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Fabrication of Mesoporous Polystyrene Films with Controlled Porosity and Pore Size by Solvent Annealing for Templated Syntheses
journal contribution
posted on 2017-08-17, 19:37 authored by Mohan
Raj Krishnan, Yu-Cheng Chien, Chung-Fu Cheng, Rong-Ming HoHerein,
we aim to develop a facile method for the fabrication of
mesoporous polystyrene (PS) films with controlled porosity and pore
size by solvent annealing. A PS polymer film is solvent-annealed using N,N-dimethyl formamide (DMF) vapor for
the development of phase separation, followed by rapidly cooling to
the preset cryogenic temperature. Subsequently, a nonsolvent (methanol)
is introduced to extract the crystalline DMF from the DMF-swollen
PS, giving mesoporous PS with a network structure after the removal
of DMF. The porosity of the mesoporous PS films can be controlled
by the degree of swelling. Most interestingly, the phase separation
between PS and DMF at the thin-film state under solvent annealing
can be regulated by the annealing time through the spinodal decomposition,
giving the development of nanonetwork structure with controlled structural
features (i.e., framework size and interframework spacing) at invariant
porosity. Consequently, after the removal of DMF, mesoporous PS films
with controlled porosity and pore size can be obtained and then used
as a template for the fabrication of a variety of nanoporous inorganics
by templated syntheses, such as nanoporous SiO2, TiO2, and Ni, providing a cost-effective way to fabricate a range
of nanoporous materials with controlled porosity and pore size as
well as large specific surface area for aimed applications.