Browse
Submit Data
Databases
API
Help

Dataset Information

0 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

The Self-Propulsion of the Spherical Pt–SiO2 Janus Micro-Motor

ABSTRACT: The double-faced Janus micro-motor, which utilizes the heterogeneity between its two hemispheres to generate self-propulsion, has shown great potential in water cleaning, drug delivery in micro/nanofluidics, and provision of power for a novel micro-robot. In this paper, we focus on the self-propulsion of a platinum–silica (Pt–SiO2) spherical Janus micro-motor (JM), which is one of the simplest micro-motors, suspended in a hydrogen peroxide solution (H2O2). Due to the catalytic decomposition of H2O2 on the Pt side, the JM is propelled by the established concentration gradient known as diffusoiphoretic motion. Furthermore, as the JM size increases to O (10 ?m), oxygen molecules nucleate on the Pt surface, forming microbubbles. In this case, a fast bubble propulsion is realized by the microbubble cavitation-induced jet flow. We systematically review the results of the above two distinct mechanisms: self-diffusiophoresis and microbubble propulsion. Their typical behaviors are demonstrated, based mainly on experimental observations. The theoretical description and the numerical approach are also introduced. We show that this tiny motor, though it has a very simple structure, relies on sophisticated physical principles and can be used to fulfill many novel functions.

SUBMITTER: Zhang J

PROVIDER: S-EPMC6189969 | biostudies-literature | 2017 Apr

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Similar Datasets

Hydrophobic Janus Foam Motors: Self-Propulsion and On-The-Fly Oil Absorption.

Project description:In this work, we for the first time have proposed and fabricated a self-propelled Janus foam motor for on-the-fly oil absorption on water by simply loading camphor/stearic acid (SA) mixture as fuels into one end of the SA-modified polyvinyl alcohol (PVA) foam. The as-fabricated Janus foam motors show an efficient Marangoni effect-based self-propulsion on water for a long lifetime due to the effective inhibition of the rapid release of camphor by the hydrophobic SA in the fuel mixture. Furthermore, they can automatically search, capture, and absorb oil droplets on the fly, and then be spontaneously self-assembled after oil absorption due to the self-propulsion of the motors as well as the attractive capillary interactions between the motors and oil droplets. This facilitates the subsequent collection of the motors from water after the treatment. Since the as-developed Janus foam motors can effectively integrate intriguing behaviors of the self-propulsion, efficient oil capture, and spontaneous self-assembly, they hold great promise for practical applications in water treatment.

| S-EPMC6187715 | biostudies-literature

Dye-Enhanced Self-Electrophoretic Propulsion of Light-Driven TiO<sub>2</sub>-Au Janus Micromotors.

Project description:Light-driven synthetic micro-/nanomotors have attracted considerable attention in recent years due to their unique performances and potential applications. We herein demonstrate the dye-enhanced self-electrophoretic propulsion of light-driven TiO2-Au Janus micromotors in aqueous dye solutions. Compared to the velocities of these micromotors in pure water, 1.7, 1.5, and 1.4 times accelerated motions were observed for them in aqueous solutions of methyl blue (10-5 g L-1), cresol red (10-4 g L-1), and methyl orange (10-4 g L-1), respectively. We determined that the micromotor speed changes depending on the type of dyes, due to variations in their photodegradation rates. In addition, following the deposition of a paramagnetic Ni layer between the Au and TiO2 layers, the micromotor can be precisely navigated under an external magnetic field. Such magnetic micromotors not only facilitate the recycling of micromotors, but also allow reusability in the context of dye detection and degradation. In general, such photocatalytic micro-/nanomotors provide considerable potential for the rapid detection and "on-the-fly" degradation of dye pollutants in aqueous environments.

| S-EPMC6199027 | biostudies-literature

Gravitaxis in spherical Janus swimming devices.

Project description:In this work, we show that the asymmetrical distribution of mass at the surface of catalytic Janus swimmers results in the devices preferentially propelling themselves upward in a gravitational field. We demonstrate the existence of this gravitaxis phenomenon by observing the trajectories of fueled Janus swimmers, which generate thrust along a vector pointing away from their metallically coated half. We report that as the size of the spherical swimmer increases, the propulsive trajectories are no longer isotropic with respect to gravity, and they start to show a pronounced tendency to move in an upward direction. We suggest that this effect is due to the platinum caps asymmetric mass exerting an increasing influence on the azimuthal angle of the Janus sphere with size, biasing its orientation toward a configuration where the heavier propulsion generating surface faces down. This argument is supported by the good agreement we find between the experimentally observed azimuthal angle distribution for the Janus swimmers and predictions made by simple Boltzmann statistics. This gravitaxis phenomenon provides a mechanism to autonomously control and direct the motion of catalytic swimming devices and so enable a route to make autonomous transport devices and develop new separation, sensing, and controlled release applications.

| S-EPMC3901380 | biostudies-literature

Bias-polarity-dependent resistance switching in W/SiO2/Pt and W/SiO2/Si/Pt structures.

