Robust and uniform ultrathin elastomeric films with complete surface covera
ge were fabricated from poly[styrene-b-(ethylene-co-butylene)-b-styrene] (S
EBS) functionalized with 2% of maleic anhydride by grafting to a chemically
modified silicon surface via epoxy-terminated self-assembling monolayers.
We varied the thickness L of the SEES film, from 1.4 to 8.5 nm, to test the
limits of the stability of microphase-separated structures under confined
conditions. We observed that the in-plane cylindrical/spherical microdomain
morphology is similar to the bulk microstructure but it is compressed in v
ertical direction due to film-air and film-substrate interfacial constrains
. Such a microstructure is formed at thicknesses in the range from 2.6 to 9
nm and is perfectly defined at L/L-0 = 0.3 (SEBS interdomain spacing, L-0
= 28 nm). Microphase separation is completely suppressed only for extremely
thin films with L/L-0 < 0.08. Unlike physically adsorbed SEES monolayers,
which dewet the silicon surface, tethered block copolymer monolayers obtain
ed under identical conditions are very stable even under high shear stresse
s and at elevated temperatures. (C) 2000 Elsevier Science Ltd. All rights r
eserved.