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C Hermida-Merino, M Pérez-Rodríguez, M M Piñeiro, M J Pastoriza-Gallego
The electrical conductivity of exfoliated graphite in water nanofluids has been experimentally determined, and compared with the same property when the dispersed nanosheets have been oxidized. The effect of oxidation on this property is different if compared with the case of sintered dry nanosheets. In any case, for the sintered raw material the conduction behaves as expected in a metal, while for the nanofluid it shows values and trends typical of a weak electrolyte solution. The effect of oxidation on the electrical conductivity of exfoliated graphite can be explained as being caused by the dissociation in the fluid phase of the moieties resulting from the chemical functionalization process...
April 21, 2017: Soft Matter
I M Mahbubul, Elif Begum Elcioglu, R Saidur, M A Amalina
Nanofluids are promising in many fields, including engineering and medicine. Stability deterioration may be a critical constraint for potential applications of nanofluids. Proper ultrasonication can improve the stability, and possibility of the safe use of nanofluids in different applications. In this study, stability properties of TiO2-H2O nanofluid for varying ultrasonication durations were tested. The nanofluids were prepared through two-step method; and electron microscopies, with particle size distribution and zeta potential analyses were conducted for the evaluation of their stability...
July 2017: Ultrasonics Sonochemistry
Akira Koyama, Kazuhiro Fukami, Yujin Imaoka, Atsushi Kitada, Tetsuo Sakka, Takeshi Abe, Kuniaki Murase, Masahiro Kinoshita
Manipulating the local pH within nanoconfinement is essential in nanofluidics technology and its applications. Since the conventional strategy utilizes the overlapping of an electric double layer formed for charge compensation by protons near a negatively charged pore-wall surface, pH variation within a pore is limited to the acidic side. To achieve the variation at the alkaline side, we developed a system comprising a hydrophobic pore-wall surface and aqueous solution containing hydrophobic cations. Beyond a threshold cation concentration, a nanopore is filled with the second phase where the cations are remarkably enriched due to surface-induced phase transition (SIFT) originating from the hydrophobic effect...
April 20, 2017: Physical Chemistry Chemical Physics: PCCP
Alexia Barbosa De Lima, Laurent Joly
Electro-osmosis (EO) is a powerful tool to manipulate liquids in micro and nanofluidic systems. While EO has been studied extensively at liquid-solid interfaces, the case of liquid-vapor interfaces, found e.g. in foam films and bubbles, remains to be explored. Here we perform molecular dynamics (MD) simulations of EO in a film of aqueous electrolyte covered with fluid layers of ionic surfactants and surrounded by gas. Following the experimental procedure, we compute the zeta potential from the EO velocity, defined as the velocity difference between the middle of the liquid film and the surrounding gas...
April 19, 2017: Soft Matter
Kai Huang, Igal Szleifer
Nature uses the interplay between hydrophobic and electrostatic interactions of disordered proteins to orchestrate complicated molecular gate such as the nuclear pore complex to control the transport of biological masses. Inspired by nature, we here theoretically show that well-defined gate shape, sensitive response to pH and salt concentration, and selectivity in cargo transport can be simultaneously achieved by grafting amphiphilic diblock copolymers made of sequence-controlled hydrophobic and ionizable monomers on the inner surface of solid-state nanopore...
April 19, 2017: Journal of the American Chemical Society
Si Qin, Dan Liu, Guang Wang, David Portehault, Christopher J Garvey, Yury Gogotsi, Weiwei Lei, Ying Chen
Achieving a high rate of ionic transport through porous membranes and ionic channels is important in numerous applications ranging from energy storage to water desalination, but still remains a challenge. Herein we show that ions can quickly pass through interlayer spaces in hydrated boron nitride (BN) membranes. Measurements of surface-charge governed ionic currents through BN conduits in a variety of salt solutions (KCl, NaCl and CaCl2) at low salt concentrations (<10-4 M) showed several orders of magnitude higher ionic conductivity compared to the bulk solution...
April 18, 2017: Journal of the American Chemical Society
Sangwook Lim, Darsh Wasan
Nanofluids comprising nanoparticle suspensions in liquids have significant industrial applications. Prior work performed in our laboratory on the spreading of a nanofluid on a solid substrate has revealed that the structural disjoining pressure gradient caused by the layering of the nanoparticles normal to the confining plane of the film with the wedge profile is a new mechanism for oily soil detachment from the solid substrate. In the present work, we explore the application of this new mechanism for the solid particle detachment using latex particles on glass and a copper-coated wafer substrate using nanofluids...
