Figure 4

AFM images of pH stimulus of PMAA nanodots.
Two corresponding AFM images of PMAA dots at pH 3.0 (a) and 9.0 (b) were scanned in the same region, illustrating the PMAA dot swelling and topomorphological evolution. The swelling volume factor estimated from unlabeled dots is 2.0, whereas that for the Arabic number labeled pairs of 1′/1 and 2′/2 is 5.0, for 3′/3 and 4′/4 is 10 and for 5′/5 is infinite. For the interpretation, please see the text.