Autonomous Formation and Annealing of Colloidal Crystals Induced by Light‐Powered Oscillations of Active Particles

Altemose, Alicia; Harris, Aaron J.; Sen, Ayusman

doi:10.1002/syst.201900021

Cited by 13 publications

(6 citation statements)

References 36 publications

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“…However, this is not required for a swarming wave, because colloidal particles are in this case merely flow tracers. Swarming waves have been observed with pure Ag or Ag 3 PO 4 microparticles and nanoparticles (21,24,25,50) (see movie S11 for a demonstration from our own laboratory). We have even seen it on glass slides coated with Ag (fig.…”

Section: Necessary Ingredients For Colloidal Waves To Occurmentioning

confidence: 99%

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Unraveling the physiochemical nature of colloidal motion waves among silver colloids

Chen

Zhou

et al. 2022

Sci. Adv.

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Traveling waves are common in biological and synthetic systems, including the recent discovery that silver (Ag) colloids form traveling motion waves in H 2 O 2 and under light. Here, we show that this colloidal motion wave is a heterogeneous excitable system. The Ag colloids generate traveling chemical waves via reaction-diffusion, and either self-propel through self-diffusiophoresis (“ballistic waves”) or are advected by diffusio-osmotic flows from gradients of neutral molecules (“swarming waves”). Key results include the experimental observation of traveling waves of OH − with pH-sensitive fluorescent dyes and a Rogers-McCulloch model that qualitatively and quantitatively reproduces the key features of colloidal waves. These results are a step forward in elucidating the Ag-H 2 O 2 -light oscillatory system at individual and collective levels. In addition, they pave the way for using colloidal waves either as a platform for studying nonlinear phenomena, or as a tool for colloidal transport and for information transmission in microrobot ensembles.

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Section: Necessary Ingredients For Colloidal Waves To Occurmentioning

confidence: 99%

“…The recent discoveries of photochemically active, oscillating silver-containing colloids (21)(22)(23)(24)(25) have ushered in a new member to this exciting family of nonlinear processes. An inert polymer microsphere half-coated with silver (an "active colloid"; Fig.…”

Section: Introductionmentioning

confidence: 99%

Unraveling the physiochemical nature of colloidal motion waves among silver colloids

Chen

Zhou

et al. 2022

Sci. Adv.

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“…Although an earlier study by us has shown that, 57 under continuous illumination, tracer particles were periodically repelled and attracted from a Ag Janus oscillating motors, regular crystals were never observed, unlike the case with oscillating Ag 3 PO 4 microparticles. 59 However, upon intermittent illumination at 5 Hz, negatively charged SiO 2 microspheres rapidly migrated and assembled around clusters of Ag Janus particles that were stuck on the substrate, forming crystalline clusters within seconds. A closer look reveals that SiO 2 microspheres were attracted more strongly than being repelled as light was turned off and on, respectively, thus achieving a net migration over time.…”

Section: Resultsmentioning

confidence: 99%

Temporal Light Modulation of Photochemically Active, Oscillating Micromotors: Dark Pulses, Mode Switching, and Controlled Clustering

Chen

Zhou

Peng

et al. 2020

ACS Appl. Mater. Interfaces

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Photochemically powered micromotors are prototype microrobots, and spatiotemporal control is pivotal for a wide range of potential applications. Although their spatial navigation has been extensively studied, temporal control of photoactive micromotors remains much less explored. Using Ag-based oscillating micromotors as a model system, a strategy is presented for the controlled modulation of their individual and collective dynamics via periodically switching illumination on and off. In particular, such temporal light modulation drives individual oscillating micromotors into a total of six regimes of distinct dynamics, as the light-toggling frequencies vary from 0 to 10 3 Hz. On an ensemble level, toggling light at 5 Hz gives rise to controlled, reversible clustering of oscillating micromotors and self-assembly of tracer microspheres into colloidal crystals. A qualitative mechanism based on Ag-catalyzed decomposition of H 2 O 2 is given to account for some, but not all, of the above observations. This study might potentially inspire more sophisticated temporal control of micromotors and the development of smart, biomimetic materials that respond to environmental stimuli that not only change in space but also in time.

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“…Plasmonic active matter uses light to power the locomotion and/or self-assembly in various applications. [13][14][15][16] Alternatively, plasmonic enhancement has been used as a sensing mechanism within MOFs where there are metal particles impregnating the MOF or the MOF is grown around metal nano particles. [17][18][19] These techniques require an independent metal particle to be associated with the MOF, and does not provide locomotion to the particle.…”

Section: Introductionmentioning

confidence: 99%

Exploring MOF-based micromotors as SERS sensors

Languirand,

Parrilla,

Smith

et al. 2024

Smart Biomedical and Physiological Sensor Technology XXI

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Active matter, such as Janus micromotors have been used for applications such as self-assembly, pollution mitigation, and drug delivery. Metal-organic framework (MOF)-based Janus micromotors have been recently explored as a method to increase the rate of decontamination for chemical warfare agents in solution due to favorable MOF-chemical interactions. To achieve active-matter decontamination, SiO2@UiO66@Ag MOF-based Janus micromotors were synthesized. In addition to decontamination, the MOF-based micromotors have favorable surface topography for maintaining a localized surface plasmon. This work explores the plasmonic capabilities of Ag@MOF Janus micromotors by systematically changing the amount of Ag, the size of the microparticle that is being used for the plasmonic sensing, and the underlying MOF structure. By changing these parameters, MOF-based micromotors may be able to be used as sensors by utilizing techniques such as surface enhanced Raman spectroscopy (SERS).

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Autonomous Formation and Annealing of Colloidal Crystals Induced by Light‐Powered Oscillations of Active Particles

Cited by 13 publications

References 36 publications

Unraveling the physiochemical nature of colloidal motion waves among silver colloids

Unraveling the physiochemical nature of colloidal motion waves among silver colloids

Temporal Light Modulation of Photochemically Active, Oscillating Micromotors: Dark Pulses, Mode Switching, and Controlled Clustering

Exploring MOF-based micromotors as SERS sensors

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