Lightweight cotton interlock knit (92%) with a thermosensitive polyurethane (PU) coating (8%). The surface color shifts from a soft violet to a neon pink when exposed to temperatures greater than 32 ˚C (89.6 ˚F). This thermochromic effect is highly reactive, switching colors quickly when the threshold temperature is reached. The coating is water-based, a unique offering in PU, and formaldehyde-free, lessening its environmental and human health impact during fabrication. Coated textiles are usually offered on heavier weights; however, by using a lightweight cotton base, the resulting fabric is only 150 gsm (4.4 oz/yd2) and retains a soft, skin-friendly, 100% cotton surface on the back. The coating has a combination of two pigments, one thermo-reactive and the other standard blended in the PU mixture. The coating is slightly aerated and the foamy mixture is applied to the textile with a scraping process that bonds the coating to the fabric surface. After application, the coated material is cured and finished with a heated calendar. Sold by the linear meter, the fabric has 130 cm (51 in) of usable width. The cotton backing is a bright white with the violet/pink PU face as the standard offering; however, a total of 19 colors of PU are offered. Multiple backing fabrics from the manufacturer’s collection can have the thermosensitive PU coating applied to the face, including jacquard, jersey, rib, fleece, etc. bluesignⓇ certification has been undertaken, approval pending for 2018. Applications include apparel, footwear, accessories, upholstery, and interior design.