Project description:SiO2 is the most significantly used insulator layer in semiconductor devices. Its functionality was recently extended to resistance switching random access memory, where the defective SiO2 played an active role as the resistance switching (RS) layer. In this report, the bias-polarity-dependent RS behaviours in the top electrode W-sputtered SiO2-bottom electrode Pt (W/SiO2/Pt) structure were examined based on the current-voltage (I-V) sweep. When the memory cell was electroformed with a negative bias applied to the W electrode, the memory cell showed a typical electronic switching mechanism with a resistance ratio of ~100 and high reliability. For electroforming with opposite bias polarity, typical ionic-defect-mediated (conducting filament) RS was observed with lower reliability. Such distinctive RS mechanisms depending on the electroforming-bias polarity could be further confirmed using the light illumination study. Devices with similar electrode structures with a thin intervening Si layer between the SiO2 and Pt electrode, to improve the RS film morphology (root-mean-squared roughness of ~1.7 nm), were also fabricated. Their RS performances were almost identical to that of the single-layer SiO2 sample with very high roughness (root-mean-squared roughness of ~10 nm), suggesting that the reported RS behaviours were inherent to the material property.

| S-EPMC4768181 | biostudies-other

Directed propulsion of spherical particles along three dimensional helical trajectories.

Project description:Active colloids are a class of microparticles that 'swim' through fluids by breaking the symmetry of the force distribution on their surfaces. Our ability to direct these particles along complex trajectories in three-dimensional (3D) space requires strategies to encode the desired forces and torques at the single particle level. Here, we show that spherical colloids with metal patches of low symmetry self-propel along non-linear 3D trajectories when powered remotely by an alternating current (AC) electric field. In particular, particles with triangular patches of approximate mirror symmetry trace helical paths along the axis of the field. We demonstrate that the speed and shape of the particle's trajectory can be tuned by the applied field strength and the patch geometry. We show that helical motion can enhance particle transport through porous materials with implications for the design of microrobots that can navigate complex environments.

| S-EPMC6561940 | biostudies-literature

Compatibilization Behavior of Double Spherical TETA-SiO2@PDVB Janus Particles Anchored at the Phase Interface of Acrylic Resin/Epoxy Resin (AR/EP) Polymer Blends.

Project description:The inorganic particles used as a compatibilizer play a role in crack termination and heat resistance. However, the poor compatibility of inorganic particles and polymer hinders their application. Herein, the double spherical SiO2@PDVB Janus particles (JPs) were modified with triethylenetetramine (TETA), and the obtained anisotropic TETA-SiO2@PDVB JPs were used as the compatibilizer of acrylic resin/epoxy resin (AR/EP) composites. The modification and the compatibilization of TETA-SiO2@PDVB JPs were studied by scanning electron microscopy, X-ray photoelectron spectroscopy, differential scanning calorimetry, and dynamic mechanical analyzer, impact test, tensile test, and so forth. Results show that amino groups grafted onto the SiO2 lobe can react with epoxy groups of EP, which results in the TETA-SiO2 lobe being embedded in the EP phase and the PDVB lobe being pushed toward the AR phase. The TETA-SiO2@PDVB JPs anchored at the interface of AR and EP increase their interfacial adhesion, decrease the domain phase size and distribution of dispersed AR, and improve the compatibility of AR/EP composites. The compatibilization of nanoparticles (NPs) is realized by the cavitation and blunting of different scaled AR phase domain distributions and that of JPs is realized by the strong interfacial force originated by JPs. Moreover, the desorption energy of TETA-SiO2@PDVB JPs is higher than that of SiO2-TETA; so the glass transition temperature (T g) of AR/EP/JP composites is higher than that of AR/EP/NP composites. The strong interfacial adhesion and high desorption energy endow TETA-SiO2@PDVB JPs with a toughening effect and enhancing effect. The impact strength and the tensile strength of AR/EP/TETA-SiO2@PDVB composites are 16.03 kJ/m2 and 63.12 MPa, which are 9.91 kJ/m2 and 16.32 MPa higher than those of AR/EP composites, respectively. JPs used in the thermosetting EP is benefit to its toughening study and the new anisotropic Janus compatibilizer.

| S-EPMC6822127 | biostudies-literature

Micro-gun based on laser pulse propulsion.

Project description:This paper proposes a novel "micro-gun" structure for laser pulse propulsion. The "micro-bullets" (glass microspheres) are irradiated by a laser pulse with a 10?ns duration in a dynamic process. Experimental parameters such as the microsphere diameter and the laser pulse energy are varied to investigate their influence on laser pulse propulsion. The energy field and spatial intensity distribution in the capillary tube were simulated using a three-dimensional finite-difference time-domain method. The experimental results demonstrate that the propulsion efficiency is dependent on the laser pulse energy and the microsphere size. The propulsion modes and sources of the propelling force were confirmed through direct observation and theoretical calculation. Waves also generated by light-pressure and thermal expansions assisted the propulsion.

| S-EPMC5701249 | biostudies-other

Acoustofluidic separation of prolate and spherical micro-objects.

