Research & Development World

  • R&D World Home
  • Topics
    • Aerospace
    • Automotive
    • Biotech
    • Careers
    • Chemistry
    • Environment
    • Energy
    • Life Science
    • Material Science
    • R&D Management
    • Physics
  • Technology
    • 3D Printing
    • A.I./Robotics
    • Software
    • Battery Technology
    • Controlled Environments
      • Cleanrooms
      • Graphene
      • Lasers
      • Regulations/Standards
      • Sensors
    • Imaging
    • Nanotechnology
    • Scientific Computing
      • Big Data
      • HPC/Supercomputing
      • Informatics
      • Security
    • Semiconductors
  • R&D Market Pulse
  • R&D 100
    • Call for Nominations: The 2025 R&D 100 Awards
    • R&D 100 Awards Event
    • R&D 100 Submissions
    • Winner Archive
    • Explore the 2024 R&D 100 award winners and finalists
  • Resources
    • Research Reports
    • Digital Issues
    • R&D Index
    • Subscribe
    • Video
    • Webinars
  • Global Funding Forecast
  • Top Labs
  • Advertise
  • SUBSCRIBE

Researchers track nanoparticle dynamics in three dimensions

By R&D Editors | August 2, 2012

Researchers
from the NIST Center for Nanoscale Science and Technology have used
three-dimensional single-particle tracking to measure the dynamic
behavior of individual nanoparticles adsorbed at the surface of
micrometer-scale oil droplets in water.

The
results revealed that the diffusion of the particles depends on their
size, with smaller particles diffusing much more slowly than expected. A
detailed understanding of how colloidal nanoparticles interact with
interfaces is essential for designing them for specific applications in
fields ranging from drug delivery to oil exploration and recovery.

The
researchers developed a feedback control system with real-time control
electronics to actuate a piezoelectric stage, moving the sample in order
to lock the moving nanoparticle in the observation volume of an optical
microscope.

The
technique, which triggers off of photons collected in situ from an
individual fluorescing nanoparticle, provides high resolution
three-dimensional position information with excellent time resolution
and with the added benefit of sensitivity to chemical activity.
Particles ranging in size from 20 nm to 2000 nm were followed in
real-time as they diffused freely in water and over the curved surfaces
of variously-sized oil droplets.

As
expected, the diffusion coefficients scaled with particle size for the
freely diffusing particles. However, there was a significant and
unexpected decrease in the diffusion coefficients for smaller (<200
nm) nanoparticles when they diffused at the oil-water interface.

Furthermore,
for a given particle size, the researchers observed a large spread in
the diffusion coefficients measured at the interface, while no such
effect was observed for the freely diffusing particles. In order to
better fit the measurements, the basic model that works well for larger
particles diffusing at a fluid-fluid interface needed to be modified to
account for line tension (the one-dimensional analogue of surface
tension) at the interface between the smaller nanoparticles, the oil,
and the water.

The
researchers believe that the variability in the diffusion coefficients
of the particles adsorbed at the interface is most probably a reflection
of subtle variations in the surface chemistry of the particles,
suggesting that diffusion measurements may provide a new way to compare
particle surface chemistries. Whereas following the dynamics of isolated
particles provides many useful insights into their behavior, typical
man-made and natural systems are usually far more complex, with
heterogeneous fluids, crowded environments, and strong particle-particle
interactions.

The
researchers believe that using real-time, three-dimensional particle
tracking to observe intentionally inserted, single tracer particles may
provide an ideal tool to probe complicated fluid systems, such as the
interior of cells, or oil/water mixtures trapped inside porous rock.

Three-dimensional real-time tracking of nanoparticles at an oil–water interface

Source: NIST

Related Articles Read More >

KIST carbon nanotube supercapacitor holds capacity after 100,000 cycles
A new wave of metalworking lets semiconductor crystals bend and stretch
LLNL deposits quantum dots on corrugated IR chips in a single step
KATRIN inauguration photo form 2018
Neutrinos pinned below 0.45 eV; KATRIN halves the particle’s mass ceiling
rd newsletter
EXPAND YOUR KNOWLEDGE AND STAY CONNECTED
Get the latest info on technologies, trends, and strategies in Research & Development.
RD 25 Power Index

R&D World Digital Issues

Fall 2024 issue

Browse the most current issue of R&D World and back issues in an easy to use high quality format. Clip, share and download with the leading R&D magazine today.

Research & Development World
  • Subscribe to R&D World Magazine
  • Enews Sign Up
  • Contact Us
  • About Us
  • Drug Discovery & Development
  • Pharmaceutical Processing
  • Global Funding Forecast

Copyright © 2025 WTWH Media LLC. All Rights Reserved. The material on this site may not be reproduced, distributed, transmitted, cached or otherwise used, except with the prior written permission of WTWH Media
Privacy Policy | Advertising | About Us

Search R&D World

  • R&D World Home
  • Topics
    • Aerospace
    • Automotive
    • Biotech
    • Careers
    • Chemistry
    • Environment
    • Energy
    • Life Science
    • Material Science
    • R&D Management
    • Physics
  • Technology
    • 3D Printing
    • A.I./Robotics
    • Software
    • Battery Technology
    • Controlled Environments
      • Cleanrooms
      • Graphene
      • Lasers
      • Regulations/Standards
      • Sensors
    • Imaging
    • Nanotechnology
    • Scientific Computing
      • Big Data
      • HPC/Supercomputing
      • Informatics
      • Security
    • Semiconductors
  • R&D Market Pulse
  • R&D 100
    • Call for Nominations: The 2025 R&D 100 Awards
    • R&D 100 Awards Event
    • R&D 100 Submissions
    • Winner Archive
    • Explore the 2024 R&D 100 award winners and finalists
  • Resources
    • Research Reports
    • Digital Issues
    • R&D Index
    • Subscribe
    • Video
    • Webinars
  • Global Funding Forecast
  • Top Labs
  • Advertise
  • SUBSCRIBE