Polymer stiffness and stretchability decoupled with molecules that release stored length

https://engineering.virginia.edu/news-events/news/major-materials-breakthrough-uva-team-solves-nearly-200-year-old-challenge-polymers

"heating natural rubber with sulfur creates crosslinks between rubber molecules, transforming sticky rubber into durable, elastic vulcanized rubber... now, foldable bottlebrush polymer networks enable stretchable/ stiff rubber... bottlebrush polymers' backbone collapses/ expands, extra length inside uncoils, allowing up to 40X elongation, side chains determine stiffness... 3D-printable, can add conductive nanoparticles... prosthetics, medical implants, wearable electronics, robotics that repeatedly flex, bend, stretch"