Just Squeeze In — Drexel Researchers Discover When Spaces Are Tight, Nature Loosens Its Laws
It turns out that when they’re in a hurry and space is limited, ions, like people, will find a way to cram in — even if that means defying nature’s norms. Recently published research from an international team of scientists, including Drexel University’s Yury Gogotsi, PhD, shows that the charged particles will actually forgo their “opposites attract” behavior, called Coulombic ordering, when confined in the tiny pores of a nanomaterial. This discovery could be a pivotal development for energy storage, water treatment and alternative energy production technologies, which all involve ions packing into nanoporous materials.
In their paper, which was recently published in the journal Nature Materials, the researchers explain how Coulombic ordering in liquid salts starts to break down when ions are confined in small spaces — specifically carbon pores less than a nanometer in diameter. And the narrower the pore, the less the ions adhere to Coulombic ordering.
“This is the first time breaking of the Coulombic ordering in subnanometer pores has been convincingly demonstrated,” said Gogotsi, an author of the paper, who is the Distinguished University and Bach professor in Drexel’s College of Engineering. “The breaking of symmetry principals, like Coulombic ordering, plays an essential role in nature. But many of these processes occur without us understanding them and knowing their mechanisms. Science can reveal those hidden processes. And if we understand them, we can eventually develop better technology by working at the same nanometer and subnanometer scales that nature does.”
To make its discovery, the team — including researchers from Shinshu University in Japan; Loughborough University in the United Kingdom; The University of Adelaide in Australia; and Sorbonne University, the French Research Network on Electrochemical Energy Storage, and Paul Sabatier University in France — created two sets of carbon nanomaterials. One had pores at least a nanometer in diameter and one with pores less than a nanometer. They then used the materials to draw in ionic liquid as if they were a sponge sopping up water.
In ionic liquids, which are room-temperature liquid salts often used as solvents in the chemical industry, ions are layered in full compliance with the alternating positive-negative pattern of Coulombic ordering. But as the ionic liquid drew into the carbon nanopores it forced the ions to line up in single- and double-file lines. And, like a flock of elementary schoolers running for the bus, they didn’t always end up in line next to their usual cohorts.
“In this state, the Coulombic ordering of the liquid is broken,” the authors wrote. “Ions of the same charge neighbor each other due to a screening of their electrostatic interactions by the image charges induced in the pore walls.”
The team observed this disruption in the natural order of ions through x-ray scattering and modeled the process to explain the experimental observations. They also reported that the non-Coulombic ordering became more pronounced when an electric charge was applied to the carbon material.
“Our results suggest the existence of a molecular-scale mechanism that reduces the Coulombic repulsion energy between co-ions that become closer to each other,” they wrote. This mechanism, they theorize, is linked to the charge temporarily imposed on the walls of the carbon pores. This “image charge,” they write, offsets the natural electrostatic repulsion of ions of the same charge, to allow the channels to fill with same-charged ions lined up next to each other.
Gogotsi suggests this discovery could make it more feasible to use ionic liquids in batteries and other energy storage devices, which has been examined as a method for making batteries safer but has yet to catch on because it limits their performance.
“We can get safer batteries and supercapacitors when using ionic liquid electrolytes because they are not flammable like the electrolyte solution currently used in these devices,” Gogotsi said. “Also, since there is no solvent, the entire volume is occupied by ions and we may be able to store more energy compared to conventional electrolytes that use organic solvents.”
He’s also looking at this discovery as one that could have a significant impact on the push for water desalination technology. Membranes currently being developed to turn salt water into drinking water could be improved with this knowledge about ion behavior within subnanometer pores.
“This work adds fundamental understanding to how different things can behave below one nanometer in scale,” Gogotsi said. “We go beyond nanotechnology and into sub-nanoscale process — that’s the next frontier.”
Source: http://drexel.edu/now/archive/2017/September/nanopore-non-Coulombic-ordering/
Congratulations and thank you to our collaborators from TU Wien and CEST for very interesting work and making it published! In this work, an upscalable electrochemical MXene synthesis is presented. Yields of up to 60% electrochemical MXene (EC-MXene) with no byproducts from a single exfoliation cycle are achieved.
Thank you to our collaborators for the amazing joint work recently published in Graphene and 2D Nanomaterials about MXene–silk fibroin composite films aiming to develop materials with tunable electronic and thermal properties
Congratulations to all collaborators with this interesting joint work!
Dr. Oleksiy Gogotsi, director of MRC and Carbon-Ukraine, innovative companies that are among the leaders on the world MXene market, visited 2024 MRS Fall Meeting & Exhibit. together with Dr. Maksym Pogorielov, Head of Advanced Biomaterials and Biophysics Laboratory, University of Latvia.
MRC and Carbon-Ukraine team visited the 3rd International MXene conference held at Drexel University on August 5-8, 2024. Conference brought together the best reserchers and leading experts on MXene field. 
Together with colleagues from the University of Latvia, MRC/Carbone Ukraine, Adam Mickiewicz University, University Clinic Essen, and others, we have developed a novel concept involving the binding of antibodies to MXenes. In our research, we utilized anti-CEACAM1 antibodies to develop targeted photo-thermal therapy for melanoma (in vitro), paving the way for future in vivo studies and clinical trials. For the first time, we demonstrate the feasibility of delivering MXenes specifically targeted to melanoma cells, enabling the effective ablation of cancer cells under near-infrared (NIR) light. This new technique opens up vast potential for the application of MXenes in cancer treatment, diagnostics, drug delivery, and many other medical purposes.
Here we demonstrate a new developed method for depositing Ti3C2Tx MXenes onto hydrophobic electrospun PCL membranes using oxygen plasma treatment. These novel patches hold tremendous potential for providing mechanical support to damaged heart tissue and enabling electrical signal transmission,thereby mimicking the crucial electroconductivity required for normal cardiac function. After a detailed investigation of scaffold-to-cell interplay, including electrical stimulation, novel technology has the potential for clinical application not only for cardiac regeneration, but also as neural and muscular tissue substitutes.
MX-MAP project participants from MRC Dr. Oleksiy Gogotsi and Veronika Zahorodna performed split secondment visit to project partner organization University of Padova (Italy). MX-MAP project works on development of the key strategies for MXene medical applications. 
CanbioSe Project Meeting and Project Workshop was held at European Institute of Membranes (IEM), University of Montpellier, France on September 26-27, 2023. The workshop was focused on the theme of "Commercializing Biosensors, Intellectual Property, and Knowledge Transfer from Academia to Industry.
Dr. Oleksiy Gogotsi and Veronika Zahorodna visited IEEE NAP 2023 conference held in Bratislava on September 10-15, 2023. The prime focus of the IEEE NAP-2023 was on nanoscale materials with emphasis on interdisciplinary research exploring and exploiting their unique physical and chemical proprieties for practical applications.
Director of MRC and Carbon-Ukraine Dr. Oleksiy Gogotsi visited CEST labs in Wiener Neustadt (Low Energy Ion Scattering, Batteries development) and TU Vienna (ELSA, SFA). He meet with Dr. Pierluigi Bilotto, Dr. Chriatian Pichler and their colleagues, discussing novel materials and r&d activities for new technologies.