The great potential of nanoporous membranes for water filtration and chemical separation has been challenged by the trade-off between selectivity and permeability. Here we report on nanoporous ...polymer membranes with an excellent balance between selectivity and permeability of ions. Our membranes are fabricated by irradiating 2-μm-thick polyethylene terephthalate Lumirror® films with GeV heavy ions followed by ultraviolet exposure. These membranes show a high transport rate of K
ions of up to 14 mol h
m
and a selectivity of alkali metal ions over heavy metal ions of >500. Combining transport experiments and molecular dynamics simulations with a polymeric nanopore model, we demonstrate that the high permeability is attributable to the presence of nanopores with a radius of ~0.5 nm and a density of up to 5 × 10
cm
, and the selectivity is ascribed to the interaction between the partially dehydrated ions and the negatively charged nanopore wall.
Solid‐state nanopores are fascinating objects that enable the development of specific and efficient chemical and biological sensors, as well as the investigation of the physicochemical principles ...ruling the behavior of biological channels. The great variety of biological nanopores that nature provides regulates not only the most critical processes in the human body, including neuronal communication and sensory perception, but also the most important bioenergetic process on earth: photosynthesis. This makes them an exhaustless source of inspiration toward the development of more efficient, selective, and sophisticated nanopore‐based nanofluidic devices. The key point responsible for the vibrant and exciting advance of solid nanopore research in the last decade has been the simultaneous combination of advanced fabrication nanotechnologies to tailor the size, geometry, and application of novel and creative approaches to confer the nanopore surface specific functionalities and responsiveness. Here, the state of the art is described in the following critical areas: i) theory, ii) nanofabrication techniques, iii) (bio)chemical functionalization, iv) construction of nanofluidic actuators, v) nanopore (bio)sensors, and vi) commercial aspects. The plethora of potential applications once envisioned for solid‐state nanochannels is progressively and quickly materializing into new technologies that hold promise to revolutionize the everyday life.
The virtues of working with solid‐state nanopores are being increasingly recognized by the scientific community. Although in the past decades the focus has been mostly on their fundamental aspects, for several years now nanopore research has started to shift toward specific practical applications. The latest developments in this fascinating research field are brought together and summarized.
Applied nuclear physics is an essential part of the research activity at many particle accelerators. New, large accelerator facilities are currently under construction in Europe, Asia, and USA. These ...machines will be able to produce radioactive ion beams, and to increase the intensity and the energy of the heavy ions well beyond the limits currently available at the therapy or research facilities. The upcoming facilities open new opportunities for research in biomedical applications that require these special properties, such as particle radiography, radioactive beam imaging, ultra-high dose rates and new ions for therapy. Moreover, space radiation research and materials science can successfully exploit these new centers. The new facilities can pave the way to many future applications of nuclear physics for the benefit of the society. In this paper we will summarize the current status of applied sciences at high-energy accelerators, describe the characteristics of some of the machines under construction (FAIR, NICA, RAON, ELI) and discuss the new opportunities offered by these facilities in applied sciences.
Novel transport phenomena through nanopores are expected to emerge as their diameters approach subnanometer scales. However, it has been challenging to explore such a regime experimentally. Here, ...this study reports on polymer subnanometer pores exhibiting unique selective ionic transport. 12 μm long, parallel oriented polymer nanopores are fabricated in polyethylene terephthalate (PET) films by irradiation with GeV heavy ions and subsequent 3 h exposure to UV radiation. These nanopores show ionic transport selectivity spanning more than 6 orders of magnitude: the order of the transport rate is Li+>Na+>K+>Cs+>>Mg2+>Ca2+>Ba2+, and heavy metal ions such as Cd2+ and anions are blocked. The transport can be switched off with a sharp transition by decreasing the pH value of the electrolyte. Structural measurements and molecular dynamics simulations suggest that the ionic transport is attributed to negatively charged nanopores with pore radii of ≈0.3 nm, and the selectivity is associated with the dehydration effect.
Negatively charged subnanometer pores are fabricated in polymer films by GeV heavy ions irradiation without chemical etching. Their selective ionic transport rates span more than 6 orders of magnitude and follow the rarely observed Eisenman sequence XI.
