# Smart Textiles: A Review and Bibliometric Mapping
## 3 Results and Discussion
### Clusters of KW as indicators of research areas
Great efforts have already been made to improve the durability and washability of e-textiles, but there is still room for improvement by coating delicate parts of e-textiles with flexible and thin coatings that are resistant to moisture, water, wrinkling, and creasing during wear and textile care. **Cluster 3** (Blue) is organised around the keyword SMART FABRICS (occurrence 136), with 104 links and a total link strength of 106. The cluster presents smart fabric items that are designed for clothing from the viewpoints of textile technologies, specialized smart technologies and materials, as well as the design and properties of products. Examples of specific keywords with high occurrence (>10) include electrospinning, triboelectric nano-generators, energy harvesting, actuators, soft actuators, poly(3,4-ethylenedioxythiophene) (PEDOT), poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS), antennas, self-powered sensors, humidity sensors, thermoelectrics, thermal energy storage, embroidery, knitting, 3D printing, microencapsulation, smart materials, PCMs, nanofibres, conductive fibres, conducting polymers, artificial muscles, soft robotics, shape-memory alloys, shape-memory polymers, polyvinylidene difluoride (PVDF), liquid metal, piezoelectric, self-powered, photoluminescence, electrical properties, thermoregulation, thermal comfort, rapid prototyping, design process, and innovation. Cluster 3 is oriented toward smart fabrics, which are only one of the segments of smart textiles. Fabrics can be woven, knitted, or non-woven, and thus, technologies such as knitting, weaving, electrospinning, embroidery, and 3D printing can be used to create smart fabrics. Advanced materials, such as conductive yarns or wires made from shape-memory alloys, can be incorporated into the fabric structure, while shape-memory polymers (SMPs) can be used to produce shape-memory fibres, shape-memory yarns or shape-memory fabrics. The latter may also be made by coating a shape-memory emulsion or shape-memory film. SMPs and their composites deform back to their original shape after severe deformation due to Joule heating, magnetism, moisture, light, or solutions. The response of SMP composites depends on the type of filler (carbon particles, CNTs, a mixture of CNTs and PVDF, carbon fibres, electromagnetic fillers, hybrid fibres) or the embedding of an optical fibre. Conductive polymers such as PEDOT or PEDOT:PSS can be used to make physical sensors for humidity, temperature, pressure, and strain. Piezoelectric plastic materials such as PVDF can generate electrical charge when mechanically deformed. Theyare often used for health monitoring. The application of PCMs to textiles usually requires microencapsulation of the PCMs and then the application of microcapsules to the fabric by coating or printing. Such a fabric responds to temperature and enables a thermoregulatory effect that ensures the thermal comfort of the wearer. Smart textiles require energy to maintain the sensors and actuators. An alternative device for energy harvesting is the triboelectric nanogenerator, a mechanical harvester based on triboelectricity that harvests electrical energy from the mechanical energy of the environment. The advantages of triboelectric nanogenerators are high instantaneous output power, an environmentally friendly, low-cost manufacturing process, and different operating modes tailored to target applications. In addition, the use of self-powered sensors or self-powered devices can reduce the need for additional devices for energy harvesting. Cluster 4 (Yellow green) is focused on Wearables (occurrence 210), with 151 links and a total link strength of 193.