Bioinspired Multifunctional Spindle‐Knotted Microfibers from Microfluidics

Heterostructured microfibers with spindle-knots and joints are developed using a novel microfluidic technology, which enables integrative microfiber joint spinning, fluid coating, and knot emulsification. The knots emulsification process can be precisely tunable by adjusting the flow rates. In this way, the size and spacing of the spindle-knots of the microfibers can be achieved with high controllability. More attractively, the construction process benefits from the broad availability of the coating fluids, which determines the compositions of the knots. Thus, the resultant microfibers are imparted with distinctive functions, such as humidity-responsive water capture, thermally triggered water convergence, induced colloidal crystal assembly, and cell microcarrier arrays. These features make such microfibers highly versatile for use in diverse applications.