Nanofluidic reverse electrodialysis systems based on track-etched nanochannels are promising devices for new eco-friendly ways of sustainable energy generation. In recent years, several works have ...been focused on the influence of parameters such as pH, ionic strength, and chemical nature of the electrolyte on the device performance. However, despite the relevance of the geometry on the channel properties, the influence of the nanochannel shape on the performance of energy conversion remains almost unexplored. In this work, we present an experimental study – complemented with Poisson–Nernst–Planck simulations – that describes how the shape of the nanochannels strongly affects the energy conversion performance of single bullet-shaped nanochannels created on PET foils by the ion-track-etching method. To test optimal parameters for energy conversion and selectivity, the performance was investigated by varying the channel effective diameter as well as the pH and the electrolyte gradient. With a maximum output power of 80 pW, this system reveals the best value reported for a bare single track-etched nanochannel. Therefore, this work experimentally demonstrates that it is possible to obtain high power output by means of a careful choice of channel geometry and etching conditions, in addition to other experimental parameters such as pH and electrolyte gradient. We believe that these results offer a promising framework to explore new design concepts in nanofluidic osmotic power generators.
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•Shape strongly affects the energy conversion performance of single nanochannels created by the ion-track-etching method.•Bullet-shaped nanochannels reach a maximum output power of 80 pW, the best value reported for bare track-etched nanochannels.•The power obtained in bullet-shaped nanochannels exceeds several values reported previously for other materials.•PNP simulations indicate that the superior performance of bullet-shaped nanochannels relies on the larger channel volumes.
The ability of living systems to respond to stimuli and process information has encouraged scientists to develop integrated nanosystems displaying similar functions and capabilities. In this regard, ...biological pores have been a source of inspiration due to their exquisite control over the transport of ions within cells, a feature that ultimately plays a major role in multiple physiological processes,
e.g.
transduction of physical stimuli into nervous signals. Developing abiotic nanopores, which respond to certain chemical, biological or physical inputs producing "iontronic" signals, is now a reality thanks to the combination of "soft" surface science with nanofabrication techniques. The interplay between the functional richness of predesigned molecular components and the remarkable physical characteristics of nanopores plays a critical role in the rational integration of molecular functions into nanopore environments, permitting us to envisage nanopore-based biomimetic integrated nanosystems that respond to a variety of external stimuli such as pH, redox potential, molecule concentration, temperature, or light. Transduction of these stimuli into a predefined "
iontronic
" response can be amplified by exploiting nanoconfinement and physico-chemical effects such as charge distribution, steric constraints, equilibria displacement, or local changes in ionic concentration, to name but a few examples. While in past decades the focus has been mostly on their fundamental aspects and the in-depth study of their interesting transport properties, for several years now nanopore research has started to shift towards specific practical applications. This work is dedicated to bringing together the latest developments in the use of nanopores as "
iontronic
" transducing elements. Our aim is to show the wide potential of abiotic nanopores in sensing and signal transduction and also to promote the potential of this technology among doctoral students, postdocs, and researchers. We believe that even a casual reader of this perspective will not fail to be impressed by the wealth of opportunities that solid-state nanopores can offer to the transduction of biological, physical and chemical stimuli.
Here, we show the wide potential of abiotic nanopores in sensing and signal transduction and also to promote the potential of this technology among doctoral students, postdocs, and researchers.
A major challenge to understanding the response of materials to extreme environments (e.g., nuclear fuels/waste forms and fusion materials) is to unravel the processes by which a material can ...incorporate atomic-scale disorder, and at the same time, remain crystalline. While it has long been known that all condensed matter, even liquids and glasses, possess short-range order, the relation between fully-ordered, disordered, and aperiodic structures over multiple length scales is not well understood. For example, when defects are introduced (via pressure or irradiation) into materials adopting the pyrochlore structure, these complex oxides either disorder over specific crystallographic sites, remaining crystalline, or become aperiodic. Here we present neutron total scattering results characterizing the irradiation response of two pyrochlores, one that is known to disorder (Er2Sn2O7) and the other to amorphize (Dy2Sn2O7) under ion irradiation. The results demonstrate that in both cases, the local pyrochlore structure is transformed into similar short range configurations that are best fit by the orthorhombic weberite structure, even though the two compositions have distinctly different structures, aperiodic vs. disordered-crystalline, at longer length scales. Thus, a material's resistance to amorphization may not depend primarily on local defect formation energies, but rather on the structure's compatibility with meso-scale modulations of the local order in a way that maintains long-range periodicity.
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The design of an all‐plastic field‐effect nanofluidic diode is proposed, which allows precise nanofluidic operations to be performed. The fabrication process involves the chemical synthesis of a ...conductive poly(3,4‐ethylenedioxythiophene) (PEDOT) layer over a previously fabricated solid‐state nanopore. The conducting layer acts as gate electrode by changing its electrochemical state upon the application of different voltages, ultimately changing the surface charge of the nanopore. A PEDOT‐based nanopore is able to discriminate the ionic species passing through it in a quantitative and qualitative manner, as PEDOT nanopores display three well‐defined voltage‐controlled transport regimes: cation‐rectifying, non‐rectifying, and anion rectifying regimes. This work illustrates the potential and versatility of PEDOT as a key enabler to achieve electrochemically addressable solid‐state nanopores. The synergism arising from the combination of highly functional conducting polymers and the remarkable physical characteristics of asymmetric nanopores is believed to offer a promising framework to explore new design concepts in nanofluidic devices.
