This invention discloses a motion-responsive waterproof and breathable crimped
fiber membrane, its preparation method, and its applications. The
fiber membrane is a composite
fiber membrane composed of nanofibers, which include
polyurethane, a low-elasticity
fluorine-free
polymer, and
polydimethylsiloxane. The fiber membrane has a three-level elastic structure. In its unstretched state, the fiber membrane has a first average pore size of 0.3 μm ≤ D1 ≤ 1.2 μm and a first
moisture permeability. When subjected to a
tensile strain of 20%–50%, it has a second average pore size of 1.2 μm < D2 ≤ 2.5 μm and a second
moisture permeability, with the second
moisture permeability being higher than the first. This invention achieves, for the first time, a
direct response of the fiber membrane to mechanical motion, i.e., waterproof in static conditions and highly permeable in dynamic conditions. It possesses advantages such as being
fluorine-free and
environmentally friendly, dynamically breathable, and highly resilient, and has broad application prospects in outdoor sportswear, medical protective equipment,
aerospace, and other fields. The preparation of this fiber membrane requires no post-
processing or additional
processing steps, and the process is simple and highly controllable.