**6.3. Textile application of SMPU**

SMPU can be made in the form of fibers (macro-, micro-, and nanofibers), solutions, films, and foams for textile and apparel applications, such as non-woven materials, coatings, finishing, lamination, weaving, and knitting [46–49]. Various methods such as wet spun, melt spun, dry spun, and electrospun are used for the production of SMPU fiber [50–53].

Shape memory films and foams have a number of applications in laminated smart fabrics [54, 55]. The functions of SMP films applied to textiles include waterproofing, water vapor permeability (WVP), seam sewing, crease recoverability, and crease fixing [56, 57]. SMPU has a potential for making breathable fabrics due to its good WVP sensitivity. Jeong et al. studied the WVP properties of SMPUs, and breathable fabrics were invented by coating the SMPU membranes on a fabric substrate [26]. Mondal and Hu also designed SMPU-coated fabrics, which abruptly increased WVP properties at room temperature (*T*<sup>r</sup> ) compared to low temperature [58]. These results suggested that the breathable textiles require possessing a high WVP at higher temperatures and a low WVP at lower temperatures. Additionally, Mondal and Hu incorporated a small percentage of carbon nanotube in SMPUs and then coated on cotton. They reported that the fabricated cotton fabric provided excellent UV protection, along with a required WVP and wearing coziness [58]. In addition to that, Chen et al. also investigated adjusting the size and shape of the free-volume holes in a fabricated membrane to control the WVP by adjusting the temperature [59]. Further, Mondal and Hu attempted to find the influence of hydrophilic groups and crystalline soft segments on the WVP of SMPU films [60]. They found that the WVP increased with the increase of PEG due to the enhancement of hydrophilicity. However, PCL or polytetramethylene glycolbased SMPUs have low WVP because of the increased interaction among the polymer chains.

Hu et al. also fabricated a fabric-based thermoelectric generator using coating of waterborne PU composite on yarn [61]. They reported that this coated fabric showed satisfactory thermoelectric performance and good processability. In addition to that, medical stockings are also fabricated using SMPU for the treatment of chronic venous disorders [62–64]. This SMPUbased stocking allows controlling or managing the pressure exerted in a wrapped position and also produces extra pressure (up to 50%) by simply heating the stocking. This type of stocking possesses a great potential to overwhelm the restriction of conventional stockings. It can be used as a smart wound-care product, during the course of compression therapy. Selfhealing textiles are also developed using SMPU. In this context, Hu et al. fabricated stimuliresponsive fiber using SMPU which showed 94% healing efficiency [65].
