Double stimuli-responsive membranes grafted with block copolymer by ATRP method

Double stimuli-responsive regenerated cellulose membranes have been prepared using atom transfer radical polymerization (ATRP) method. Firstly, the ATRP initiator of 2-bromoisobutyryl bromide was anchored on the surface of regenerated cellulose membranes. Then acrylic acid (AAc) and N-isopropylacrylamide (NIPAAm) were grafted onto the membrane surface step by step using ATRP method. The grafted chain length could be controlled by polymerization time. The uniform chain length could make the grafted copolymer (P(AAc)-b-P(NIPAAm)) as clear and different aggregate phase. So, the double stimuli-responsive property of block copolymer grafted membrane was distinct. Also, the results showed that the stimuli-responsive property of membrane was not a simple adding of two different stimuli-responsive properties, such as pH-responsive and thermo-responsive but more complicated responses to the changes of pH values and temperatures because of the reciprocity of different molecules. In this paper, the membrane was characterized by XPS, ATR-FTIR, TGA and SEM. The double stimuli-responsive properties of grafted membranes were measured by water flux measurement.