Adding a layer of self-refrigeration device to the hydrogel can make ice boards and ice walls.
The water does not drip when heated, and can be used to make beautiful reliefs - the only technical solution in the world that can preserve reliefs on ice for a long time.
On the ice board on display in the China Science and Technology Museum, there are carved "city towers" and "snowflakes".
Although many people touched it, the shape of the pattern remained clear.
The Beijing 2022 Winter Olympics have opened, and the popularity of ice and snow sports is also continuing to heat up.
The vision of "300 million people on the ice and snow" proposed by my country at the time has become a reality.
To promote ice and snow sports, there must be ice.
However, the ice and snow in the natural state will melt after heating up, and the water will be dripping, which is annoying.
To build an ice rink manually, it is necessary to build a drainage system, a gravel layer foundation, a heating cement layer, etc. The process is complicated, the mobility is poor, and the cost is high.
The team of Zhang Kai, a professor at the School of Astronautics of Beijing Institute of Technology, developed a new material - gel ice and snow.
Its biggest feature is that it "never melts".
Using a polymer network to lock the hydrogel, ice and snow will not heat up
Recently, at the China Science and Technology Museum, the gel ice and snow ice board prepared by Zhang Kai's team was unveiled at the "Science and Technology Winter Olympics" theme exhibition.
The booth was not big, but it attracted a lot of passers-by.
Out of curiosity, everyone reached out to touch it.
The children liked it very much. They jumped up half body and shouted, "It's cold, it's cold, and it's slippery! It's ice!"
More than 90% of the gel ice and snow is water, so it has almost the same visual and tactile feel as natural ice and snow.
In fact, gel ice and snow at room temperature is a hydrogel material.
It feels similar in texture to jelly, but with better mechanics.
When you poke it with your hand, you can see a small dent in the surface, and it springs back immediately.
You can press it, you can pull it, and you can roll it up—like rolling a blanket.
The secret of non-melting is hidden in a hydrophilic polymer network.
The design and preparation of this kind of network are very particular.
It is formed by the polymerization of a variety of materials through chemical means. According to different needs, the materials, shapes and cross-linking methods of the polymer network are also different.
When there is no polymer network, the ice crystals will melt into water after heating up; but after adding the polymer network, the melted water is also locked in the grid and cannot escape.
That way, even when heated, the hydrogel retains its shape—it's somewhere between a liquid and a solid.
In fact, the masks and antipyretic patches that we are familiar with are all hydrogels.
When making gel ice and snow, Zhang Kai's team deliberately chose biocompatible materials, which are non-toxic and harmless, natural and environmentally friendly, and people can also have intimate contact with it.
Adding a layer of self-refrigeration device to the hydrogel can make ice boards and ice walls.
The water does not drip when heated, and can be used to make beautiful reliefs - the only technical solution in the world that can preserve reliefs on ice for a long time.
On the ice board on display in the China Science and Technology Museum, there are carved "city towers" and "snowflakes".
Although many people touched it, the shape of the pattern remained clear.
There are a variety of interesting applications to help more people feel the charm of ice and snow
For small "ice and snow carnivals" in the city, the gel ice and snow is also easy to carry and install.
At room temperature, you can roll it up, and at the destination, put a layer of ice on it, and add a refrigeration unit, it can be transformed into a small ice rink that doesn't melt.
Gel ice and snow can provide a real ice and snow experience that artificial ice cannot match.
Moreover, the raw materials are cheap, the preparation method is simple, no expensive large-scale instruments are needed, and the maintenance is easy during use, and the cost can be greatly reduced compared with the artificial ice making technology.
There are many more interesting applications.
For example, make ice and snow themed cafes.
The gel ice cups and ice bowls prepared from gel ice and snow do not melt, lose their shape, have strong toughness, are not easily broken, and can be reused.
Think about it, the customer takes a beautiful ice cup and pours hot coffee. The coffee cools down, and the ice cup becomes soft and glutinous due to the heating. It has the potential to become a check-in point for Internet celebrities.
It is also possible to continue to "refinish" the material.
Gel ice and snow can introduce elements with characteristics of light, electricity, magnetism, etc. to realize functional design, such as making it shine, or make it into a refrigerator magnet.
The gel ice and snow team led by Professor Zhang Kai belongs to the wave mechanics team of the Department of Mechanics, School of Aeronautics and Astronautics, Beijing Institute of Technology.
A few years ago, they began to study hydrogels, the main direction is to combine it with acoustics, and develop advanced acoustic materials for marine equipment and medicine.
For example, the coupling agent applied to human skin over time is also a polymer hydrogel.
The new hydrogel developed by the team can make the patient experience better and the B-ultrasound imaging clearer.
"Hydrogel is a promising material, which can be used in many fields in the future," Zhang Kai said.
However, the combination of hydrogel and ice and snow is the first in the world.
Zhang Kai still remembers that more than four years ago, he received an email from the school, encouraging teachers to actively use their research advantages to serve the Beijing Winter Olympics.
Zhang Kai felt that as a scientific research team of Beijing Institute of Technology, a university with a glorious tradition of serving the country with science and technology, it should help promote ice and snow culture.
In 2008, Zhang Kai watched the 110-meter hurdles competition at the Beijing Olympics, and the atmosphere of the Olympics left a deep impression on him.
"I just wanted to find a way to let more people get in touch with ice and snow, fall in love with ice and snow, and feel the culture of ice and snow."
The team expects that this kind of unmelting ice and snow can bring the charm of ice and snow to more people.
Our reporter Zhang Gailun