D.Fairhurst Colloid Consultants Ltd., Congers, NY H.S.Dhadwal, B.Mukherjee SUNY Stony Brook, NY

2. A New, Simple, Inexpensive Method for Non-Invasive Particle Size Measurements of Suspensions and Droplets ™ ™ D.Fairhurst Colloid Consultants Ltd., Congers, NY H.S.Dhadwal, B.Mukherjee SUNY Stony Brook, NY S.W.Race XiGo Nanotools Inc., Morganville, NJ NSTI Nanotech Anaheim, CA May,2005

3. Time-dependent Light Scattering by Any Other Name IFS - Intensity Fluctuation Spectroscopy DLS - Dynamic Light Scattering PCS - Photon Correlation Spectroscopy QELS - Quasi-elastic Light Scattering

4. Light Scattering History 1871 - Rayleigh Scattering Theory 1910 - Einstein Fluctuation Theory 1944 - Debye Theory for Polymer solutions 1964 - Pecora Theory for DLS 1964 - Cummins verifies experimentally 1969 - Pike suggests digital autocorrelator (PCS) 1990’s - Single-mode fiber optics introduced

5. Nanomaterials will require tools for QC & for raw material specification in manufacturing Tools that can be used with minimal training single key-stroke operation Tools that are portable to go where you go, lab-to-plant Tools with customer replaceable parts easily serviced, no down-time Tools priced to fit QC applications New materials demand new solutions to old problems Take the instrument to the application

6. Fiber Optics Classic DLS instrumentation use metal plate of large mass on which to configure the optics. expensive and requires precise alignment Fiber optics arrangements are: More compact More robust Less expensive Many application advantages Remote sensing inaccessible, hostile environments Higher concentration systems dilution, wash cycles and particle concentration effects eliminated

7. Fiber Optics Problems and difficulties with previous fiber optic designs Multimode fibers Reduced intercept/baseline ratio Polarization not preserved Single fiber system Coupling Signal/concentration effects Low  (<0.001) – local oscillator (homodyne) High  (>0.2) – self beating

8. Back Scatter Light Scattering • Fiber optic probe design patented • Eliminates need for directional coupler • Self beating detection of scattered light • Independent control of scattering volume and angle

9. Elliptical Spot shape in the center of the scattering volume: 0.48mm x 0.35mm Back Scatter Light Scattering

10. Brownian Motion of Particles and Fluctuation in Light Intensity Rate of intensity fluctuations varies with size of particles

11. Instantaneous Photon Counts

12. Photon Count Correlation Possible to measure the spectrum of frequencies contained in the intensity fluctuations arising from Brownian motion very inefficient Advent of digital auto correlator makes it easy construct correlation function analyze correlogram various algorithms Cumulants, NNLS, Contin…..

13. Photon Count Correlation • The correlation function, g(2)(: The coherence factor, : s is the spatial coherence factor t is the temporal coherence factor

14. Photon Counting Fluctuations Correlators are extremely complex electronic devices and add a significant cost in the manufacture of a particle sizing instrument It is possible to obtain size information directly from the photon stream, without the need for correlation Photon counting fluctuations represented by a doubly stochastic procedure Poisson process of the random arrival of photons Gaussian process of the Brownian motion

15. Brownian Motion Scattered intensity from particles undergoing Brownian motion has a Lorentzian power spectrum The variance of the random process associated with scattered intensity is: Is is the time average intensity Ts is the sample time  is the Linewidth parameter (Dt q2)

16. Basic Equations Linewidth,  = Dtq2 Scattering Wave Vector, q = 4n sin(/2) o Stokes-Einstein Equation, Dt = kbT 3dh dh is the hydrodynamic particle diameter

17. Consequence of hydrodynamic size Polystyrene Latex Sample Nominal size 105nm Dist. Width = 24nm Sample diluted in 0.01M KCl Avg. Size = 106nm Dist. Width = 24nm Sample diluted in DI water Avg. Size = 113nm Dist. Width = 27nm

18. Coherence Factor Measurement of coherence at several integration times leads to particle size

19. Computation of Particle Size • The computational process can be simplified: • Measurement of coherence at only two integration times • Use of approximations in calculation of the coherence • factor, 

20. Real Time Measurement of Particle Size Diameters from 3nm to 3000nm can be detected

21. Malvern Mastersizer 2000 Malvern Zetasizer Nano PC PC PC Xigo Nanotools Acorn <1 kg, no PC required! 18 kg + PC! 31 kg + PC! Brookhaven BI90 1 VGA VGA VGA 37 kg + PC! Size Comparison and Everyone else!

22. The Particle Sizer Specifications Unit Size: 200 x 100 x 60 mm (LxWxH) Unit Weight: 0.5 Kg Probe dimension: 120mm long 3 mm diameter Viscosity Temperature Compensation Cable length: 0.5 meter (std) up to 100 meter Size Measurement Range: 3 to 3000 nm

23. The Particle Sizer Features Battery operated GUI for easy use USB2.0 data interface CFR21 GMP compliant UL and CE certified Flash Memory Data Storage & Transfer

24. Experimental results using the Nominal Conventional Acorn Particle Size DLS (900) (nm)(nm)(nm) 150 143 148 85 84 85 42 40 43 17 17 17

25. Applications using the

26. Applications using the Particle Size as a function of Concentration for Ludox Silica

27. Applications using the

28. Applications using the

29. Applications using the

30. Applications using the

31. Applications using the

32. Applications using the

33. Applications using the

34. Applications using the Microemulsion Technology Stratification and hydrodynamic instabilities Emulsion Polymerization Particle size growth Biochemical Manufacturing Real-time monitoring Radioactive waste Monitoring Remote sensing

35. Advantages of the in Particle Sizing Portable Fits in your hand Simple to use Can be used in minutes Wide dynamic size range Spans the range Rugged Withstands QC demands Remote measurements Versatile Absolute No calibration Precise Reproducible

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