Unique Liquid Properties Research Articles

Quantitative characterization of liquids flowing in geometrically controlled sub-100nm nanofluidic channels.

With development of nanotechnologies, applications exploiting nanospaces such as single-molecule analysis and high-efficiency separation have been reported, and understanding properties of fluid flows in 101nm to 102nm scale spaces becomes important. Nanofluidics has provided a platform of nanochannels with defined size and geometry, and revealed various unique liquid properties including higher water viscosity with dominant surface effects in 102nm spaces. However, experimental investigation of fluid flows in 101nm spaces is still difficult owing to lack of fabrication procedure for 101nm nanochannels with smooth walls and precisely controlled geometry. In the present study, we established a top-down fabrication process to realize fused-silica nanochannels with 101nm scale size, 100nm roughness and rectangular cross-sectional shape with an aspect ratio of 1. Utilizing a method of mass flowmetry developed by our group, accurate measurements of ultra-low flow rates in sub-100nm nanochannels with sizes of 70nm and 100nm were demonstrated. The results suggested that the viscosity of water in these sub-100nm nanochannels was approximately 5 times higher than that in the bulk, while that of dimethyl sulfoxide was similar to the bulk value. The obtained liquid permeability in the nanochannels can be explained by a hypothesis of loosely structured liquid phase near the wall generated by interactions between the surface silanol groups and protic solvent molecules. The present results suggest the importance of considering the species of solvent, the surface chemical groups, and the size and geometry of nanospaces when designing nanofluidic devices and membranes.

Improvement of cleaning parameters of pipeline elements based on simulation of movement of solid magnetite particles in electrically conductive liquid

The unique properties of liquids that can interact with electric and magnetic fields are used in mechanical engineering, technology and medicine. The possibility of the influence of the magnetic field on the solid particles of the liquid in the pipeline allows cleaning of the solid walls of the pipeline, which is the object of the study. Magnetic liquids are solutions of ferromagnets in a liquid, and their physical properties in a magnetic field cause structural transformations in such liquids. The treatment of electrically conductive liquids in a magnetic field and their use for cleaning water from oil or oil residues are considered. On the basis of numerical modeling, the movement of solid particles of magnetite, which is part of an electrically conductive liquid, was investigated by jointly solving the equations of Reynolds, Maxwell, non-discontinuity and the turbulence model. The physical phenomena of the movement of solid particles of magnetite-based conductive liquid in various elements of the pipeline were determined, which improved the parameters of cleaning liquids contaminated with oil and oil. The magnetic particles of the electrically conductive liquid quite nicely fill the boundaries of the intersection if there is a flow reversal, as it happens in radiators. An increase in the intensity of the magnetic field leads to a change in the velocity profile of the conductive liquid, which prevents magnetite particles from penetrating close to the wall. An increase in the power of the magnetic field makes it possible to detach the contamination from the walls of the pipeline together with the solid particle of magnetite. A 73 % increase in wear in certain sections of the pipeline is due to the effect of the centrifugal force acting on the particle during rotation. The sudden expansion of the flow makes it difficult for particles to reach the pipe surfaces, which worsens the cleaning conditions. The number of particles on the surface is 82 % less compared to the absence of sudden expansion

Liquid-Based Memory Devices for Next-Generation Computing

Liquid-based devices have emerged as bioinspired neuromorphic applications owing to their high ion-diffusion coefficients, diverse structures, and controllable ion-exchange reactions. By engineering and modifying liquid materials, multifunctional liquid-based computing devices have been developed for next-generation memory and neuromorphic devices. The unique properties of liquids make them feasible for memory functions and various synaptic applications, such as emulating synaptic plasticity, homeostasis, and action potentials. Utilizing liquids in computing devices provides a promising and versatile platform for high-performance memory devices and enables the emulation of bioinspired computing functions. In this Spotlight, we highlight recent advances in liquid-based memory devices and focus on synaptic applications. We then discuss possible array structures and scaling-down technologies for liquid-based devices. Finally, the challenges and future prospects of liquid-based devices are discussed.

Fabrication of Infrared-Compatible Nanofluidic Devices for Plasmon-Enhanced Infrared Absorption Spectroscopy

Nanofluidic devices have offered us fascinating analytical platforms for chemical and bioanalysis by exploiting unique properties of liquids and molecules confined in nanospaces. The increasing interests in nanofluidic analytical devices have triggered the development of new robust and sensitive detection techniques, especially label-free ones. IR absorption spectroscopy is one of the most powerful biochemical analysis methods for identification and quantitative measurement of chemical species in the label-free and non-invasive fashion. However, the low sensitivity and the difficulties in fabrication of IR-compatible nanofluidic devices are major obstacles that restrict the applications of IR spectroscopy in nanofluidics. Here, we realized the bonding of CaF2 and SiO2 at room temperature and demonstrated an IR-compatible nanofluidic device that allowed the IR spectroscopy in a wide range of mid-IR regime. We also performed the integration of metal-insulator-metal perfect absorber metamaterials into nanofluidic devices for plasmon-enhanced infrared absorption spectroscopy with ultrahigh sensitivity. This study also shows a proof-of-concept of the multi-band absorber by combining different types of nanostructures. The results indicate the potential of implementing metamaterials in tracking several characteristic molecular vibrational modes simultaneously, making it possible to identify molecular species in mixture or complex biological entities.

