The main thermal and moisture properties that have to be offered by textile materials in clothing in typical work and leisure situations in the High North are protection from wet environment by water-proof outerwear, thermal protection from cold by excellent insulation properties, and good moisture properties to transport sweat away from skin. Recent developments that have improved the performance and functionality of clothing include porous and non-porous membranes for moisture permeability in water proof clothing, and improved moisture transport (wicking) provided by fibre microstructure and surface coatings. However, these solutions are not able to adapt the properties to the actual need of the wearer in changing environment. Incorporating stimulus responsive materials in textiles represent a revolution in the way garments provide thermal comfort. These materials undergo a reversible change in properties in response to an external stimulus.

Examples of such adaptive properties are temperature or moisture dependent permeability of air and water, and temperature dependent release of stored latent heat in phase change materials (PCM). These solutions offer great potential for improved comfort and work performance. The main obstacles for implementing this kind of adaptive solutions include:

• There is lack of knowledge on the robustness and degradation mechanisms of stimuli-responsive polymers.
  
• Documentation of working principle and performance of membranes that claim temperature or moisture dependent permeability are insufficient. There are examples of membranes appearing on the market which claim to have superior performance because they have temperature dependent vapour permeability. It has also been claimed that these changes in water vapour flux are primarily due to the relationship between temperature and the saturation vapour pressure of water. 
  
• Test and design methodology for stimuli-responsive materials are inadequate. In a stimuli-responsive material, there is no longer a single parameter describing the thermal (e.g. thermal resistance) or moisture (e.g. permeability) property of the material since these vary with temperature or moisture.

Such obstacles will be addressed by ColdWear. Another important goal is to provide an improved understanding of how the materials shall be used in accordance with the regulatory mechanisms of the body.