Liquid Permeation and Water Vapour Transmission Properties of a Temperature-Sensitive PVDF-g-NIPAAM Barrier Membrane

Both liquid chemical permeation rate of n-hexane and water vapour transmission rate (WVTR) of temperature sensitive polymer membranes made from N-isopropylacrylamide (NIPAAM) grafted Poly(vinylidene fluoride) (PVDF) copolymer (PVDF-g-NIPAAM) were studied in order to evaluate its potential utility as a smart barrier layer in chemical protective clothing. It is found that the breakthrough time in the chemical permeation test decreased when the copolymer membrane were produced in the mass ratio of NIPAAM:PVDF increased from 1:100 to 1:1, and the WVTR of the copolymer membranes made from higher concentrations of NIPAAM (i.e., 1:1 and 1:10 for the mass
ratio of NIPAAM:PVDF) at the environmental temperature (40°C) higher than the LCST of NIPAAM (32°C) was markedly greater than that at the environmental temperature (20°C) lower than the LCST of NIPAAM, it is believed that such characteristics is related to both the porous structure of the and the proportion of NIPAAM in the copolymers.