Temperature-sensitive polymer membranes were prepared by combination of shape memory
hydrophilic polyurethane (SMPU) and thermo-sensitive poly(N-isopropylacrylamide-co-sodium
acrylate) [poly(NiPAAm-co-SA)] hydrogel micro-particles through composite coating method. These
two intelligent polymer components endowed the composite membranes with “double switch” on the
water vapor permeability. Poly(NiPAAm-co-SA) hydrogel micro-particles exhibited a reversible volume
transition at lower critical solution temperature (LCST) around 34-36°C in the experiment. The size of
gel particles varied more than 10-fold between temperature above and below LCST. It is likely acted as a
sensor of temperature and as an switch to regulate the water vapor permeability of composite membranes.
Moreover, there was also a dramatic increase in water vapor permeability (WVP) with an increase in
temperature from 35 to 40°C for the shape memory hydrophilic polyurethane basement membranes.
Two different procedures for WVP test were employed to simulate different application situations of
the composite membranes. The temperature-sensitive water vapor permeability of composite polymer
membranes was investigated by varying the content of hydrogel micro-particles. All of the temperaturesensitive
membranes could have water vapor permeability controlled in response to temperature changes.