A person’s body temperature is an important indicator of their health status. A deviation of that temperature by just 2 °C already has or can lead to serious consequences, such as fever or hypothermia. Hence, the development of a temperature-sensing and heatable yarn is an important step toward enabling and improving the monitoring and regulation of a person’s body temperature. This technology offers benefits to several industries, such as health care and sports. This paper focuses on the characterization and development of a hybrid yarn, which can measure and visualize temperature changes through a thermoresistive and thermochromic effect. Moreover, the yarn is able to serve as a flexible heating element by connecting to a power source. The structure of the yarn is designed in three layers. Each layer and component ensures the functionality and flexibility of the yarn and additional compatibility with further processing steps. A flexible stainless steel core was used as the heat-sensitive and heat-conducting material. The layer of polyester wrapped around the stainless steel yarn improves the wearing comfort and serves as substrate material for the thermochromic coating. The resulting hybrid yarn has a reproducible sensory function and changes its resistance by 0.15 Ω between 20 and 60 °C for a length of 30 cm. In addition, the yarn has a uniform and reproducible heating power, so that temperature steps can be achieved at a defined length by selecting certain voltages. The thermochromic color change is clearly visible between 28 and 29 °C. Due to its textile structure, the hybrid sensory and actuating yarn can easily be incorporated into a woven fabric or into a textile by means of joining technology sewing.

Anion exchange membrane water electrolysis (AEMWE) is a promising technology for sustainable hydrogen production. It combines the advantages of alkaline and proton exchange membrane electrolysis, and enables the use of abundant catalyst and structural materials. While significant progress has been made in catalyst development, porous transport layers (PTLs) have received comparatively little attention, despite playing a crucial role in controlling charge transport, reactant distribution, gas removal and overall cell efficiency. This review provides a comprehensive overview of the current state of PTL research for AEMWE, emphasising the relationship between structural design and electrochemical performance. First, the review discusses the fundamental transport mechanisms and functional requirements of PTLs, highlighting the interplay between porosity, pore size distribution, tortuosity, wettability, electrical conductivity, mechanical stability and corrosion resistance. Next, recent advances in PTL materials are critically assessed, including nickel-, stainless steel-, titanium-, and carbon-based systems, as well as structural concepts such as foams, fibre-based materials, wire meshes, additively manufactured architectures, and surface-engineered transport layers. Finally, the review identifies current challenges regarding structural optimisation, long-term durability, standardised evaluation protocols and scalable manufacturing. The analysis suggests that future progress in AEMWE will increasingly depend on rational PTL engineering rather than on catalyst optimisation alone. The development of multifunctional, hierarchically structured transport layers with tailored transport pathways is expected to play a key role.