# Smart Textiles: A Review and Bibliometric Mapping
## 3 Results and Discussion
### Clusters of KW as indicators of research areas
The use of dry electrodes, which include textile electrodes, is more suitable for daily and long-term use, as dehydration due to electrolyte deficiency does not occur. These types of electrodes are especially desirable for EMG recording. The classic antenna on textiles is nowadays replaced by a textile antenna whose task is to communicate between the sensor and the external device. Wearable antennas must be flexible, lightweight, washable, and robust. They enable wireless communication between the body network, where the user's physiological data is collected, and the health centre. **An overview of new trends--the latest concepts and propulsive research topics**  
When considering the time dimension, certain general keywords seem to be more important and used more frequently at the beginning of the observed period (e.g., wearable computing, smart materials, protective clothing), while specific terms such as wearable sensors, wearable electronics, and textile electrodes became typical in the middle of the observed period. Research topics such as liquid metal, MXenes, textile electronics, and triboelectric nanogenerators have gained importance in recent years. The overlay visualisation of the authors' keywords is shown in Figure 12, where the colour of the circles is determined by the average publication year of the documents in which the authors' keyword appears. A colour bar displayed in the lower right corner of the visualisation ranges from blue (oldest average publication year) to green and yellow (newest average publication year). Figure 12: Overlay visualisation of authors’ keywords in the field of smart textiles, with the time component. To further explore trends in the field of smart textiles, the most recent keywords with an average publication year younger than 2020 were identified and further examined in new scientific publications. The most recent keywords with at least 10 occurrences are listed in Table 5 and are presented in the following text as **hotspots of recent research**. **Liquid metal**. Liquid metals possess unique properties in ambient environments, such as fluidity, high conductivity, and intrinsic stretchability. In smart textiles, they have been applied in chemical sensors, wearable electronics, and stretchable devices [127]. Elastic liquid metal-based triboelectric fibres can harvest mechanical energy via the triboelectric effect and have been applied as power sources for wearable electronics and functional textiles [128]. Conductance-stable liquid metal sheath-core microfibres are appropriate for the production of stretchy smart fabrics and self-powered sensing [129]. Liquid metals can be 3D printed to produce interconnects in stretchable electronics [130]. **MXenes**. MXenes are two-dimensional inorganic nanomaterials consisting of atomically thin layers of transition metal carbides, nitrides, or carbonitrides. Due to their excellent electrical conductivity, enriched surface functionalities, and large surface area, MXenes have been used as building blocks for next-generation wearable electronics, flexible electronics, and in combination with fibres, yarns, fabrics, and smart textiles. MXenes enable wearable smart textiles for energy storage, power generation, strain and humidity sensing, EMI shielding, Joule heating, healthcare, and biomedical applications [7,131]. **Textile electronics**. Textile electronics contain fibres or fibre assemblies with electronic functions for the generation, transmission, modulation, and detection of electrons. Their characteristics include high performance, light weight, handiness, flexibility, comfort, and low strain under severe deformation [132]. A new generation of 1D fibre-shaped electronics has been applied in devices for energy harvesting, energy storage, light emission, and sensing. They are small in diameter, lightweight, flexible, and can be fabricated into soft textile electronics [133]. **Self-powered**.