Widespread electromagnetic radiation is the byproduct of the mass adoption of electronic devices and wireless systems. This unwanted energy radiation triggers a crosstalk between electrical and electronic equipment, eventually causing all of them to malfunction. Over-exposure to such radiations is also harmful to human health. Providing solution to this problem is, therefore, a top concern for researchers and industry players. One of the ways of containing electromagnetic radiation is using a shield that can efficiently handle free charges within a circuit. Metallic gaskets have long been a part of the process; now designers agree that fabric shielding is a more viable solution. Of all the fabric types, textile has caught the attention of researchers in a big way, thanks to the versatility of this material. This physical attribute enables it to integrate with different structures. This article offers a brief introduction to various types of textile and how they work to control electromagnetic interference. But first, let us explain the unique physical features of textile and why scientists think it is fit for combating EMI.
Artificial fibers such as polyester, polyamide, polyacrylic, and cellulose are highly hydrophobic, which means they accumulate a lot of static electricity. This kind of deposition can be dangerous with unwanted electrical consequences. This phenomenon can be avoided by using fabric that has a high electrical conductivity. Ordinary materials are not endowed with such attributes and usually, need some metal blending to get shielding-ready. But not just any metallic fibers make a practical option for shielding since they show a tendency to break when used—an aspect that affects the conductivity of the fiber. Also, they are not fit for easy blending with organic polymer fibers. Metal-plated textiles seem to overcome these challenges.
Metalizing Textile Fabric
Copper, nickel, silver and their alloys are extensively used across the industries to manufacture EMI-shielding-ready textile fabrics. These metalized textiles combat EMI by reflecting the radiations and not by absorbing them. However, for a wide range of applications, this attribute is not considered adequate and therefore, scientists have innovated fabric materials that can absorb electromagnetic radiation. In recent years, the market is inundated with textile products featuring ferromagnetic properties. These products are mostly used as flexible screens in a host of commercial applications such as motors and transformers. They are also used as filters capable of freeing air and water of their magnetic properties. Ferromagnetic textile fabrics that are created by incorporating fiber polymers on their surfaces are the perfect examples of these types of metal-mixed textile shields.
Coating Textiles With Conductive Polymer
This latest technology has taken the world of EMI shielding by storm. With a superior chemical memory and a highly reversible redox property combined with a corrosion-protective capability, it is used in a variety of industrial applications such as energy storage, molecular recognition, and optoelectronic devices. Due to these physical attributes, these fabrics provide better shielding efficiency than metal fiber and composite materials. The latter group of materials is less efficient due to its susceptibility to galvanic corrosion or friction-related conductivity loss.
Improving Shielding Efficiency With Nonwovens Textiles
In the frequency range of 100 to 800 MHz, nonwoven textiles such as polypyrrole-coated polyester show a great result in achieving shielding efficiency. Their shielding effectiveness can be attributed to their surface conductivity. In fact, nonwoven textile materials with electro-conductive coatings can achieve a shielding efficiency above 15 dB. To further increase its shielding effectiveness, it is often mixed with stitch-bonded electro-conductive fibers, while polymer coatings containing various inorganic compounds work as absorbers.
Long-term exposure to electromagnetic radiation can have dangerous consequences for both humans and machines. No wonder, scientists are coming up with a variety of electromagnetic shielding fabrics and gaskets for a wide range of applications. The use of textile fabrics as valuable EMI shielding material is the latest approach to be included in the mix. In recent years, scientists are incorporating various types of substances apart from copper, silver or carbon particles into textiles to increase their shielding efficiency.