Evaluating post-anneal stretch on twisted and coiled actuators for compression therapy in textiles

Coiled nylon 6,6 actuators are compact (600-µm diameter), have reversible contractions between 5-20%+, and exhibit a work density 100x greater than that of human muscle. This study investigates the effect of post-anneal stretching of coiled nylon actuators on compression pressure in Nomex-based prototypes designed for compression therapy. Coiled nylon actuators were integrated into three prototypes, each with actuators stretched by 14%, 28%, and 42%. The prototypes were tested on solid and silicone calf models to assess pressure generation. Results showed that a 14% stretch provided consistent compression, while higher stretches led to reduced performance or mechanical failure. These findings contribute to the development of actuator-integrated compression textiles.