April 4, 2017: Journal of Colloid and Interface Science
Hongfei Cheng, Yi Zhou, Yaping Feng, Wenxiao Geng, Qinfu Liu, Wei Guo, Lei Jiang
Inspired by the microstructure of nacre, material design, and large-scale integration of artificial nanofluidic devices step into a completely new stage, termed 2D nanofluidics, in which mass and charge transportation are confined in the interstitial space between reconstructed 2D nanomaterials. However, all the existing 2D nanofluidic systems are reconstituted from homogeneous nanobuilding blocks. Herein, this paper reports the bottom-up construction of 2D nanofluidic materials with kaolinite-based Janus nanobuilding blocks, and demonstrates two types of electrokinetic energy conversion through the network of 2D nanochannels...
April 11, 2017: Advanced Materials
Rodorico Giorgi, Michele Baglioni, Piero Baglioni
One of the main problems connected to the conservation of street art is the selective removal of overlying undesired graffiti, i.e., drawings and tags. Unfortunately, selective and controlled removal of graffiti and overpaintings from street art is almost unachievable using traditional methodologies. Recently, the use of nanofluids confined in highly retentive pHEMA/PVP semi-interpenetrated polymer networks was proposed. Here, we report on the selective removal of acrylic overpaintings from a layer of acrylic paint on mortar mockups in laboratory tests...
April 10, 2017: Analytical and Bioanalytical Chemistry
L Lin, K Mawatari, K Morikawa, Y Pihosh, A Yoshizaki, T Kitamori
Single-cell analysis is of increasing importance in many fields, but is challenging due to the ultra-small volumes (picoliters) of single cells. Indeed, analysis of a specific analyte might require the analysis of a single molecule or several molecules. Analytical processes usually include sampling, chemical processing, and detection. Although several papers have reported chemical processing and detection methods for single cells, a sampling method compatible with maintaining the viability of a single cell during sampling has yet to be developed...
April 10, 2017: Analyst
Seyedeh Mahboobeh Yousefi, Farzaneh Shemirani, Sohrab Ali Ghorbanian
Novel deep eutectic solvent (DES) magnetic bucky gels (MBG) were formed by choline chloride/urea deep eutectic solvent and magnetic multi-walled carbon nanotube nanocomposite (MMWCNT) and were used in developing dispersive solid-phase extraction (dSPE) method. The hydrophilic DES based MBGs were developed with the features of magnetic susceptibility to permit fast injection of sorbent into the aqueous sample, rapid retrieval of the sorbent, high dispersion of MWCNT in water and compatibility with GC. In this work we investigated the application of DESs as a new class of carriers for CNT based nanofluids...
June 1, 2017: Talanta
Hye Jung Lee, Seoung-Jai Bai, Young Seok Song
Understanding the internal structure of composite nanofluids is critical for controlling their properties and engineering advanced composite nanofluid systems for various applications. This goal can be made possible by precise analysis with the help of a systematic robust platform. Here, we demonstrate a microfluidic device that can control the orientation of carbon nanomaterials in a suspension by applying external fields and subsequently examine the electrochemical properties of the fluids at microscale. Composite nanofluids were prepared using carbon nanomaterials, and their rheological, thermal, electrical, and morphological characteristics were examined...
April 7, 2017: Scientific Reports
Boshra Al-Absi, Suzita M Noor, Riyadh Saif-Ali, Sameer D Salem, Radwan H Ahmed, Muhammad Fm Razif, Sekaran Muniandy
Studies have shown an association between ARID5B gene polymorphisms and childhood acute lymphoblastic leukemia. However, the association between ARID5B variants and acute lymphoblastic leukemia among the Arab population still needs to be studied. The aim of this study was to investigate the association between ARID5B variants with acute lymphoblastic leukemia in Yemeni children. A total of 14 ARID5B gene single nucleotide polymorphisms (SNPs) were genotyped in 289 Yemeni children, of whom 136 had acute lymphoblastic leukemia and 153 were controls, using the nanofluidic Dynamic Array (Fluidigm 192...
April 2017: Tumour Biology: the Journal of the International Society for Oncodevelopmental Biology and Medicine
Mingwei Zhu, Yilin Wang, Shuze Zhu, Lisha Xu, Chao Jia, Jiaqi Dai, Jianwei Song, Yonggang Yao, Yanbin Wang, Yongfeng Li, Doug Henderson, Wei Luo, Heng Li, Marilyn L Minus, Teng Li, Liangbing Hu
Transparent films or substrates are ubiquitously used in photonics and optoelectronics, with glass and plastics as traditional choice of materials. Transparent films made of cellulose nanofibers are reported recently. However, all these films are isotropic in nature. This work, for the first time, reports a remarkably facile and effective approach to fabricating anisotropic transparent films directly from wood. The resulting films exhibit an array of exceptional optical and mechanical properties. The well-aligned cellulose nanofibers in natural wood are maintained during delignification, leading to an anisotropic film with high transparency (≈90% transmittance) and huge intensity ratio of transmitted light up to 350%...
