Interlaced Amphiphobic Nanofibers for Smart Waterproof and Breathable Membranes with Instant Waterproofness Monitoring Ability

Abstract

Electrospun nanofiber-based waterproof and breathable membranes (WBMs) that can provide a high level of protection and excellent air permeability and functionality are becoming promising core materials in numerous fields. However, large challenges still remain in the facile preparation of high-performance and smart WBMs capable of forecasting the failure of waterproof protection. Herein, amphiphobic TPU/PVDF-HFP nanofiber membranes with an interlaced fibrous structure are prepared by a one-step multineedle electrospinning technology. The obtained membranes demonstrate outstanding waterproofness with a hydrostatic pressure of over 108 kPa, a high air permeability of over 10 mm s^–1, and a water vapor transmission rate (WVTR) of 8.40 kg m^–2 d^–1, as well as excellent mechanical properties with a tensile strength of 6.07 MPa and a tensile strain of 117.11%. These make them extremely suitable for WBM applications. More importantly, due to the robust interlaced fibrous structure and the piezoelectric property of PVDF-HFP, the hydrostatic pressure of the TPU/PVDF-HFP membranes can be easily monitored and predicted by measuring the voltage output, indicating excellent hydrostatic pressure monitoring capability. The addition of low-surface-energy chemical materials endows the membranes with durable amphiphobicity against various harsh conditions, which further enhances the waterproof property. Such versatile nanofiber membranes would be desirable for potential applications in protective clothing and wearable electronic products and would provide a source of inspiration for the fabrication of smart WBMs.