# Recent Advances in Fiber-Shaped Electronic Devices for Wearable Applications
## 4 Integrated Smart Electronic Textiles  
Integrated wearable systems offer promising opportunities to continuously monitor a user's surrounding environment and health. Furthermore, they facilitate communication, external-environment sensing, and power generation and supply. Recent research has focused on combinations of processors, sensors, displays, and energy systems to provide more reliable and accurate information [46]. The fiber-shaped device structure provides attractive possibilities in electronics. For example, electronic fibers could be integrated into a single device that could convert human/environmental information into electrical signals and then process those data. When the electrical fiber components are woven together into e-textiles, they are connected in parallel or series to improve the output current and scale-down. Although 1D electronic devices output a limited current, an integrated system could maximize the electrical performance. The multi-functionalization and integration of 1D devices are required if e-textiles are to have broad applications. For instance, an integrated fiber-shaped supercapacitor and sensor could monitor the wearer's health and external environment without requiring an external power source. Accordingly, self-powered electronic devices have also attracted considerable attention due to their potential for application in wearable monitoring technology and personalized intelligent systems [81, 82]. Two fiber-shaped devices could be twisted to produce a 1D electronic system and then integrated by connecting a common electrode to form a 2D configuration that can function as both an energy harvester and an electronic device. Such a design strategy represents one promising avenue for future electronics. Although other considerations, such as comfort and washability, are important for wearable electronics, the performance and function of integrated e-textiles is already advancing. As a bridge to interaction in human-portable devices, display textiles offer a real-time communication function that could help reduce a user's difficulties in speech or speaking [66]. Recently, [PERSON] et al. wove a large-area display textile based on electroluminescent units formed at the werf-warp contact points within the fabric (Figure 8a) [20]. The solution-processed luminescent warp and conductive werf fibers contained ZnS phosphor dispersed in an insulating polymer, and ionic-liquid-doped polyurethane gel, respectively [20]. A multifunctional integrated textile system was then demonstrated by weaving that display textile with a fiber-based keyboard and power supply (Figure 8b) [20]. This integrated e-textile showed useful communication and interactive navigation display functions (Figure 8c) [20]. Such smart textiles could be used as wearable communication tools in the future. Wearable sensory interfaces that can record, model, and understand human-environment interactions are important in the development of wearable healthcare and robotics. [PERSON] et al. combined fiber-shaped sensors with machine learning to process and interpret a mass of tactile data [83]. The piezoresistive fibers comprised 3-ply stainless-steel threads coated with graphite nanoparticles, copper nanoparticles, and polydimethylsiloxane elastomer [83]. The functional fibers in a core-sheath structure could be woven into large-scale textiles using digital machine knitting (Figure 8d) [83]. To learn diverse human-environment interactions through tactile textiles, computational workflows based on AI have also been developed [83]. The AI-powered smart textiles can classify the sitting poses and motions of their human users (Figure 8e) [83]. The demonstration of tactile learning using a textile platform is expected to be applicable to cognitive science and the imitation learning of intelligent robots [83]. Using existing technology, e-textiles have been fabricated through complex and delicate multistep processes, the costs of which are very high.