11 research outputs found
Catalytic Micromotors Moving Near Polyelectrolyte-Modified Substrates: The Roles of Surface Charges, Morphology, and Released Ions
Synthetic microswimmers,
or micromotors, are finding potential uses in a wide range of applications,
most of which involve boundaries. However, subtle yet important effects
beyond physical confinement on the motor dynamics remain less understood.
In this letter, glass substrates were functionalized with positively
and negatively charged polyelectrolytes, and the dynamics of micromotors
moving close to the modified surfaces was examined. Using acoustic
levitation and numerical simulation, we reveal how the speed of a
chemically propelled micromotor slows down significantly near a polyelectrolyte-modified
surface by the combined effects of surface charges, surface morphology,
and ions released from the films
Catalytic Micromotors Moving Near Polyelectrolyte-Modified Substrates: The Roles of Surface Charges, Morphology, and Released Ions
Synthetic microswimmers,
or micromotors, are finding potential uses in a wide range of applications,
most of which involve boundaries. However, subtle yet important effects
beyond physical confinement on the motor dynamics remain less understood.
In this letter, glass substrates were functionalized with positively
and negatively charged polyelectrolytes, and the dynamics of micromotors
moving close to the modified surfaces was examined. Using acoustic
levitation and numerical simulation, we reveal how the speed of a
chemically propelled micromotor slows down significantly near a polyelectrolyte-modified
surface by the combined effects of surface charges, surface morphology,
and ions released from the films
Deforestation for pastures in Central America: the last fifteen years
Micromotors are an
emerging class of micromachines that could find
potential applications in biomedicine, environmental remediation,
and microscale self-assembly. Understanding their propulsion mechanisms
holds the key to their future development. This is especially true
for a popular category of micromotors that are driven by asymmetric
surface photochemical reactions. Many of these micromotors release
ionic species and are propelled via a mechanism termed “ionic
self-diffusiophoresis”. However, exactly how it operates remains
vague. To address this fundamental yet important issue, we have developed
a dielectric-AgCl Janus micromotor that clearly moves away from the
AgCl side when exposed to UV or strong visible light. Taking advantage
of numerical simulations and acoustic levitation techniques, we have
provided tentative explanations for its speed decay over time as well
as its directionality. In addition, photoactive AgCl micromotors demonstrate
interesting gravitactic behaviors that hint at three-dimensional transport
or sensing applications. The current work presents a well-controlled
and easily fabricated model system to understand chemically powered
micromotors, highlighting the usefulness of acoustic levitation for
studying active matter free from the effect of boundaries
Photochemically Powered AgCl Janus Micromotors as a Model System to Understand Ionic Self-Diffusiophoresis
Micromotors are an
emerging class of micromachines that could find
potential applications in biomedicine, environmental remediation,
and microscale self-assembly. Understanding their propulsion mechanisms
holds the key to their future development. This is especially true
for a popular category of micromotors that are driven by asymmetric
surface photochemical reactions. Many of these micromotors release
ionic species and are propelled via a mechanism termed “ionic
self-diffusiophoresis”. However, exactly how it operates remains
vague. To address this fundamental yet important issue, we have developed
a dielectric-AgCl Janus micromotor that clearly moves away from the
AgCl side when exposed to UV or strong visible light. Taking advantage
of numerical simulations and acoustic levitation techniques, we have
provided tentative explanations for its speed decay over time as well
as its directionality. In addition, photoactive AgCl micromotors demonstrate
interesting gravitactic behaviors that hint at three-dimensional transport
or sensing applications. The current work presents a well-controlled
and easily fabricated model system to understand chemically powered
micromotors, highlighting the usefulness of acoustic levitation for
studying active matter free from the effect of boundaries
Photochemically Powered AgCl Janus Micromotors as a Model System to Understand Ionic Self-Diffusiophoresis
Micromotors are an
emerging class of micromachines that could find
potential applications in biomedicine, environmental remediation,
and microscale self-assembly. Understanding their propulsion mechanisms
holds the key to their future development. This is especially true
for a popular category of micromotors that are driven by asymmetric
surface photochemical reactions. Many of these micromotors release
ionic species and are propelled via a mechanism termed “ionic
self-diffusiophoresis”. However, exactly how it operates remains
vague. To address this fundamental yet important issue, we have developed
a dielectric-AgCl Janus micromotor that clearly moves away from the
AgCl side when exposed to UV or strong visible light. Taking advantage
of numerical simulations and acoustic levitation techniques, we have
provided tentative explanations for its speed decay over time as well
as its directionality. In addition, photoactive AgCl micromotors demonstrate
interesting gravitactic behaviors that hint at three-dimensional transport
or sensing applications. The current work presents a well-controlled
and easily fabricated model system to understand chemically powered
micromotors, highlighting the usefulness of acoustic levitation for
studying active matter free from the effect of boundaries
Photochemically Powered AgCl Janus Micromotors as a Model System to Understand Ionic Self-Diffusiophoresis