The integration of conductive poly(3,4‐ethylenedioxythiophene) (PEDOT) into asymmetric solid‐state nanopores leads the way to the construction of all‐plastic field‐effect nanofluidic diodes. The conducting layer acts as a gate electrode by changing its electrochemical state upon the application of different voltages. PEDOT‐based electrochemically addressable nanofluidic devices display three well‐defined voltage‐controlled transport regimes: cation‐rectifying, nonrectifying, and anion rectifying regimes.
Grain size effects on irradiated CeO2, ThO2, and UO2 Cureton, William F.; Palomares, Raul I.; Walters, Jeffrey ...
Acta materialia,
November 2018, 2018-11-00, 2018-11, 2018-11-01, Letnik:
160, Številka:
C
Journal Article
Recenzirano
Odprti dostop
Microcrystalline and nanocrystalline UO2, ThO2, and CeO2 (∼2 μm and∼20 nm particle size, respectively) were irradiated with 946 MeV Au ions at room temperature and characterized by synchrotron X-ray ...diffraction, Raman spectroscopy, and transmission electron microscopy. All samples show a small increase in unit cell parameter as a function of ion fluence (0.17 ± 0.03% for CeO2 and 0.11 ± 0.03% for ThO2), except microcrystalline UO2, which displays a small contraction of the unit cell (−0.06 ± 0.02%). Raman spectroscopy measurements of microcrystalline UO2 indicate an increase in nonstoichiometry after irradiation. All bulk materials are subject to an increase in heterogeneous microstrain, most notably UO2, implying that the relatively small changes in unit cell parameter are accompanied by substantial local disorder induced by isolated defects. The magnitude of volumetric swelling for all materials is larger in the nanocrystalline form as compared with the microcrystalline form (0.38 ± 0.60% for CeO2, 0.14 ± 0.03% for ThO2, and 0.52 ± 0.13% for UO2). ThO2 shows the smallest difference in swelling between the microcrystalline and nanocrystalline samples (∼0.03%). All nanocrystalline materials exhibit irradiation-induced grain coarsening along with a decrease in heterogeneous microstrain with increasing ion fluence, except nanocrystalline CeO2, which shows no observable change in grain size and a slight increase in heterogeneous microstrain attributed to the accelerated formation of a secondary Ce11O20 phase evidenced in the X-ray diffraction data, present in both nanocrystalline and microcrystalline materials. Surprisingly, nanocrystalline UO2 exhibits a significant degree of swelling indicative of a decrease in oxygen content along with an increase in disorder induced by oxygen loss at grain boundaries during irradiation, based on the analysis of X-ray diffraction and Raman spectroscopy.
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Review of A2B2O7 pyrochlore response to irradiation and pressure Lang, Maik; Zhang, Fuxiang; Zhang, Jiaming ...
Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms,
10/2010, Letnik:
268, Številka:
19
Journal Article
Recenzirano
This article reviews recent research on swift heavy-ion irradiations and high-pressure studies on pyrochlores of the Gd2Zr2a x Ti x O7 binary . Applying three complementary analytical techniques ...(synchrotron X-ray diffraction, Raman spectroscopy and transmission electron microscopy) allowed for the investigation of the response of pyrochlore to irradiation and/or pressure. The chemical composition of pyrochlore has a strong effect on the character and energetics of the type of structural modifications that can be obtained under pressure or irradiation: For Ti-rich pyrochlores, the crystalline-to-amorphous transition is the dominant process. When Zr is substituted for Ti, an order-disorder transformation to the defect-fluorite structure becomes the increasingly dominant process. Except for Gd2Zr2O7, single ion tracks in pyrochlore consist of an amorphous core, surrounded by a crystalline, but disordered, defect-fluorite shell. This shell is surrounded by a defect-rich pyrochlore region. In contrast to similar effects observed when pressure or irradiation are applied separately, the response of the pyrochlore structure is significantly different when it is exposed simultaneously to pressure and irradiation. The combination of relativistic heavy ions with high pressure results in the formation of a new metastable pyrochlore phase. TEM and quantum-mechanical calculations suggest that these novel structural modifications are caused by the formation of nanocrystals and the modified energetics of nanomaterials.
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