Looking ahead: what are the functions of smart materials in the future?

The development and large-scale application of smart materials will lead to a major revolution in the development of materials science.
Generally speaking, the application of smart materials in the electronics industry has seven functions, namely sensing function, feedback function, information recognition and accumulation function, response function, self-diagnosis ability, self-repair ability and self-adaptive ability.
The idea of smart materials comes from bionics (bionics is to imitate some unique functions of creatures in nature to make tools used by humans, such as imitating dragonflies to make airplanes, etc.). Its goal is to develop a material that makes it similar "Living" materials for various biological functions.
Therefore, smart materials must have the three basic elements of perception, drive and control.
However, the existing materials are generally relatively single and difficult to meet the requirements of smart materials. Therefore, smart materials are generally composed of two or more materials to form a smart material system.
This makes the design, manufacturing, processing and performance and structural characteristics of smart materials involve the most cutting-edge fields of materials science, making smart materials represent the most active aspect and the most advanced development direction of materials science.
In the field of architecture, scientists are focusing on researching and developing materials that enable bridges, tall buildings, and underground pipelines to diagnose their "health" by themselves, and that smart materials can "cure diseases" on their own.
British scientists have developed two types of "self-healing" fibers.
These two kinds of fibers can respectively sense cracks in concrete and corrosion of steel bars, and can automatically bond concrete cracks or prevent corrosion of steel bars.
The fiber for bonding cracks is a porous hollow fiber made of glass fiber and polypropylene. After it is mixed into concrete, it will be torn when the concrete is excessively flexed, thereby releasing some chemical substances for filling and Glue cracks in concrete.
Anti-corrosion fiber is wrapped around the steel bar.
When the acidity around the steel bar reaches a certain value, the coating of the fiber will dissolve, and substances that can prevent the steel in the concrete from being corroded are released from the fiber.
In aircraft manufacturing, scientists are developing smart materials with the following functions: When the aircraft encounters eddy currents or violent headwinds in flight, the smart materials in the wings can quickly deform and drive the wings to change shape, thereby eliminating eddy currents or violent headwinds. The influence of the headwind keeps the plane flying smoothly.
Aircraft self-diagnostic monitoring system that can perform damage assessment and life prediction.
The system can judge sudden structural damage and cumulative damage on its own, and predict the life of the aircraft structure based on flight experience and damage data, thereby greatly reducing the number of grounded inspections and routine maintenance costs while ensuring safety, so that commercial aircraft can obtain considerable Economic benefits.
In addition, some people have imagined using smart materials to make paint and apply it on the fuselage and wings. When stress occurs in the fuselage or wings, the paint will change color as a warning.
In the medical field, smart materials and structures can be used to make prostheses that do not require motor control and have a tactile response.
These prostheses can imitate the smooth movement of human muscles, using their controllable shape-restoring force to dexterously grasp fragile objects, such as paper cups filled with water.
The automatic drug delivery system is also a territory where smart materials show their talents.
Japan introduced a polymer that expands and contracts according to the concentration of glucose in the blood.
When the glucose concentration is low, the polymer strips will shrink into small balls, and when the glucose concentration is high, the small balls will stretch into ribbons.
"With this feature, this polymer can be made into artificial pancreatic cells.
Insulin pellets encapsulated with this polymer are injected into the blood of diabetic patients, and the pellets can simulate the work of pancreatic cells in the human body.
When the blood glucose concentration is high, the pellet releases insulin, and when the blood glucose concentration is low, the insulin is sealed.
In this way, the patient's blood glucose concentration will always remain at a normal level.
In the military, smart skins that can detect lasers, nuclear radiation and other sensors are implanted in the skins of aerospace vehicles, which can be used to monitor and warn of enemy threats.
The United States is studying the implantation of nuclear explosion fiber sensors and X-ray fiber detectors in composite skins for future ballistic missile surveillance and early warning satellites.
This kind of smart skin will be installed on the surface of the space-based defense system platform to conduct real-time monitoring and early warning of enemy threats and improve the weapon platform’s ability to resist damage.
Smart materials can also reduce noise in military systems.
The U.S. military invented a smart material that can be coated on submarines, which can reduce submarine noise by 60 decibels and shorten the time for submarines to detect targets by 100 times.
In addition to the above aspects, another important development sign of smart materials is shape memory alloy, or memory alloy.
This alloy can remember its shape after being formed at a certain temperature.
When the temperature drops below a certain value (phase transition temperature), its shape will change;
When the temperature of the shape memory alloy rises above the phase transition temperature, it will automatically return to its original shape.
At present, the basic research and application research of shape memory alloy are relatively mature.
Some countries have made self-deploying antennas for satellites with memory alloys.
After being welded into a certain shape at a slightly higher temperature, it is folded at room temperature and mounted on the satellite for launch.
After the satellite is in the sky, the temperature will rise due to strong sunlight, and the antenna will automatically unfold.
In addition, some people have made automatic window shutters with memory alloy.
When the temperature rises to a certain level, the window automatically opens, and when the temperature drops, it automatically closes.
The bra that uses memory alloy as the support frame is also very distinctive. The bra can be rubbed and washed in water at will, but when it is worn on the body, it will automatically maintain its own shape and can change within a certain range according to the change of the wearer's body shape.