An experimental investigation of strain rate, temperature and humidity effects on the mechanical behavior of a perfluorosulfonic acid membrane

► Time-dependent mechanical behavior of Nafion® 211 membrane is investigated. ► Response is more sensitive to change in strain rate or temperature than to change in humidity. ► Steady state swelling behavior of the membrane is experimentally investigated. ► Little or no hygro-thermal history effect on the swelling strains is reported.