20i nm

 10 nm

 0 nm










Figure 4-19. Topographic AFM images of the star-shaped PEO-b-PCL copolymers LB films
 transferred below and above the pseudoplateau: Star#1 at 10 (a) and 30 mN/m (b);
 Star#2 at 10 (c) and 30 mN/m (d); Star#3 at 10 (e) and 30 mN/m (f); Star#4 at 10 (g)
 and 30 mN/m (h); Star#5 at 10 (i) and 30 mN/m (j); Star#6 at 10 (k) and 30 mN/m (1).


 From the previously reported literature, the PCL crystal unit cell has a length of 1.7297 nm

that corresponds to two e-caprolactone repeat units.142 PCL crystal thickness after transfer is

around 7.5 nm for all the star-shaped block copolymers, and if it is assumed that the PCL chains

orient perpendicularly to the mica substrate, this thickness indicates that the chains fold

approximately every eight e-caprolactone repeat units. This would also support why the stars

with a number of e-caprolactone repeat units per PCL chain greater or close to eight all

crystallized (Star#6, Star#5, Star#4, Star#3, and Star#2), whereas Star#1, with only three repeat

units per PCL chain, did not.

 Similarly as for PCL homopolymers, the star-shaped samples exhibited PCL crystals at

low and high pressures, before and after crystallization of the PCL block at the A/W interface.