Micromotors are an
emerging class of micromachines that could find
potential applications in biomedicine, environmental remediation,
and microscale self-assembly. Understanding their propulsion mechanisms
holds the key to their future development. This is especially true
for a popular category of micromotors that are driven by asymmetric
surface photochemical reactions. Many of these micromotors release
ionic species and are propelled via a mechanism termed “ionic
self-diffusiophoresis”. However, exactly how it operates remains
vague. To address this fundamental yet important issue, we have developed
a dielectric-AgCl Janus micromotor that clearly moves away from the
AgCl side when exposed to UV or strong visible light. Taking advantage
of numerical simulations and acoustic levitation techniques, we have
provided tentative explanations for its speed decay over time as well
as its directionality. In addition, photoactive AgCl micromotors demonstrate
interesting gravitactic behaviors that hint at three-dimensional transport
or sensing applications. The current work presents a well-controlled
and easily fabricated model system to understand chemically powered
micromotors, highlighting the usefulness of acoustic levitation for
studying active matter free from the effect of boundaries
Photochemically Powered AgCl Janus Micromotors as a Model System to Understand Ionic Self-Diffusiophoresis
Micromotors are an
emerging class of micromachines that could find
potential applications in biomedicine, environmental remediation,
and microscale self-assembly. Understanding their propulsion mechanisms
holds the key to their future development. This is especially true
for a popular category of micromotors that are driven by asymmetric
surface photochemical reactions. Many of these micromotors release
ionic species and are propelled via a mechanism termed “ionic
self-diffusiophoresis”. However, exactly how it operates remains
vague. To address this fundamental yet important issue, we have developed
a dielectric-AgCl Janus micromotor that clearly moves away from the
AgCl side when exposed to UV or strong visible light. Taking advantage
of numerical simulations and acoustic levitation techniques, we have
provided tentative explanations for its speed decay over time as well
as its directionality. In addition, photoactive AgCl micromotors demonstrate
interesting gravitactic behaviors that hint at three-dimensional transport
or sensing applications. The current work presents a well-controlled
and easily fabricated model system to understand chemically powered
micromotors, highlighting the usefulness of acoustic levitation for
studying active matter free from the effect of boundaries
Photochemically Powered AgCl Janus Micromotors as a Model System to Understand Ionic Self-Diffusiophoresis
Micromotors are an
emerging class of micromachines that could find
potential applications in biomedicine, environmental remediation,
and microscale self-assembly. Understanding their propulsion mechanisms
holds the key to their future development. This is especially true
for a popular category of micromotors that are driven by asymmetric
surface photochemical reactions. Many of these micromotors release
ionic species and are propelled via a mechanism termed “ionic
self-diffusiophoresis”. However, exactly how it operates remains
vague. To address this fundamental yet important issue, we have developed
a dielectric-AgCl Janus micromotor that clearly moves away from the
AgCl side when exposed to UV or strong visible light. Taking advantage
of numerical simulations and acoustic levitation techniques, we have
provided tentative explanations for its speed decay over time as well
as its directionality. In addition, photoactive AgCl micromotors demonstrate
interesting gravitactic behaviors that hint at three-dimensional transport
or sensing applications. The current work presents a well-controlled
and easily fabricated model system to understand chemically powered
micromotors, highlighting the usefulness of acoustic levitation for
studying active matter free from the effect of boundaries
Thermal Transport in Supported Graphene Nanomesh
Graphene
is considered as a promising candidate material to replace silicon
for the next-generation nanoelectronics because of its superb carrier
mobility. To evaluate its thermal dissipation capability as electronic
materials, the thermal transport in monolayer graphene was extensively
explored over the past decade. However, the supported chemical vapor
deposition (CVD) grown monolayer graphene with submicron structures
were seldom studied, which is important for practical nanoelectronics.
Here we investigate the thermal transport properties in a series of
CVD graphene nanomeshes patterned by a hard-template-assisted etching
method. The experimental and numerical results uncovered the phonon
backscattering at hole boundary (<100 nm neck width) and its substantial
contribution to the thermal conductivity reduction
Solution-Processed CdS/Cu<sub>2</sub>S Superlattice Nanowire with Enhanced Thermoelectric Property
Previously,
the solution-based cation exchange reaction has been
extensively studied for the synthesis of the complex heteroepitaxial
nanocolloidals. Here, we demonstrated that the strain induced selective
phase segregation technique can also be applied to large size nanowires
in a well-studied CdS/Cu<sub>2</sub>S system, leading to the formation
of superlattice nanowire structure with a simple solution-based cation
exchange reaction. This structural evolution is driven by the distinct
interface formation energy at different CdS facets as indicated by
ab initio calculation. Because of the energy filtering effect, the
superlattice nanowire shows an enhanced thermopower without significant
decrease of the electrical conductivity. This study provides a promising
low-cost solution process to produce superlattice nanostructures for
practical thermoelectric applications