An Optimized DTW Algorithm Using the RMSE Approach to Classify the Liquids in Ka-Band

ABSTRACT In this paper, a new optimized algorithm is presented to classify the liquids with high-level accuracy using raw data which show the transmission parameter of liquids. The free space measurement method, one of the microwave spectroscopy methods, has been chosen to collect the parameter for use in detecting illegal and explosive liquids. The aim is to classify the liquids that the passenger can choose with his/her plane journey. To classify and identify these liquids, instead of a multivariate data analysis method, a simpler dynamic time warping algorithm method is proposed. It is advantageous to intervene in this algorithm to perform the classification process better. It will be able to determine the most contradictory similarities among the signals collected from liquids and perform the best classification process. Thanks to this feature, it is expected to give better results than the algorithms proposed earlier. Because, it is thought that the liquids can be classified by the parameter which has unique properties of liquids. Furthermore, this algorithm will allow an intermediate group of suspicious liquids to be detected in another group. The performance of the proposed model is discussed in terms of its potential for reducing the classification problem and composing a database which can be used to identify the un/known materials easily.

Extended-Nanofluidic Devices and the Unique Liquid Properties - Invited Paper

Microfluidic devices are downscaling to 10-100 nm space, which we call extended-nano space. Because the extended-nano space is a space to bridge isolated molecules and normal bulk fluid, new solution chemistry can be expected. However, it was difficult to investigate due to the ultra-small space. Our group developed fundamental technologies for the extended-nano fluidics such as nanofabrication and bonding for glass substrates, aL-fL pressure driven fluidic control, partial surface modification, and single molecule detection. Based on these technologies, many unique liquid properties were found such as viscosity increase, enhanced proton mobility, lower dielectric constant. In addition, the liquid property changes depended on channel size, channel shape, and kinds of liquid. New analytical and energy devices are created utilizing the unique properties in the extended-nano space. In this talk, fundamental technologies and unique liquid properties found in this space are mainly presented, which would have impact not only on chemistry and biology but also on semiconductor industry.

An Integrated Glass Nanofluidic Device Enabling In-situ Electrokinetic Probing of Water Confined in a Single Nanochannel under Pressure-Driven Flow Conditions.

In-situ measurement of streaming currents in a single nanochannel with femtoliter-scale volumes is achieved using an elaborately designed and fabricated glass nanofluidic chip with probe electrodes embedded within the nanochannel. The device and the method suggest a useful nanoscale tool enabling in situ understanding of the unique liquid properties observed in nanofluidic channels.

Extended-Nanofluidics: Fundamental Technologies, Unique Liquid Properties, and Application in Chemical and Bio Analysis Methods and Devices

Engineering using liquids confined in channels 10-1000 nm in dimension, or "extended-nanofluidics," is the next target of microfluidic science. Liquid properties at this scale were unrevealed until recently because of the lack of fundamental technologies for investigating these ultrasmall spaces. In this article, the fundamental technologies are reviewed, and the emerging science and technology in the extended-nanospace are discussed.

Extended nanospace chemical systems on a chip for new analytical technology

Integration of chemical processes on a microchemical chip has gained much attention in the past decade, and the basic concepts of micro-integration and the supporting technologies have been intensively developed. As a result, many analytical and chemical synthesis applications were demonstrated. The superior performances were verified including shortening analysis time, decrease of sample and reagent volume, and easy chemical operations. Now, the micro-technologies are moving toward practical applications by establishing the systems in which the microchemical chip works as chemical central processing unit. Recently, as a new research field, integration is further proceeding to the 10(1)-10(3) nm scale, which we call extended nanospace. The extended nanospace locates the gap between the targets of conventional nanotechnology (10(0)-10(1) nm) and micro-technology (>1 μm), and the fluidics and chemistry have not been explored well due to a lack of fundamental technologies. For these purposes, many methodologies were established in recent years. Unique liquid properties were reported, which were quite different from those in microspace. Some properties can be expected by considering the characteristics of microspace and the downscaling, and the others are unexpected or are difficult to predict. These properties enabled new chemical operations which will be quite important as the next analytical technologies. Now, chemistry and fluidics in the extended nanospace are forming a new research field. In this review, we survey the fundamental technologies for extended nanospace researches and introduce several unique liquid properties. Finally, unique chemical operations are also illustrated leading to new analytical operations.