A Pickering Emulsion Route to Swimming Active Janus Colloids

Archer, Richard J.; Parnell, Andrew J.; Campbell, Andrew I.; Howse, Jonathan R.; Ebbens, Stephen J.

doi:10.1002/advs.201700528

Cited by 60 publications

(66 citation statements)

References 44 publications

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“…There are a few papers that show the influence of interface nanostructure on the motion of the catalytic nano/micromotors . The mesoporous structure together with the interfaces has even been lesser addressed for the case of light‐driven micromotors, which should play the dominant role on the self‐propulsion .…”

Section: Introductionmentioning

confidence: 99%

Catalytic and Light‐Driven ZnO/Pt Janus Nano/Micromotors: Switching of Motion Mechanism via Interface Roughness and Defect Tailoring at the Nanoscale

Pourrahimi

Villa

Palenzuela

et al. 2019

Adv Funct Materials

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The first models of mesoporous ZnO/Pt Janus micromotors that show fuelfree and light-powered propulsion depending on the interface roughness are shown. Two models of ZnO semiconducting particles with distinct surface morphologies and pore structures are synthesized by self-aggregation of primary nanoparticles and nanosheets into nanoscale rough and smooth microparticles, respectively. The self-assembled nanosheet model (smooth) provides a large surface for the formation of a continuous Pt layer with strong adherence, whereas the discontinuous Pt species take place inside the inter-nanoparticles pores in the self-assembled nanoparticle model (rough). The effects of the interface, surface porosity, defect, and charge transfer on the light-powered motion for both well-designed mesoporous ZnO/Pt Janus micromotors are investigated and compared to find the underlying propulsion mechanisms. The degradation of two model pollutants is demonstrated as a proof-of-concept application of these carefully engineered Janus micromotors. In this work, it is shown that by discreet material fabrication together with semiconductor/metal interface charge transport interpretation, it would be possible to develop new light-driven Janus micromotors based on other photocatalysts containing active surfaces such as TiO 2 .

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Section: Introductionmentioning

confidence: 99%

Catalytic and Light‐Driven ZnO/Pt Janus Nano/Micromotors: Switching of Motion Mechanism via Interface Roughness and Defect Tailoring at the Nanoscale

Pourrahimi

Villa

Palenzuela

et al. 2019

Adv Funct Materials

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“…[30] It was recently found that such a change in chemistry also affects oxides, materials usually considered quite stable under electron beam irradiation. [31] This destabilizing effect is also seen for amorphous SiO 2 , an important oxide in many nanoscale applications, [32][33][34] which although stable in vacuum, is severely destabilized by electron beam induced chemistry in water. [35,36] Specifically, it was shown that upon imaging with a scanning electron beam, silica nanospheres tended to elongate in the scanning direction of the beam and shrink significantly over time.…”

mentioning

confidence: 99%

Nanoscale Imaging and Stabilization of Silica Nanospheres in Liquid Phase Transmission Electron Microscopy

Meijerink

Spiga

Hansen

et al. 2018

Part & Part Syst Charact

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Liquid phase transmission electron microscopy (LP‐TEM) is a novel and highly promising technique for the in situ study of important nanoscale processes, in particular the synthesis and modification of various nanostructures in a liquid. Destabilization of the samples, including reduction, oxidation, or dissolution by interactions between electron beam, liquid, and sample, is still one of the main challenges of this technique. This work focuses on amorphous silica nanospheres and the phenomena behind their reshaping and dissolution in LP‐TEM. It is proposed that silica degradation is primarily the result of reducing radical formation in the liquid phase and the subsequent accelerated hydroxylation of the silica, while alterations in silica solid structure, pH, and oxidizing species formation had limited influence. Furthermore, the presence of water vapor instead of liquid water also results in degradation of silica. Most importantly however, it is shown that the addition of scavengers for reducing radicals significantly improved amorphous silica stability during LP‐TEM imaging. Devising such methods to overcome adverse effects in LP‐TEM is of the utmost importance for further development and implementation of this technique in studies of nanoscale processes in liquid.

