Breathable and Protective Fabrics Based On Carbon Nanotube Membranes

Ideal garments for simultaneous health hazard and heat stress prevention are lightweight clothing that combines high protection with excellent breathability. Conventional protective garments restrict evaporative heat loss, thus greatly limiting the main mechanism of human body thermoregulation in thermally stressing environments. Advancements in moisture-management performance of protective fabrics need new materials that are able to rapidly transport water vapor out and still provide a good degree of protection from harmful environments. Recently, in our laboratory, we have demonstrated exceptionally-fast gas and water flow rates in carbon nanotube pores (CNT). These results suggest that CNTs may sustain very large water vapor transport rates while maintaining a high degree of protection from biological and large chemical agents thanks to their very small, nanometer-sized diameter.

 To validate this concept, we have developed flexible, robust, and large-area membranes having vertically aligned CNT arrays as pores. SEM images indicate that well aligned CNTs are embedded in a flexible polymer matrix free of any macroscopic voids or structural defects. Our measurements show that our carbon nanotube membranes provide transport rates that are comparable to or exceeding state-of-art breathable fabrics at all relative humidities even if the moisture conductive pores are only 1-3nm wide. Moreover, CNT membranes have excellent wind-proof properties. Analyte rejection data for 1-2 nm CNTs show that 5-nm Au nanoparticles and 3-nm dyes are completely excluded by these pores, suggesting that CNT membranes will provide good protection from biological agents. Our results suggest that CNT incorporation in flexible polymeric matrices as selective, moisture-conductive pores may provide a breakthrough toward the development of next generation breathable and protective fabrics.