To the naked eye, both water molecules and germs are invisible -- objects so tiny they are measured by the nanometer, a unit of length about 100,000 times thinner than the width of a human hair.
But at the microscopic level, the two actually differ greatly in size. A single water molecule is less than a nanometer wide, while some of the most diminutive bacteria are a couple hundred.
Working with a special kind of polymer called a block copolymer, a UB research team has synthesized a new kind of nanomembrane containing pores about 55 nanometers in diameter -- large enough for water to slip through easily, but too small for bacteria.
The pore size is the largest anyone has achieved to date using block copolymers, which possess special properties that ensure pores will be evenly spaced, said Javid Rzayev, the UB chemist who led the study. The findings were published online on Jan. 31 in Nano Letters and will appear in the journal's print edition later this year, with UB chemistry graduate student Justin Bolton as lead author.
"These materials present new opportunities for use as filtration membranes," said Rzayev, an assistant professor of chemistry. "Commercial membranes have limitations as far as pore density or uniformity of the pore size. The membranes prepared from block copolymers have a very dense distribution of pores, and the pores are uniform."
"There's a lot of research in this area, but what our research team was able to accomplish is to expand the range of available pores to 50 nanometers in diameter, which was previously unattainable by block-copolymer-based methods," Rzayev continued. "Making pores bigger increases the flow of water, which will translate into cost and time savings. At the same time, 50 to 100 nm diameter pores are small enough not to allow any bacteria through. So, that is a sweet spot for this kind of application."
The new nanomembrane owes its special qualities to the polymers that scientists used to create it. Block copolymers are made up of two polymers that repel one another but are "stitched" together at one end to form the single copolymer.
When many block copolymers are mixed together, their mutual repulsion leads them to assemble in a regular, alternating pattern. The result of that process, called self-assembly, is a solid nanomembrane comprising two different kinds of polymers.
To create evenly spaced pores in the material, Rzayev and colleagues simply removed one of the polymers. The pores' relatively large size was due to the unique architecture of the original block copolymers, which were made from bottle-brush molecules that resemble round hair brushes, with molecular "bristles" protruding all the way around a molecular backbone.
The research on nanomembranes is part of a larger suite of studies Rzayev is conducting on bottle-brush molecules using a National Science Foundation CAREER award, the foundation's most prestigious award for junior investigators. His other work includes the fabrication of organic nanotubes for drug delivery, and the assembly of layered, bottle-brush polymers that reflect visible light like the wings of a butterfly do.
The University at Buffalo is a premier research-intensive public university, a flagship institution in the State University of New York system and its largest and most comprehensive campus. UB's more than 28,000 students pursue their academic interests through more than 300 undergraduate, graduate and professional degree programs. Founded in 1846, the University at Buffalo is a member of the Association of American Universities.
Charlotte Hsu | EurekAlert!
Scientists uncover the role of a protein in production & survival of myelin-forming cells
19.07.2018 | Advanced Science Research Center, GC/CUNY
NYSCF researchers develop novel bioengineering technique for personalized bone grafts
18.07.2018 | New York Stem Cell Foundation
A new manufacturing technique uses a process similar to newspaper printing to form smoother and more flexible metals for making ultrafast electronic devices.
The low-cost process, developed by Purdue University researchers, combines tools already used in industry for manufacturing metals on a large scale, but uses...
For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.
To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...
For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.
Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...
Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.
A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...
Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.
"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....
13.07.2018 | Event News
12.07.2018 | Event News
03.07.2018 | Event News
20.07.2018 | Power and Electrical Engineering
20.07.2018 | Information Technology
20.07.2018 | Materials Sciences