Page 470 - Polymer-based Nanocomposites for Energy and Environmental Applications

Nanocomposite membrane for environmental remediation 423

Porous materials are considered uniform if the size distribution is narrow as opposed
to a wide pore-size distribution. The pores can be cylindrical, conical, slit-like, or
irregular in shape. They can be well organized using a vertical alignment as opposed
to a random network of tortuous pores.
Currently, many industries including food, chemical, medicine, pharmacy, bio-
technology, water, wastewater treatment, and many other fields of industries using
membrane processes are of great importance.
Artificial nonporous materials have many potential biological and medical appli-
cations including sorting, sensing, isolating, and releasing biological molecules.
Nanoporous systems engineered to mimic natural filtration systems are actively being
developed for use in smart implantable drug delivery systems, bioartificial organs, and
other novel nano-enabled medical devices. Current improvements in nanoscience
have made it conceivable to exactly control the morphology and physical and chem-
ical properties of the pores in nanoporous materials that make them progressively
attractive for controlling and recognizing transport at the molecular level.
Adiga et al. [130] developed nanoporous membranes for biomedical applications.
In in vitro and in vivo membrane applications, a few variations are presented
including biosensing, biosorting, drug delivery, and immunoisolation. Typically,
important membranes with ordered pores, various types of nanoporous materials,
and their fabrication techniques were deliberated. In implantable devices, anticipated
properties of membranes employed, comprising biocompatibility and antibiofouling
behavior, are discussed. In order to improve the function of nanoporous membranes,
the use of surface modification techniques is studied. Nevertheless, extensive research
has been carried out on fabrication, characterization, and modeling of nanoporous
materials, but there are still several trials that must be overwhelmed in order to make
synthetic nanoporous systems that work similarly to their biological counterparts.
For the filtration of viruses, nanoporous membranes with ultrahigh selectivity
and flux were developed [131]. The filtration, separation, and isolation of viruses
are serious issues associated with viral research and controlling blood-borne viral
infections [132].
For a wide variety of biomolecular analysis applications, nanoporous membranes
are also an appropriate candidate. Likely, in vitro applications comprise diagnosis and
protein separation.
Similarly, in the area of drug delivery system, nanoporous membranes with well-
controlled pore size, porosity, and membrane thickness present an effective way for
making capsules that can be employed for delivering controlled discharge of pharma-
cological agents [133].
In 2008, Yang et al. [134] introduced a suitable nanoporous membrane for virus fil-
tration using good dimensional stability under high pressures retaining high selectivity.
The membrane comprises a double layer: the upper layer is a nanoporous film having a
pore size of 17 nm and a thickness of 160 nm, which was formed by polystyrene-block-
poly(methyl methacrylate) copolymer (PS-b-PMMA) where PMMA block was
removed viaUV irradiationfollowed bywashing with acetic acid.To improvemechan-
ical strength, the nanoporous block copolymer film was associated with a traditional
microfiltration membrane. Results demonstrated that the membrane used in this