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“…The scalability is a property hard to fulfill for the planar‐based techniques (rolled‐up planar nanolayers, electrochemical template pore deposition). The answer to the problem is approached by wet‐chemical synthesis of micro/nanoparticles directly in solution, where the primary challenge is to introduce a highly asymmetrical component into the particle, to use it for directional self‐propulsion …”

Section: Introductionmentioning

confidence: 99%

Plasmonic Self‐Propelled Nanomotors for Explosives Detection via Solution‐Based Surface Enhanced Raman Scattering

Novotný

Plutnar

Pumera

2019

Adv Funct Materials

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Nanomotors represent a class of artificial machines that span the chasm between molecular motors and bigger micromotors. Their importance lies in the fact that to effectively navigate and perform tasks in a biological environment without alerting the action of the immune system, the maximal size of the object has to be well below 200 nm. Fully nanosized gold/silver core/shell plasmonic nanomotors using the seeded growth wet chemical approach, which allows high scalability of synthesis of the nanomotors compared to planar substrate-based methods, is presented. Using the nanoparticle tracking analysis, the catalysis driven enhanced diffusion of the plasmonic nanomotors in the presence of low concentrations of fuel is presented and shown that the prepared nanomotors are good candidates for a solutionbased surface-enhanced Raman spectroscopy detection of picric acid, a typical explosive. In addition to the mentioned effects, ligand-exchange is performed on the nanomotors to replace the surfactant with its thiolated analog, a combination which is already proven in literature to be stealthy to the immune response of the living organism.The ORCID identification number(s) for the author(s) of this article can be found under https://doi.org/10.1002/adfm.201903041. microjets, [8][9][10][11] Janus particles, [5,12,13] and particle dimers [11] in the past years, showing the possibility to construct micrometer-sized objects with physically and chemically programmed behavior for a specific environment and specific stimuli. [5,14] Such programmed behavior patterns include catalytically driven bubble-jet propulsion, [8] self-electrophoresis, [15][16][17] self-diffusiophoresis, [15,17] selfthermophoresis, [12,17] which are connected to response to external magnetic, [18] electric, [19] or electromagnetic field [20,21] and also to concentration gradients of chemical substances. [22] These micromachines are proposed to be used in biomedicinal [3] and environmental [4,6] as well as in military applications. [23] Applications of micromotors in sensing of small molecules are also developed but in much smaller extent. The sensing is usually based on (i) slowing the micromotors down by catalyst poisoning or accelerating them by providing fuel, [24,25] (ii) aggregation of the micromotors to produce higher concentrations of an analyte [26] or (iii) separation of the sensing of an analyte by collecting the micromotors be sedimentation. [26] However, direct sensing by micromotors is limited.While the area of self-propelled micromachines is well developed, the field of nanorobots, i.e., self-propelled devices of submicrometer size, is developed much less. For any micro-or nanorobots to have real-world impact, we have to use millions and billions of them. Most of the works in the field use planar substrate-based preparation technique. [17] To further push the micro/nanorobots field to real-world applications, one has to develop objects, whose synthesis is easily scalable. [27] The scalability is a property hard to fulfill for the planar-based...

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A Pickering Emulsion Route to Swimming Active Janus Colloids

Cited by 60 publications

References 44 publications

Catalytic and Light‐Driven ZnO/Pt Janus Nano/Micromotors: Switching of Motion Mechanism via Interface Roughness and Defect Tailoring at the Nanoscale

Catalytic and Light‐Driven ZnO/Pt Janus Nano/Micromotors: Switching of Motion Mechanism via Interface Roughness and Defect Tailoring at the Nanoscale

Nanoscale Imaging and Stabilization of Silica Nanospheres in Liquid Phase Transmission Electron Microscopy

Plasmonic Self‐Propelled Nanomotors for Explosives Detection via Solution‐Based Surface Enhanced Raman Scattering

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