W. Richard Bowen and Nidal Hilal 4

Y Range: 1.21 μm
(a)
0.205
–1.00 –0.399
8.5 STAR-SHAPEd POLyMERS AdSORBEd ON SURFACES 239
Height range: 2.234 nm
1.03 1.63 2.24
X Range: 1.21 μm
Y Range: 1.21 μm
(c)
–1.71 –1.11
–2.32
2
1.6
1.2
0.8
0.4
Height range: 5.050 nm
–1.26 –0.652 –0.0473
X Range: 1.21 μm
adsorbed amounts, no interpenetration and fusion were observed. The star
polymers continued to keep their individuality and they formed isolated
globules upon the evaporation of the solvent.
In Figure 8.14, we compare the overall monolayer organisation for
long incubation times. Such incubation times are long enough to achieve
the maximum adsorbed amount (within our adsorption protocol using
dilute polymer solutions). The 18-arm star polymers organised in discontinuous
asymmetric islands, which consist of several individual polymer
chains; it is clear that the star polymers penetrated each other when in
good solvent and they collapsed in groups upon drying. The 32-arm star
polymers also penetrated each other and they self-assembled in a continuous
dense network. On the other hand, the 59-arm star polymers did
Y Range: 1.21 μm
(b)
–0.56 0.0452 0.65
Height range: 10.03 nm
–2.59 –1.98 –1.38
X Range: 1.21 μm
FIgurE 8.12 AFM topography images of star polymers adsorbed on mica: (a) 18 arms,
incubation time of 5 min; (b) 32 arms, incubation time of 10 min and (c) 59 arms, incubation
time of 180 min.
10
7.5
5
2.5
5
4
3
2
1