1. Introduction
With the rapid development of the electronic communication technology, the electronic devices became common in the daily life. Along with the development of the electronic communication, the electromagnetic (EM) radiation generated by the ubiquitous electronic devices also has a negative effect on the human life [
1]. The long-term exposure to EM radiation could endanger people’s health [
2,
3]. It was revealed that the various slight or serious negative effects on the human body have been investigated when someone has been near the mobile base station for a certain time. Additionally, the personal information stored, e.g., in credit cards and other electronic cards may be stolen by using near field communication (NFC) technology, which is based on the EM radiation [
4,
5,
6,
7]. To protect electrical equipment and human body from these damages, the fabrics with enhanced electromagnetic interference (EMI) have provided a solution. These fabrics were usually realized by incorporating the metal materials into the fabrics [
8,
9]. Shielding of EM waves was here achieved by the absorption and reflection of EM radiation in the metal-incorporated fabrics [
10,
11].
Various methods have been used for the preparation of metal-incorporated fabrics to enhance the EM shielding effectiveness (
SE), including the coating method (dip coating, the sputtering coating, the electroless plating…) and the weaving technology by using conductive yarns [
12,
13,
14,
15,
16]. Both the dip coating and the sputtering coating were convenient to prepare the EMI fabrics. The electroless plating technology was realized based on the autocatalytic deposition and simultaneous reduction where the metal ions in the bath were reduced with the catalyst and was suitable for the preparation of the ultralight EMI fabric [
17,
18,
19]. However, the coating technology altered surface chemistry and permeability of the fabric [
20]. The friction loss was also the factor affecting the lifetime coated fabric for EMI, which strongly depended on the bonding between the metal materials and the fibers. Furthermore, the surficial patterns of the metal-incorporated fabrics with EMI realized via the surface coating methods was significantly altered when compared with the uncoated fabrics, which strongly limited such metal-incorporated fabrics for the industry rather than the daily use. Besides, the moisture content in the room condition was also a factor to affect the stability of EMI fabric [
21]. Opposing to the various coating methods, the weaving method by using conductive yarns to prepare the EMI fabrics could provide a series solution for the problems. However, various research work focused on the effect of the porosity, thickness, yarns type and layers of the EMI fabrics on the final EM
SE [
9,
22,
23,
24,
25,
26,
27]. It was also concluded that the fabrics with conductive yarns were woven with basic structure, like plain, twill, honeycomb, end satin etc. Since the fabric structure was simple, the visible surficial patterns of the EMI fabrics were limited, which had less attraction for the customers. To date, there have been a few reports related to the complicated patterns on the metal-incorporated fabrics.
The Song Brocade fabric was based on the unique structure, which arose from the Song Dynasty of China [
28,
29]. The main materials for the Song Brocade fabric were the mulberry silk [
30]. The Song Brocade fabric was mainly fabricated based on the two traditional types of weaving [
29]. The weave of Song Brocade was weft backed, from two groups of warp and multiple groups of wefts. In details, one group was called the ground warp, which was made of refined and dyed mulberry silk, and the other group was called the face warp, which was usually made of a fine single raw silk. The ratio of the ground warp and face warp was mostly 3, and sometimes the ratio could be 2, 4, 6 etc. [
31]. Compared with the basic fabric structure, various patterns of the Song Brocade fabrics could be prepared by adjusting the number of the weaving cycles, including the pattern of ‘key brick’, ‘swastika’, and ‘shou’ etc. From this point of view, the weaving of the Song Brocade fabric by using the metal-incorporated yarns was the prospective alternative for the EMI fabrics.
In this work, two Song Brocade fabrics were successfully prepared. One was the Song fabrics woven by using the polyester (PET) yarns and the silk yarns, and the other one was woven by using the silver-plated polyamide (Ag-PA) yarns and the silk yarns. Two fabrics were fabricated with the same weaving structure where the ‘swastika’ (卐) appeared as the surficial pattern. The structure similarity of the surficial patterns of both samples were investigated via Python software [
32]. The EMI property and the ultraviolet (UV) shielding of both samples were evaluated. The surface resistance of both samples was also measured. Besides, the air permeability and the textile moisture evaporation rate of samples were measured.
4. Conclusions
In this work, the Song Brocade fabrics with and without Ag component were successfully fabricated. It was found that the incorporation of the Ag-PA yarns into the Song Brocade fabric did not affect the surficial pattern. It was found that the surface resistance of the Ag-PA yarn-incorporated Song Brocade fabric less than 40 Ω and was highly stable on both sides, which contributed to the excellent electromagnetic shielding with EM SE value higher than 54 dB. Since the Ag-PA yarn-incorporated Song Brocade fabric consisted of the Ag-PA yarns and two silk yarns, the specific shielding effectiveness and absolute shielding effectiveness were much lower. However, the well-distribution of the Ag-PA yarn in the Song Brocade fabric contributed to the high SE/t value. The practical test that the signal reading from the IC card covered by the Ag-PA yarn-incorporated Song Brocade fabric to the phone was totally failed, which corresponds to the results of the EMI analysis. The UPF values of the prepared two Song Brocade fabrics were higher than 195, which supported the excellent UV shielding effectiveness. Additionally, both the air permeability value and the water evaporation rate value of the Song Brocade fabric without Ag component was lower. The main reason was caused by the different yarn types in two fabrics.
Except for the sample with ‘卐’ as surficial pattern shown in this work, the other Song Brocade fabric type with Ag-PA yarns was shown in
Figure 13. The surficial pattern was more complicated, which consisted of the ‘flower’ shape and ‘卐’ shape. We proposed that the functional Song Brocade fabric could be applied in the personal protection and the industrial applications.