Amicrofluidicmanipulationsystem that can sense a liquid and control its flow is highly desirable. However, conventional sensors and motors have difficulty fitting the limited space inmicrofluidicdevices; moreover, fast sensing and actuation are required because of the fast liquid flow in thehollow fibre. In this study, fast torsional and tensileactuatorswere developed using hollow fibres employingspiralnonlinear stress, which can sense the fluid temperature and sort the fluid into the desired vessels. The fluid-driven actuation exhibited a highly increased response speed (27 times as fast as that of air-driven actuation) and increased power density (90 times that of an air-driven solid fibre actuator). A 0.5 K fluid temperature fluctuation produced a 20 degrees rotation of thehollow fibre. These high performances originated from increments in both heat transfer and the average bias angle, which was understood through theoretical analysis. This work provides a new design strategy for intelligent microfluidics and inspiration for soft robots and smart devices for biological, optical, or magnetic applications.

Design of amicrofluidicmanipulationsystem that can sense a liquid and control its flow is challenging. Here, the authors demonstrate fast torsional and tensileactuatorsusing hollow fibres employingspiralnonlinear stress which can sense the fluid temperature and sort the fluid into the desired vessels.