Phase-change materials: from NASA to your bed

Phase-change materials were originally developed for NASA in the 1980s. The challenge: astronaut gloves needed to maintain comfortable hand temperatures across extreme thermal cycling — from direct sunlight (+250°F) to shadow (-250°F) during spacewalks.

The solution was micro-encapsulated paraffin wax, sealed in polymer shells just 2-30 micrometers in diameter. These capsules absorb thermal energy as the wax melts, and release it as the wax solidifies — passively regulating temperature within a precise range.

Solène uses a next-generation PCM formulation calibrated for the human body: our capsules begin absorbing excess heat at 87°F (the typical skin surface temperature during a hot flash) and release stored energy at 72°F (comfortable sleeping temperature).

The capsules are woven into the core layer of each sheet — not applied as a surface finish. This means the cooling properties are permanent and will not wash out. Independent testing confirms no measurable degradation after 200 machine wash cycles.