Breathable Graphene Oxide‐Polymer Composite Membranes With Two‐Step Barrier Mechanism Against Nerve Agents

ABSTRACT Breathable membranes that reject chemical warfare agents (CWAs) are required for next‐generation protective apparel. A dual‐function graphene oxide (GO)‐polyamine architecture is introduced that addresses the long‐standing tradeoff between vapor transmission and CWA selectivity. GO‐polymer composite membranes were fabricated on polytetrafluoroethylene (PTFE) supports by pressure‐assisted filtration using ethylenediamine (EDA) to reinforce interlayer cohesion and a branched polyethyleneimine (BPEI) overlayer to introduce additional hydrogen‐bonding sites and charge‐rich domains. Various analytical techniques were used to verify crosslink formation and continuous multilayer architecture. The membranes sustain high water‐vapor transmission (WVTR >7000 g m − 2 day − 1 ) while strongly suppressing dimethyl methylphosphonate (DMMP) permeation; in the GO‐EDA‐PEI configuration no detectable breakthrough is observed. Tests with a live‐GD nerve agent yielded >95% blocking efficiency across all designs and >99% for GO‐EDA‐PEI, supporting effective protection across both vapor‐ and condensed‐phase exposure regimes. Under hydration and sonication stresses, EDA crosslinking together with the BPEI capping layer maintains high vapor permeability with strong CWA suppression, without the formation of dense polymer skins that typically compromise breathability. These results demonstrate that GO‐polymer composites can couple selective CWA resistance with high vapor transport and operational robustness, meeting practical requirements for protective garments and offering a scalable route to breathable barriers.