Project description:Most microfluidic separation techniques rely largely on object size as a separation marker. The ability to separate micro-objects based on their shape is crucial in various biomedical and chemical assays. Here, we develop an on-demand, label-free acoustofluidic method to separate prolate ellipsoids from spherical microparticles based on traveling surface acoustic wave-induced acoustic radiation force and torque. The freely rotating non-spherical micro-objects were aligned under the progressive acoustic field by the counterrotating radiation torque, and the major axis of the prolate ellipsoids was parallel to the progressive wave propagation. The specific alignment of the ellipsoidal particles resulted in a reduction in the cross-sectional area perpendicular to the wave propagation. As a consequence, the acoustic backscattering decreased, resulting in a decreased magnitude of the radiation force. Through the variation in radiation force, which depended on the micro-object morphology enabled the acoustofluidic shape-based separation. We conducted numerical simulations for the wave scattering of spherical and prolate objects to elucidate the working mechanism underlying the proposed method. A series of experiments with polystyrene microspheres, prolate ellipsoids, and peanut-shaped microparticles were performed for validation. Through quantitative analysis of the separation efficiency, we confirmed the high purity and high recovery rate of the proposed acoustofluidic shape-based separation of micro-objects. As a bioparticle, we utilize Thalassiosira eccentrica to perform shape-based separation, as the species has a variety of potential applications in drug delivery, biosensing, nanofabrication, bioencapsulation and immunoisolation.

| S-EPMC10784511 | biostudies-literature

Reversed Janus Micro/Nanomotors with Internal Chemical Engine.

Project description:Self-motile Janus colloids are important for enabling a wide variety of microtechnology applications as well as for improving our understanding of the mechanisms of motion of artificial micro- and nanoswimmers. We present here micro/nanomotors which possess a reversed Janus structure of an internal catalytic "chemical engine". The catalytic material (here platinum (Pt)) is embedded within the interior of the mesoporous silica (mSiO2)-based hollow particles and triggers the decomposition of H2O2 when suspended in an aqueous peroxide (H2O2) solution. The pores/gaps at the noncatalytic (Pt) hemisphere allow the exchange of chemical species in solution between the exterior and the interior of the particle. By varying the diameter of the particles, we observed size-dependent motile behavior in the form of enhanced diffusion for 500 nm particles, and self-phoretic motion, toward the nonmetallic part, for 1.5 and 3 ?m ones. The direction of motion was rationalized by a theoretical model based on self-phoresis. For the 3 ?m particles, a change in the morphology of the porous part is observed, which is accompanied by a change in the mechanism of propulsion via bubble nucleation and ejection as well as a change in the direction of motion.

| S-EPMC5228041 | biostudies-literature

Electrically-triggered micro-explosion in a graphene/SiO2/Si structure.

Project description:Electrically-triggered micro-explosions in a metal-insulator-semiconductor (MIS) structure can fragment/atomize analytes placed on it, offering an interesting application potential for chip-scale implementation of atomic emission spectroscopy (AES). We have investigated the mechanisms of micro-explosions occurring in a graphene/SiO2/Si (GOS) structure under a high-field pulsed voltage drive. Micro-explosions are found to occur more readily in inversion bias than in accumulation bias. Explosion damages in inversion-biased GOS differ significantly between n-Si and p-Si substrate cases: a highly localized, circular, protruding cone-shape melt of Si for the n-Si GOS case, whereas shallow, irregular, laterally-propagating trenches in SiO2/Si for the p-Si GOS case. These differing damage morphologies are explained by different carrier-multiplication processes: in the n-Si case, impact ionization propagates from SiO2 to Si, causing highly-localized melt explosions of Si in the depletion region, whereas in the p-Si case, from SiO2 towards graphene electrode, resulting in laterally wide-spread micro-explosions. These findings are expected to help optimize the GOS-based atomizer structure for low voltage, small-volume analyte, high sensitivity chip-scale emission spectroscopy.

| S-EPMC5943326 | biostudies-literature

OmicsDI is part of the ELIXIR infrastructure

OmicsDI is an Elixir interoperability service. Learn more ›

Tweets

OmicsDI Databases

PRIDE
PeptideAtlas
MassIVE
JPOST Repository
Physiome Model Repository

EGA
EVA
ENA
LINCS
PAXDB
Cell Collective

MetaboLights
Metabolomics Workbench
MetabolomeExpress
GNPS
BioModels
FAIRDOMHub

ArrayExpress
dbGaP
ExpressionAtlas
GEO
NODE

Information

Databases
Help
API
Contact us
Code on GitHub
Terms of use
Submit Data