Caracteriza o de nanoparticulas e nanoestruturas aula 10 qf933 instituto de qu mica unicamp
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CARACTERIZAÇÃO DE NANOPARTICULAS E NANOESTRUTURAS Aula 10 QF933 Instituto de Química UNICAMP PowerPoint PPT Presentation


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CARACTERIZAÇÃO DE NANOPARTICULAS E NANOESTRUTURAS Aula 10 QF933 Instituto de Química UNICAMP. Nanoparticles Characterization: Measurement of the particles size by the PCS technique. MSc. Priscyla D. Marcato Dr. Nelson Durán. Principle of Measurement.

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CARACTERIZAÇÃO DE NANOPARTICULAS E NANOESTRUTURAS Aula 10 QF933 Instituto de Química UNICAMP

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Caracteriza o de nanoparticulas e nanoestruturas aula 10 qf933 instituto de qu mica unicamp

CARACTERIZAÇÃO DE NANOPARTICULAS E NANOESTRUTURASAula 10 QF933Instituto de QuímicaUNICAMP


Caracteriza o de nanoparticulas e nanoestruturas aula 10 qf933 instituto de qu mica unicamp

Nanoparticles Characterization:

Measurement of the particles size by the PCS technique

MSc. Priscyla D. Marcato

Dr. Nelson Durán


Caracteriza o de nanoparticulas e nanoestruturas aula 10 qf933 instituto de qu mica unicamp

Principle of Measurement

  • If the particles or molecules are illuminated with a laser, the intensity of the scattered light fluctuates at a rate that is dependent upon the size of the particles

  • Analysis of these intensity fluctuations yields the velocity of the Brownian motion and hence the particle size using the Stokes-Einstein relationship.


Brownian motion

Brownian Motion

Particles, emulsions and molecules in suspension undergo Brownian motion.

This is the motion induced by the bombardment by solvent molecules that themselves are moving due to their thermal energy

Temperature and viscosity must be known


Caracteriza o de nanoparticulas e nanoestruturas aula 10 qf933 instituto de qu mica unicamp

Intensity of the scattered light fluctuates


Intensity of the scattered light fluctuates

Intensity of the scattered light fluctuates

Small particles- noisy curve

Large particles- smooth curve


Caracteriza o de nanoparticulas e nanoestruturas aula 10 qf933 instituto de qu mica unicamp

Stokes-Einstein relationship

The velocity of the Brownian motion is defined by a property known as the translational diffusion coefficient (usually given the symbol, D).


Caracteriza o de nanoparticulas e nanoestruturas aula 10 qf933 instituto de qu mica unicamp

He-Ne Laser

 = 633 nm

Zetasizer Nano ZS

Malvern


Caracteriza o de nanoparticulas e nanoestruturas aula 10 qf933 instituto de qu mica unicamp

Determining particle size

Determined autocorrelation function

Depend


Caracteriza o de nanoparticulas e nanoestruturas aula 10 qf933 instituto de qu mica unicamp

Correlation function Correlograms


Caracteriza o de nanoparticulas e nanoestruturas aula 10 qf933 instituto de qu mica unicamp

Correlogram from a sample containing large particles

Correlogram from a sample containing small particles


Caracteriza o de nanoparticulas e nanoestruturas aula 10 qf933 instituto de qu mica unicamp

Low

concentration

turbidity is linear with concentration

Particles are so close together that the scattered radiation is re-scattered by other particles.

