Display Settings:

Format

Send to:

Choose Destination
See comment in PubMed Commons below
Phys Rev Lett. 2007 Jul 6;99(1):018303. Epub 2007 Jul 6.

Statistics of particle trajectories at short time intervals reveal fN-scale colloidal forces.

Author information

  • 1Department of Mechanical Engineering, Yale University, New Haven, Connecticut 06511, USA.

Abstract

We describe and implement a technique for extracting forces from the relaxation of an overdamped thermal system with normal modes. At sufficiently short time intervals, the evolution of a normal mode is well described by a one-dimensional Smoluchowski equation with constant drift velocity v, and diffusion coefficent D. By virtue of fluctuation dissipation, these transport coefficients are simply related to conservative forces, F, acting on the normal mode: F=kBTv/D. This relationship implicitly accounts for hydrodynamic interactions, requires no mechanical calibration, makes no assumptions about the form of conservative forces, and requires no prior knowledge of material properties. We apply this method to measure the electrostatic interactions of polymer microspheres suspended in nonpolar microemulsions.

PMID:
17678194
[PubMed - indexed for MEDLINE]
PubMed Commons home

PubMed Commons

0 comments
How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for American Physical Society
    Loading ...
    Write to the Help Desk