Preparation and characterization of the tensile hair artificial
muscles
For preparation of the tensile hair artificial muscles, the obtained
twist-stable double-plied hair fibers were wrapped around cylindrical
mandrels of different diameters tightly in clockwise and
counterclockwise directions respectively with both ends tethered. After
steaming for 30 min, the coiled hair muscles were untied from the
mandrel and relaxed in the open air. The fully relaxed hair muscles were
observed with a macro lens and imageJ was used to measure the coil
pitch. Differential scanning caborimetry spectra (DSC) for pristine hair
fibers, hair fibers heated for 30 min, and hair fibers steamed for 30
min were obtained on a TA differential scanning caborimetry (USA,
Q2000).