High

concentration


Caracteriza o de nanoparticulas e nanoestruturas aula 10 qf933 instituto de qu mica unicamp

Optical arrangement in 173°

backscatter detection


Information

Information

Size by:

- Intensity

I  d6

Rayleigh Scattering

(For nanoparticles less than d =λ/10 or around 60nm the scattering will be equal in all

Directions-isotropic)


Caracteriza o de nanoparticulas e nanoestruturas aula 10 qf933 instituto de qu mica unicamp

8 nm

80 nm

This particles will scatter 106 (one million) times more light than the small particle (8 nm)

The contribution to the total light scattered by the small particles will be extremely small


Caracteriza o de nanoparticulas e nanoestruturas aula 10 qf933 instituto de qu mica unicamp

8

80


Caracteriza o de nanoparticulas e nanoestruturas aula 10 qf933 instituto de qu mica unicamp

By the Mie theory is possible convert intensity distribution into volume

V= 4r3

r = d/2

V= 4(d/2)3 = 4d3

8

- Volume

 d3

- Number

 d1


Caracteriza o de nanoparticulas e nanoestruturas aula 10 qf933 instituto de qu mica unicamp

Two population of spherical nanoparticles :

5 nm and 50 nm

(in equal number)

Which of these distributions should I use?


Caracteriza o de nanoparticulas e nanoestruturas aula 10 qf933 instituto de qu mica unicamp

d(intensity) > d(volume) > d(number)


Caracteriza o de nanoparticulas e nanoestruturas aula 10 qf933 instituto de qu mica unicamp

Direct determination of the number-weighted mean radius and polydispersity from dynamic light-scattering data

Philipus et al.,Applied Optics, 45, 2209 (2006)

We find that converting intensity-weighted distributions is not always reliable, especially when the polydispersity of the sample is large.


Caracteriza o de nanoparticulas e nanoestruturas aula 10 qf933 instituto de qu mica unicamp

Reference

Dynamic Light Scattering:An Introduction in 30 Minutes, Malvern, http://www.malvern.co.uk/common/downloads/campaign/MRK656-01.pdf


Caracteriza o de nanoparticulas e nanoestruturas aula 10 qf933 instituto de qu mica unicamp

HOMOGENEIZAÇÃO À ALTA PRESSÃO


Caracteriza o de nanoparticulas e nanoestruturas aula 10 qf933 instituto de qu mica unicamp

Ativo + Lipídio fundido

Homogeneização a frio

Homogeneização a quente

Solidificação

(nitrogênio líquido)

Solução de tensoativo (quente)

(sob alta agitação)

Moído (micropartículas lipídicas)

Agitação

Solução de tensoativo (fria)

Pré-emulsão

Micro-suspensão

Homogeneizado à alta Pressão


Caracteriza o de nanoparticulas e nanoestruturas aula 10 qf933 instituto de qu mica unicamp

Homogeneização à

Alta Pressão

  • Rápido e Fácil

  • Fácil escalonamento - 99% de reprodutibilidade em escala industrial

  • Evita contaminação no processo de homogeneização


Caracteriza o de nanoparticulas e nanoestruturas aula 10 qf933 instituto de qu mica unicamp

Espectroscopia de Correlação de Fótons


Caracteriza o de nanoparticulas e nanoestruturas aula 10 qf933 instituto de qu mica unicamp

Espectroscopia de Correlação de Fótons

Diâmetro


Caracteriza o de nanoparticulas e nanoestruturas aula 10 qf933 instituto de qu mica unicamp

Espectroscopia de Correlação de Fótons

Potencial Zeta


Caracteriza o de nanoparticulas e nanoestruturas aula 10 qf933 instituto de qu mica unicamp

  • Rápido e Fácil

  • Fácil escalonamento - 99% de reprodutibilidade em escala industrial

  • Evita contaminação no processo de homogeneização


Caracteriza o de nanoparticulas e nanoestruturas aula 10 qf933 instituto de qu mica unicamp

Dingler e Gohla, J.Microencapsul.

19, 11-16 (2002).


Caracteriza o de nanoparticulas e nanoestruturas aula 10 qf933 instituto de qu mica unicamp

500 bar 3 ciclos

Sakulkhul et al., Proceedings

of the 2nd IEEE International

( 2007)


Microscopia eletronica de varredura sem

MICROSCOPIA ELETRONICA DE VARREDURA (SEM)


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