cannot reach the thermal conductivity of 0 and the thermal insulation rate of 100%. The only thing that can achieve this "absolute warmth" is air. For example, "double glass" is often installed on the windows at home, and there is a layer of air between the two layers of glass. You usually feel warmer in a room with double glass.
In that case, we should stand naked in the air, don't we feel cold?
Because the second form of heat loss is "thermal convection". When the air near your body absorbs the heat emitted by your body, the density will become lighter. According to the principle of nature, light-density air will automatically rise, and the vacated place will be automatically supplemented by cold air nearby. So the air around the human body is always cold, so it will feel cold.
As long as it is the gravity environment of the earth, air convection is inevitable in an open space. If the convection of air stops in a weightless environment, even if the temperature is 0 degrees, people will not feel cold naked, because the air close to their bodies is hot. It is equivalent to a layer of hot air attached to the human body. But the premise is that people can't move, because this layer of hot air only stays in that place and won't move with the human body.
So how do you put on a "space suit" under the gravity of the earth? It is obviously unrealistic to wear a layer of insulating glass, so wear a plastic film filled with air. This layer of air is static and sealed. No matter how the human body moves, it will move with it. Figuratively speaking, it's like breathing in a balloon with only your nose exposed. First of all, I suddenly became an anime character. Needless to say, the human body emits moisture as well as heat. In a closed environment, moisture can't be discharged, and people will feel very uncomfortable. After all, the skin also needs air exchange.
In fact, when it comes to this point, we can actually come to a conclusion: the fiber itself can't keep warm, but the air that can keep warm is entrained in the fiber, which shows the effect of keeping warm. The amount of air entrained in the fiber directly affects the thermal insulation effect of the fiber.
Then, why are they all fibers? Under the same thickness, why does down have the best thermal insulation effect?
This can be analyzed from the molecular structure of down:
1. Macromolecules are curled when they form fluff fibers, thus forming a large number of cavities. This leads to each feather silk being hollow and full of air, which is the best heat insulation material.
2. Each velvet flower contains dozens of filaments with the same structure, and there is a certain repulsion between each filament, so that the spacing between each filament can be kept to the maximum, and theoretically more air can exist.
3. There are many secondary filaments in each filament. When many down feathers are mixed together, the secondary filaments interweave and overlap with each other, forming multiple barriers, preventing the free flow of air and increasing the difficulty of air convection.
Down fiber is radial, so it stores more gas than linear fiber such as wool and cotton, so it has the best warmth retention effect.
Of course, as mentioned above, wool, cotton and other fibers, if the thickness is increased, their warmth retention effect can surpass that of down. But you will feel bloated.
Therefore, if the outdoor temperature is low, people want to keep the same body surface temperature by wearing clothes, whether it is down, wool or cotton, it can meet the requirements.
But the thickness of down jacket is much lower than that of wool and cotton-padded jacket.
With regard to the bulkiness of various fibers, it is proved that the larger the volume of aggregate with air, the greater the air volume that can be effectively controlled and the stronger the warmth retention. The smaller its mass, the lighter it proves. The experimental results show that the geometric volume of down fiber is the largest (382.56 cubic centimeters), which is more than three times that of wool fiber (10 1.24 cubic centimeters) and five times that of cotton fiber (76.92 cubic centimeters). At the same time, the minimum weight of down fiber (1. 14g) is about 86% of wool fiber (1.32g) and 74% of cotton fiber (1.54).
Practice has proved that down fiber can effectively control the maximum air volume and the minimum air volume.
From a dimensional point of view, you can also look at it.
According to the theory of Euclidean geometry, the dimension of geometry is 1, 2 or 3, all of which are integer values. But the fibers in nature are not all integer values after long-term evolution. Through computer simulation, the size of down fiber is about 1.66.
We know that one-dimensional geometry only has the concept of length, and two-dimensional geometry has the concept of surface area. Explaining it in easy-to-understand terms can be understood as follows: a geometric body between one and two dimensions can be understood as having a very small two-dimensional feature, that is, surface area, as long as the dimension is less than two dimensions, no matter how far it is from two in value; But the closer the dimension value is to 2, the greater the one-dimensional characteristic, that is, the length. Therefore, the size of down fiber is 1.66, which can be understood as a relatively small surface area but a relatively long length. It can be compared that the size values of wool and cotton fiber are close to 1.0. In other words, under the same surface area, the length of down fiber is longer.
The size of down fiber is between one and two dimensions. Because all down fibers are radially distributed in space, down fibers are between two-dimensional and three-dimensional, which can be understood as relatively small volume but relatively large surface area. In contrast, wool and cotton fibers do not have radial spatial distribution. So the air that velvet flowers can lock is the biggest.
The same down jacket will have different warm-keeping effects, which are mainly reflected in three aspects: cashmere filling, cashmere content and bulkiness.
First look at the filling quantity:
1. With the same volume of space, the more down is filled, the thicker the down is.
2. When the filling amount reaches a certain mass, the upward trend of down thickness slows down.
3. There is a value, when the filling amount reaches this value, the thickness of down reaches the highest point (saturation).
4. The higher the cashmere content, the lower the saturation value.
The thickness reaches the highest point, indicating that the down contains the most gas.
When the filling amount reaches saturation, the thermal insulation rate is the highest and the thermal conductivity is the lowest. If we continue to add down, the heat preservation rate of down products will decrease slightly.
Secondly, look at the cashmere content:
1. When the wool content is constant, the higher the wool content, the higher the heat preservation rate and the lowest the heat transfer coefficient.
2. When the wool content reaches a certain value, the heat preservation rate and heat transfer coefficient tend to be stable.
3. When the filling amount is close to saturation, the down content has little effect on the warm keeping effect of down products.
Finally, look at the volume:
1. The higher the fluffy degree, the better the warm-keeping effect of duvets.
2. The amount of cashmere directly affects the bulkiness.
3. Experiments show that when the down content of duck down is high, the fluffy degree will increase by 2.8 for every percentage point increase of down content.
4. Fluffy is also related to the size of velvet flowers. The bigger the velvet flower, the higher the fluffy degree.
The size of the velvet flower depends on the number of days the duck grows. The shorter the growth time of ducks, the smaller the volume of velvet flowers and the smaller the output of velvet flowers (but the edible value is greater); On the contrary, the longer the growth cycle of ducks, the larger the volume of velvet flowers and the greater the output of velvet flowers. (But the smaller the edible value). Generally speaking, ducks with a long growth cycle will change their cashmere every spring after they become adults, and the fully mature cashmere will naturally fall off. At this time, cashmere has the largest and highest maturity, but the labor cost is higher.