Smart knitted products are developed through a combination of different raw materials, finishing technology and electronic information technology. According to their ability to perceive and respond to external stimuli, they can be mainly divided into three types: passive smart knitted products, active smart knitted products type knitted products and advanced smart knitted products. In the design process of smart knitted products, the development is guided by the application requirements of the product. The applications cover various fields such as human protection, medical testing, smart home, and special military.
Passive intelligent knitted products
Passive intelligent knitted products can sense external stimuli, but do not have the ability to automatically control and respond. Passive smart textiles usually use optical fibers or conductive fibers combined with sensors to complete one-way transmission of stimulation signals such as displacement, mass, temperature, humidity, pressure, current, and magnetic field.
1 Fiber knitted sensor
Fiber knitted sensor uses fiber grating braiding Or it can be lined into knitted fabrics to form small light-emitting diodes, which can detect changes in light intensity or amplitude through fiber gratings, and sense displacement and pressure based on the movement of textiles and changes in light. Since optical fibers have poor ductility and are not easy to form knitted loops, developers usually use optical fibers as inlaid yarns to form a three-layer structure on the knitted fabric during the knitting process. The optical fibers serve as the middle layer and are fixed by both sides of the fabric. .
2 Conductive knitted sensors
In the research and development process of smart textiles, conductive fibers are one of the most commonly used materials to weave flexible knitted sensors. . The conductive fiber can be a chemical fiber filament whose surface is plated with conductive metal/conductive polymer, or metal filament such as silver wire or copper wire, or carbon fiber that meets the requirements of knitting yarn. By weaving different knitted tissue structures, two different types of flexible strain sensors, capacitive or resistive, can be prepared to measure pressure, temperature or humidity. The on-off of the sensing circuit can also be used to control the switch of the circuit to achieve counting. the goal of.
Active intelligent knitted products
Active intelligent knitted products can sense external stimuli and have the ability to automatically control and respond.
1 Shape memory knitted products
Shape memory materials refer to A material with a specific initial shape that is deformed or set and can be restored to its original shape when external stimulation such as heating is applied. The principle is that the material is in a stable state at two or more temperatures. When the conversion temperature reaches a certain stable state, the material deforms to reach that state. Currently, shape memory alloy wires are commonly woven into shape memory knitted products and used as medical reinforcement fabrics. In terms of clinical treatment of coronary heart disease, inhibition of tumor growth, and smooth metabolism, the fusion of weft-knitted coil structure and shape memory materials can flexibly bind human tissues and organs, and flexibly support blood vessels. In the production of knitted clothing, the shape-retaining properties of shape memory fibers can be fully utilized to form linings in warp-knitted polycomb fabrics and warp-knitted spacer fabrics for the production of shoe upper materials, bags, hat brims, underwear and other smart products.
2 Photothermotropic knitted products
Photothermotropic knitted products refer to reversible changes in the color and mechanical properties of knitted fabrics under the action of light or heat. Color-changing materials are added to the spinning solution and spun by dry, wet or melt methods to produce fibers with light/temperature-sensitive discoloration properties. For example, PINTO uses melt spinning to produce photochromic knitted products. . Knitted products woven using photochromic fibers can change color under the action of visible light or ultraviolet light, and return to their original color when the light effect is lost. This provides new ideas for aesthetic innovation and decorative effects of fabrics, and is used in military and special applications. It also has outstanding advantages in the production of protective products.
3 Intelligent temperature-regulating knitted products
Intelligent temperature-regulating knitted products are knitted using phase change fibers. Phase change fibers spun from a spinning solution wrapped with phase change microcapsules. When the external environmental temperature changes, the phase change material can realize the temperature regulation and control function by performing a reversible transformation between the liquid phase and the solid phase. Therefore, It is called heat storage and temperature regulating fiber or “air conditioning” fiber.
Advanced intelligent knitted products
Advanced intelligent knitted products refer to products that canKnitted fabrics that adapt to the environment can not only sense external stimuli, but also show dynamic adjustment adaptability according to external stimuli. Advanced intelligent knitted products are knitted products developed based on electronic technology and applying high-tech means such as sensing, communication, and artificial intelligence to textile technology. Smart textiles that have been developed at home and abroad are embedded with flexible electronic components inside textiles, integrating sensors, flexible textile switches, flexible electronic circuit boards, conductive yarns and textiles.
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