March 29, 2017: Advanced Materials
Xiaoling Wu, Xin Li, Miyi Yang, Haozhe Zeng, Sanbing Zhang, Runhua Lu, Haixiang Gao, Donghui Xu
Phytophagous mites are usually considered a difficult problem for agricultural planting, and acaricides are applied to control diseases and pests. However, the overdose and misusage of acaricides causes pesticide residues. In this work, a simple and practical ionic liquid-based TiO2 nanofluid, effervescence-assisted, dispersive liquid-liquid microextraction (EA-DLLME) method was developed to detect acaricides in honey and tea by high-performance liquid chromatography (HPLC-DAD). Oleophilic TiO2 nanoparticles were synthesized by a facile solvothermal method to obtain greater stability of the nanofluid...
March 6, 2017: Journal of Chromatography. A
Xueye Chen, Shuai Zhang, Lei Zhang, Zhen Yao, Xiaodong Chen, Yue Zheng, Yanlin Liu
This review reports the progress on the recent development of electrokinetic enrichment in micro-nanofluidic chips. The governing equations of electrokinetic enrichment in micro-nanofluidic chips are given. Various enrichment applications including protein analysis, DNA analysis, bacteria analysis, viruses analysis and cell analysis are illustrated and discussed. The advantages and difficulties of each enrichment method are expatiated. This paper will provide a particularly convenient and valuable reference to those who intend to research the electrokinetic enrichment based on micro-nanofluidic chips...
September 2017: Biomedical Microdevices
Anumita Saha-Shah, Jonathan A Karty, Lane A Baker
A mobile nanofluidic device based on theta pipettes was developed for "collect-react-analyze" measurements of small volumes of a sample collected locally from biological samples. Specifically, we demonstrate execution of local reactions inside single cells and on Pseudomonas aeruginosa biofilms for targeted analysis of metabolites. Nanoliter volumes of the sample, post-reaction, were delivered to a mass spectrometer via electrospray ionization (ESI) for chemical analysis. A new strategy was developed where the additional barrel of a theta pipette was utilized both to enable chemical manipulations after sample collection and to electrospray the nanoliter sample volumes collected directly from the pipette tip...
March 31, 2017: Analyst
Amandeep Sekhon, V J Ajith, Shivprasad Patil
The flow of water confined to nanometer-sized pores is central to a wide range of subjects from biology to nanofluidic devices. Despite its importance, a clear picture about nanoscale fluid dynamics is yet to emerge. Here we measured dissipation in less than 25 nm thick water films and it was found to decrease for both wetting and non-wetting confining surfaces. The fitting of Carreau-Yasuda model of shear thinning to our measurements implies that flow is non-Newtonian and for wetting surfaces the no-slip boundary condition is largely valid...
May 24, 2017: Journal of Physics. Condensed Matter: An Institute of Physics Journal
Guang Chen, Siddhartha Das
We establish that nanochannels grafted with pH-responsive, end-charged polyelectrolyte (PE) brushes demonstrate a massive augmentation in the strength of the electroosmotic (EOS) transport in the presence of an external electric field. This contradicts the existing understanding that the EOS transport is severely retarded in channels grafted with the PE brushes due to the brush-induced enhanced drag force. Our mathematical model, developed on the basis of the fact that the ion concentration polarization (ICP) effect can be neglected, explains this enhancement of the EOS transport by noting that the end-charged PE brushes demonstrate a unique ability of localizing the electric double layer (or the EDL) or equivalently localizing the maximum charge density of the electrolyte ions at the location of its end, i...
April 4, 2017: Journal of Physical Chemistry. B
Panagiotis Kondylis, Jinsheng Zhou, Zachary D Harms, Andrew R Kneller, Lye Siang Lee, Adam Zlotnick, Stephen C Jacobson
To improve the precision of resistive-pulse measurements, we have used a focused ion beam instrument to mill nanofluidic devices with 2, 4, and 8 pores in series and compared their performance. The in-plane design facilitates the fabrication of multiple pores in series, which, in turn, permits averaging of the series of pulses generated from each translocation event. The standard deviations (σ) of the pulse amplitude distributions decrease by 2.7-fold when the average amplitudes of eight pulses are compared to the amplitudes of single pulses...
March 21, 2017: Analytical Chemistry
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