The Gorgeous Transformation Of A Piece Of Wool

With the support of the National Natural Science Foundation of China, the research team led by Tang Fangqiong, a researcher in the Laboratory of Controllable Preparation and Application of Nanomaterials at the Institute of Physical and Chemical Technology, Chinese Academy of Sciences, and the team led by Li Yi, a professor in the Department of Textiles and Garments of Hong Kong Polytechnic University, have found a unique nano finishing technology and successfully developed a "moisture absorption and quick drying" with washability Type B wool fabric.

This research achievement has been published in Chemistry&Sustainability, Energy&Materials (ChemSusChem for short), the sister journal of Applied Chemistry of the German Chemical Society. And applied for an international invention patent.

Iron Duner went back to the village from the city and said that there was a machine in the city. When he went in from one end, the pig became ham sausage, and when he went in from the other end, the ham sausage became pig.

This is a part of the crosstalk skit "In front of the Elevator Door".

It also sounds unbelievable that there is another machine: the whole piece of wool will "walk" once from the machine, and the wool will be "nano modified" in the machine, which has many superior properties such as moisture absorption, quick drying, easy perspiration, etc.

The former is just a cross talk burden, while the latter, with the efforts of scientists, is closer to reality step by step.

Technical Challenges of Big Textile Countries

Although China is a big textile country, the domestic textile industry still needs to make continuous efforts in the design and processing technology of new fabrics.

Taking sportswear as an example, according to the data of China Clothing Network, the Chinese sportswear market is growing fastest, and the sales of sports brands in shopping malls are the best in recent years. Ordinary sports brands in the market can easily achieve tens of millions of sales every year. But we are familiar with big brands still rely on imported fabrics to attract customers.

There is a microclimate environment between human skin and clothes. For sportswear, how to reduce the moisture content of this microclimate environment as much as possible, so that sweat on the surface of the human body can quickly diffuse through the clothes and evaporate into the air instead of staying on the skin, and keep the clothes dry and comfortable has always been the goal of people's efforts.

At present, most sports brands on the market use water repellent chemical fibers, especially polyester, polypropylene, etc. The reason why such chemical fiber fabrics can absorb moisture and sweat is that after absorbing sweat, the sweat can diffuse quickly and evaporate quickly on the other side of the fabric.

Among natural fibers, cotton and wool feel comfortable, green and healthy. Especially wool fiber, because of its light weight, soft, warm and other good qualities, has become an ideal clothing material.

Although the moisture absorption performance of cotton fiber is very good, its moisture release rate is very slow, and the diffusion rate of sweat is also slow, making sweat easy to concentrate. Once a person sweats a lot, the cotton fiber feels wet seriously after sweat absorption, and it is uncomfortable to stick on the body. The scale layer structure on the surface of the wool fiber makes the wool fabric naturally hydrophobic, hinders the water absorption ability of the wool fabric, resulting in low moisture absorption and sweating rate, which makes people feel stuffy and uncomfortable after a lot of exercise.

"Therefore, the research and development of 'moisture absorption and quick drying' wool fabrics has always been a hot research topic in this field," said Tang Fangqiong, a researcher in the controllable preparation and application room of nanomaterials at the Institute of Physical and Chemical Technology, Chinese Academy of Sciences.

Functionality and Comfort Proposition

"People's demands on the functionality and comfort of clothes will become higher and higher. In addition, comfort will gradually become the first factor to consider when people buy clothes," Tang Fangqiong said.

With the improvement of living standards, a series of new fabrics came into being. The success of DuPont's high elastic Lycra fiber, waterproof and breathable fabric EXOTHERM functional fabric shows the great power of functional fabrics in increasing product value and meeting consumer demand.

The rise of nanotechnology has also had a profound impact on the reform of the textile field. In recent years, functional nano textile fabrics, such as antibacterial, deodorant, UV resistant and self-cleaning fabrics, have attracted extensive attention. In addition to novel functionality, it is also of great significance to use nanotechnology to develop "moisture absorption and quick drying" fabrics and improve the wearing comfort of fabrics.

Last year, Tang Fangqiong's team and the team led by Li Yi, professor of the Department of Textiles and Garments of Hong Kong Polytechnic University, developed a unique nano finishing technology and successfully developed a washable "moisture absorption and quick drying" wool fabric. The team once coated the surface of wool fiber with a nano thin layer composed of spherical silica, constructed a wool fabric with super hydrophilicity, and discussed the mechanism of nano technology modifying the hydrophilicity of wool fiber.

However, nano functional fabrics still face a major problem in practical application, that is, the new functions of fabrics given by nano technology cannot be maintained for a long time, such as the washability is not enough. After washing, especially the washing method commonly used in people's daily life, its special functions will partially or completely disappear.

New characteristics appear on wool

"Previously Nanofunction The method of fabric preparation is to make nano materials into auxiliaries, and then apply them on the fabric. Nanoparticles are adsorbed on the fabric by electrostatic action, which is not firm. Some functions and features can't be maintained. They are washed away after several times. ”Tang Fangqiong said, "We first wanted to solve the problem of durability and firmness."

On the basis of previous research, the joint team, guided by practical application, used the strategy of surface grafting and in-situ growth to modify the amino, carboxyl and other groups on the surface of wool fiber in a single molecular layer. These chemically modified groups can be firmly combined with nano silica particles, A nano thin layer of silica with a diameter of 20 nm was in-situ grown on the surface of wool fiber.

Members of the research team once went to the China Academy of Textile Sciences to study the "in-situ growth" of silica nano thin layer Wool fabric Test. According to the national standard, it is proved that it meets the requirements of "moisture absorption and quick drying" type Functional fabric It has the function of comfortable skin feeling and fast perspiration.

After being washed 20 times by washing machine, the fabric treated by this method can still maintain its "moisture absorption and quick drying" characteristics, which solves the problem that the current nano functional fabric is not washable enough.

Because the nano layer "grown" is very thin, the weight of the treated cloth increases by less than one thousandth of the original. "Therefore, the additional cost is small. Moreover, the in-situ growth strategy greatly simplifies the preparation steps, providing a new idea for large-scale construction of nano functional fabrics." Tang Fangqiong said.

"We mainly do research on nanomaterials, and always want to go out of the laboratory and put nanotechnology into practice. In cooperation with Hong Kong Polytechnic University, our initial idea is to invent a machine for preparing nanomaterials, so that the cloth can 'walk' through it once, and the nanomaterials can grow directly on the cloth." Tang Fangqiong said, "At present, we are cooperating with a textile enterprise in Jiangsu to process wool before it is woven into fabric, so as to improve the quality of wool fiber."

It is reported that the wet dyeing method commonly used for dyeing cloth is to soak the cloth in the pigment, then heat it to more than 90 degrees Celsius, take it out for drying after 30 minutes, wash off the floating color, and then dry it. The whole process takes more than an hour. There is also a process of surface grafting and in-situ growth to prepare nano layers, which also needs to be soaked, dried, and then placed in the nano solution to grow particles, and then dried. It will take about two or three hours from the beginning to "long" the cashier layer. This process can be combined with the textile dyeing and finishing process at the same time.

"The 'long' nano layer on the cloth has the function of 'moisture absorption and quick drying', so the cloth is easy to sweat. We used to combine titanium dioxide and silicon dioxide to prepare functional fabrics with self-cleaning and antibacterial effects. In theory, if it is made to be 'long' on a nano layer with functions such as flame retardant, waterproof, cold proof, anti ultraviolet and infrared ray, the fabric will have corresponding functions. ”Tang Fangqiong said.