1 / 10

Particle Sizing by DLS

Particle Sizing by DLS. DLS by Particles of Different Sizes. intensity. particle of radius R 1. particle of radius R 2. total. distribution function of G weighted by the scattering intensity. Analysis of Autocorrelation Functions. 1. Cumulant expansion (Unimodal analysis)

adrian-hahn
Download Presentation

Particle Sizing by DLS

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Particle Sizing by DLS

  2. DLS by Particles of Different Sizes intensity particle of radius R1 particle of radius R2 total distribution function of G weighted by the scattering intensity

  3. Analysis of Autocorrelation Functions 1. Cumulant expansion (Unimodal analysis) 2. Inverse-Laplace transform (SDP analysis)

  4. Cumulant Expansion (Unimodal analysis) Curve fitting by a second -order polynomial yields the coefficients. where 1st cumulant 2nd cumulant (polydispersity)

  5. Inverse-Laplace Transform (SDP Analysis) is the Laplace transform of G(G).

  6. Examples of Inverse-Laplace Transform monodisperse unimodal distribution bimodal distribution

  7. Relationship between Unimodal Analysis and SDP Analysis harmonic average weighted by the scattering intensity

  8. Example of a Bimodal Distribution What is the average radius (estimated by DLS) for an equal mass mixture of spheres of two radii R1 and R2? Assume R1 = 10 nm and R2 = 100 nm. The average depends on k. Plot <R> as a function of q. Plot G2/G1 as a function of q.

  9. Diffusion vs. Internal Relaxation

  10. Examples of Internal Relaxation Rotation of a rodlike molecule Rouse normal modes Elastic motions of a gel Reacting system

More Related