4 research outputs found
Interconnectivity of Macroporous Hydrogels Prepared via Graphene Oxide-Stabilized Pickering High Internal Phase Emulsions
Interconnected
macroporous polyÂ(acrylic acid) (PAA) hydrogels are
prepared via oil-in-water (o/w) Pickering high internal phase emulsion
(HIPE) templates stabilized by graphene oxide (GO). The amphiphilicity
of GO is adjusted by slight modification with cetyltrimethylammonium
bromide (CTAB). The morphology of macroporous PAA is observed by a
field-emission scanning electron microscope (FE-SEM). The gas permeability
is characterized to evaluate the interconnectivity of polymer foams.
The pore and pore throat size can be tailored by varying the wettability
and concentration of GO. The selective adsorption toward dyes of PAA
hydrogels is proved. Macroporous PAA hydrogels with an open-cell structure
show enhanced adsorption behavior of both methylene blue (MB) and
copperÂ(II) ions
Macroporous Graphene Oxide–Polymer Composite Prepared through Pickering High Internal Phase Emulsions
Macroporous polymer–graphene
oxide (GO) composites were
successfully prepared using Pickering high internal phase emulsion
(HIPE) templates. GO flakes were modified by the cationic surfactant
cetyltrimethylammonium bromide (CTAB) and used as the stabilizer of
water-in-oil (W/O) Pickering emulsions. CTAB-modified GO is effective
at stabilizing W/O Pickering HIPEs, and the lowest GO content is only
about 0.2 mg mL<sup>–1</sup> (relative to the volume of the
oil phase). The close-cell morphology of the resulting poly-Pickering
HIPEs is observed, and the void size of the porous polymers is tuned
by varying the concentration of GO. Three-dimensional macroporous
chemically modified graphene (CMG) monoliths with a high specific
surface area of about 490 m<sup>2</sup> g<sup>–1</sup> were
obtained after removing the cellular polymer substrates through calcination.
The micropores were also found in CMGs, which may be caused by the
decomposition of CTAB adsorbed on the surface of GO
Interconnected Macroporous Polymers Synthesized from Silica Particle Stabilized High Internal Phase Emulsions
<i>n</i>-Octadecyltrimethoxysilane
(ODS)-modified silica
particles were used as sole Pickering stabilizer to prepare water-in-oil
Pickering high internal phase emulsions (HIPEs) with an internal phase
volume of 80%. After polymerization of the continuous phase of HIPEs,
interconnected macroporous polymers were obtained when modified silica
was initially dispersed in water to form a micelle-like structure.
However, silica particles in oil phase resulted in closed-cell pores.
The pore size, the pore wall morphology, and the interconnectivity
of polymer foams could be adjusted finely by the grafted amounts of
ODS, modified silica concentrations, and the initial location of Pickering
stabilizer. The gas permeation of interconnected porous polymers increased
dramatically with the increase of the hydrophobicity of silica particles
from 3 to 153 mL/min
Interconnected Porous Polymers with Tunable Pore Throat Size Prepared via Pickering High Internal Phase Emulsions
Interconnected
macroporous polymers were prepared by copolymerizing
methyl acrylate (MA) via Pickering high internal phase emulsion (HIPE)
templates with modified silica particles. The pore structure of the
obtained polymer foams was observed by field-emission scanning electron
microscopy (FE-SEM). Gas permeability was characterized to evaluate
the interconnectivity of macroporous polymers. The polymerization
shrinkage of continuous phase tends to form open pores while the solid
particles surrounding the droplets act as barriers to produce closed
pores. These two conflicting factors are crucial in determining the
interconnectivity of macroporous polymers. Thus, poly-Pickering HIPEs
with high permeability and well-defined pore structure can be achieved
by tuning the MA content, the internal phase fraction, and the content
of modified silica particles