la0c01785_si_001.pdf (209.37 kB)
Surface Segregation of a Star-Shaped Polyhedral Oligomeric Silsesquioxane in a Polymer Matrix
journal contribution
posted on 2020-08-07, 15:43 authored by Kentaro Yamamoto, Daisuke Kawaguchi, Tatsuki Abe, Takeshi Komino, Masashi Mamada, Taizo Kabe, Chihaya Adachi, Kensuke Naka, Keiji TanakaA simple
way to control only the surface properties of polymer
materials, without changing the bulk properties, has long been desired.
The segregation behavior when a component with a tiny amount fed into
the matrix is thermodynamically enriched at the surface is one of
the candidate methods. This capability was examined herein by focusing
on a star-shaped polyhedral oligomeric silsesquioxane (s-POSS), where
the central POSS unit is tethered to eight isobutyl-substituted POSS
cages as a surface modifier. X-ray photoelectron spectroscopy revealed
that the surface of a film of poly(methyl methacrylate) (PMMA) was
almost completely covered with POSS units by adding just 5 wt % s-POSS
to it. The segregated POSS dramatically altered the physical properties
such as molecular motion and the mechanical and dielectric responses
at the surface of the PMMA film. These findings make it clear that
s-POSS is an excellent surface modifier for glassy polymers.