Dynamic Light Scattering

Ardalan Hayati Far

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2014 رویرهش 18 هبنشراهچ

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Rayleigh Scattering

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Mie Scattering

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What is DLS?

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2014 رویرهش 18 هبنشراهچ

© 2011 HORIBA, Ltd. All rights reserved.

Particle Diameter ( m)0.01 0.1 1 10 100 1000

Colloidal

Suspensions and Slurries

DLS – SZ-100

Electron Microscope

Powders

Fine Coarse

Microscopy PSA300

Laser Diffraction – LA-950

Acoustic Spectroscopy – DT-1201 and DT-300(Zeta)

Electrozone Sensing

Disc-Centrifuge (CPS)

Light Obscuration

0.001

Macromolecules

Nano-Metric

Met

hods

Met

hods

App

sA

pps

Siz

esS

izes

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Particle Size

2014 رویرهش 18 هبنشراهچ

© 2011 HORIBA, Ltd. All rights reserved.

DLS signalRandom motion of particles leads to random fluctuations in signal (due to changing constructive/destructive interference of scattered light.

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A Typical Speckle Pattern

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!"#$%&'%()#*&#%Brownian Motion

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Stokes-Einstein Equation

D diffusion coefficient

k is the Boltzmann constant

T is the temperature

η is the viscosity of the solution

R the hydrodynamic radius of the particle

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The Core

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Molecular Weight

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Hydrodynamic Radius

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95 9595

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© 2011 HORIBA, Ltd. All rights reserved.

Hydrodynamic SizeThe instrument reports the size of sphere that moves (diffuses) like your particle.This size will include any stabilizers bound to the molecule (even if they are not seen by TEM).

SEM (above) and TEM (below) images for RM 8011

Technique Size nmAtomic Force Microscopy 8.5 ± 0.3

Scanning Electron Microscopy 9.9 ± 0.1

Transmission Electron Microscopy 8.9 ± 0.1

Dynamic Light Scattering 13.5 ± 0.1

Gold Colloids

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Why DLS?

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