Constructing a Fluorine-Free, High-Temperature-Resistant, Waterproof, and Breathable Membrane with Enhanced Mechanical Properties, Combining Dilute Solution Welding and Silane Treatment

Abstract

Advanced packaging materials are required to isolate moisture and maintain the internal stability of flexible wearable electronic devices. To address the limitations of traditional materials, poor mechanical strength, lack of thermal stability, and insufficient air permeability, packaging materials with high-temperature stability, strong waterproofness, and sufficient moisture permeability need to be developed urgently. In this study, an innovative method combining electrospinning, dilute solution welding, and hydrophobic finishing was used to prepare a high-temperature resistant, waterproof and breathable membrane with improved mechanical properties. This strategy involves the use of a polyimide membrane as the substrate and it improves interfibrillar bonding by means of dilute solution welding. A polydimethylsiloxane postfinishing process was used to construct the hydrophobic interface. This design exhibits excellent air permeability (22.03 ± 0.25 mm·s^-1), appropriate hydrostatic pressure (65.99 ± 0.70 kPa), and notable high-temperature resistance and durability: after being treated at a high temperature of 350 °C, the tensile strength still reached 8.20 ± 0.26 MPa, and the hydrostatic pressure drop was only 11.71%. After 50 standard water-washing cycles, the water vapor transmission rate decreased by only 4.68%, and dimensional stability and functional integrity were maintained. These membranes have broad prospects for electronic component packaging.

Keywords: electrospinning; enhanced mechanical properties; flexible packaging materials; high-temperature resistance; polyimide; waterproof and breathable; welding.