Preparation of Mechanically Robust Fluorosilane-Modified Polyurethane Electrospun Membranes with Waterproof and Breathable Performance

Abstract

To impart the waterproof ability and breathability to fabrics, a common practice is to modify the electrospun membrane with low-surface-energy materials. However, there has been few reports focusing on the effect of hydrophobic agent added into the electrospinning solution on the structure and performance of the membrane. Herein, we prepared the electrospun polyurethane (PU) membrane by adding two types of fluorosilane into the PU solution. The effects of fluorosilane type and concentration on solution conductivity, viscosity, fiber diameter, crystallinity, wettability, and breathability, were investigated. Results show that both solution conductivity and viscosity increase as the fluorosilane content increases. The dual effects of fluorosilane content exert opposing influence on the jet drawing process, which yields a minimum fiber diameter when the mass ratio of fluorosilane to PU is 20%. Under this condition, the electrospun membrane shows a highest water permeability, but a lowest breaking strength. Therefore, there is a trade-off between water permeability and breaking strength when designing a desirable fiber diameter. This study provides insights into fabricating the electrospun waterproof and breathable membranes with robust mechanical strength.

Keywords: polyurethane, fluorosilane, Electrospinning, Hydrophobicity, breathability