Poly(N-isopropyl acrylamide)/chitosan composite membrane with smart thermoresponsive performance

In this study, poly(N-isopropylacrylamide)/chitosan (PNIPAAm/CS) composite membranes with different weight ratios were fabricated using a one-step method, in which PNIPAAm was directly synthesised using NIPAAm monomers by means of free radical polymerisation. Fourier transform infrared spectroscopy and X-ray diffraction were employed to characterise the interactions. The lower critical solution temperature (LCST) of the swollen membrane was determined by differential scanning calorimetry. The morphologies of the obtained membranes were observed using SEM. The results showed that there was hydrogen bonding formed between CS and PNIPAAm. The LCST of the PNIPAAm/CS membranes was about 31.3-31.8 degrees C. Obvious phase conversion and shape change of the composite membrane can occur below and above the LCST, indicating that when the weight ratio of PNIPAAm to CS is 7 : 3 to 5 : 5, the composite membranes have the potential to be used as a smart artificial skin or wound dressings.