ma7b01843_si_001.pdf (1.96 MB)
Capillary Imbibition, Crystallization, and Local Dynamics of Hyperbranched Poly(ethylene oxide) Confined to Nanoporous Alumina
journal contribution
posted on 2017-10-18, 16:51 authored by Yang Yao, Yasuhito Suzuki, Jan Seiwert, Martin Steinhart, Holger Frey, Hans-Jürgen Butt, George FloudasThe
crystallization and dynamics of hyperbranched poly(ethylene
oxide) (hbPEO), obtained from the direct random copolymerization
of EO and glycidol (PEO-co-PG), are studied both
in bulk and within nanoporous alumina (AAO). Copolymerization decreases
the degree of crystallinity and lowers the crystallization and melting
temperatures as compared to linear PEO. The dynamics of capillary
imbibition within AAO followed the t1/2 prediction but is slower than predicted by the
classical Lucas–Washburn equation. The most prominent effect
of confinement is the change in nucleation mechanismfrom heterogeneous
nucleation in bulk to homogeneous nucleation inside AAO. The homogeneous
nucleation temperatures for the hyperbranched PEOs agree with those
of linear ones provided that the branch molecular weight is used instead
of the total molecular weight. Confinement and interfacial effects
further suppress the degree of crystallinity and speed up the segmental
dynamics.