Rifled microtubes with helical and conductive ribs for endurable sensing device

Helical fibers represent of one of the most extraordinary objects in living organisms and have recently produced through a coaxial microfluidic spinning process. But the requirement of collection capillaries may limit scalable production because of blockage liability, structural rigidity and cumbersome fabrication of capillary. Structural vulnerability of helical fibers could also limit their practical applications, e.g., in fabric and as wearable devices. Herein for the first time we showed that helical fibers could be produced solely with a core steel needle with double concentric sleeves through a coaxial wet spinning process, without the requirement of microfluidic spinning capillary. They were encapsulated into protection microtubes in an unprecedented form of rifled microtubes with helical ribs. The presence of protection microtubes promote not only their mechanical properties, but also structural endurance to various practical circumstances. These rifled microtubes could serve as endurable and sensitive wearable strain/stress sensors (up to ∼300% strain and ∼100 kPa stress) to monitor various human motions, without showing conspicuous performance decay even after >104 cycles of measurements. This study offers not only a facile and scalable pathway of producing helical fibers, but also an unprecedented platform of rifled microtubes as endurable and sensible sensors of strain and pressure.