Investigation of a stimuli-responsive copolymer by atomic force microscopy

The aim of this study was to investigate the stimuli-responsive behaviour o f a pH- and temperature sensitive polymer system, i.e. a random copolymer o f N-isopropylacrylamide and acrylic acid by atomic force microscopy (AFM). AFM allowed high resolution images of the physical states of the polymer ch ains at different conditions. Different collapsed and extended chain confor mations of a random copolymer were seen over a wide range of pH and tempera ture. The shapes of both the individual copolymeric chains and globules can be clearly identified. Here we demonstrate the potential of AFM for charac terising the stimuli responsive behaviour of such "smart" polymers. (C) 200 0 Elsevier Science Ltd. All rights reserved.