The surface chemistry of two systems of block copolymers
was studied using angular dependent X-ray Photoelectron
Spectroscopy
poly(dimethyl
(XPS). Surface concentration
siloxane-b-sulfone)/polysulfone
profiles of
[PDMS/PSF]
blends cast at several rates of solvent evaporation, and cast
on several substrates were measured. Surface concentration
profiles of poly(styrene-butadiene-styrene)
poly(styrene-isoprene-styrene) [SIS] triblock
[SBS] and
copolymers
cast at several rates of solvent evaporation, and cast from
two different solvents were also measured. The concentration
profile analyses were made using three different XPS
quantification techniques. The PDMS/PSF systems were analyzed
using the peak area ratio, and the SBS and SIS
copolymers were analyzed using both the Cls shakeup to main
ratio, and spectral measurements of the valence band. The
results of this study indicate a variation in surface concentration
as well as concentration gradient for different
sample preparation routes. The variations can be explained by considering the rate of film formation (kinetics), polymer
- solvent interactions, and polymer - substrate interactions.
However, in both systems the lower surface energy copolymer
block (siloxane block, or diene block) preferentially segregated
to the surface for all of the sample preparation routes
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