Abstract: In order to cope with the complex environment faced during emergency rescue missions and meet the increasing demand for hydrophobic and acid alkali resistant properties of special protective clothing in extreme scenarios, it is imperative to develop fabrics with such functions. This study uniformly mixed chemically stable polytetrafluoroethylene (PTFE) with modified aluminum tripolyphosphate (ATP) to prepare a well dispersed PTFE ATP acid and alkali resistant agent. Through a two‒step impregnation coating method, PTFE ATP and polydimethylsiloxane (PDMS) were sequentially loaded onto the surface of the outer fabric of firefighting suits, and their surface morphology, wetting properties, surface solid liquid adhesion, acid and alkali resistance, thermal stability, breathability, and moisture permeability were characterized. The results showed that a dense and rough PDMS/PTFE‒ATP coating was formed on the surface of the fabric, exhibiting excellent hydrophobicity (contact angle of (151.92±1.34)°), extremely low adhesion between solid and liquid interfaces, and acid and alkali resistance (pH 1~14, contact angle of about 150°). No serious erosion or penetration was observed after 1 hour of contact with 96% concentrated sulfuric acid (H2SO4) or 30% sodium hydroxide (NaOH). The loading of PDMS/PTFE‒ATP coating has little effect on the thermal stability and moisture permeability of the fabric, and the modified fabric still maintains or even outperforms the commonly used outer layer fabric of firefighting suits in China in terms of breathability. This provides an environmentally friendly, innovative, and practical solution to address the threat of acid and alkali erosion on the outer fabric of firefighting suits.

Key words: two?step coating method, PDMS/PTFE?ATP, outer fabric of fire suit, hydrophobicity, solid?liquid interface adhesion, acid and alkali resistance