Charged interfaces

From Soft-Matter
Revision as of 21:31, 5 January 2009 by MichaelPetralia (Talk | contribs)

Jump to: navigation, search



"My own understanding of the need for a fundamental approach to modern electrostatics came from two sources. One was the electrostatics lecture-demonstrations of A.D. Moore, which often leaves experts in electromagnetics amazed by seemingly impossible phenomena. The other was my colleagues in industry, especially Henry Till, who routinely showed that complicated solutions of Laplace's equation had little to do with understanding and using electrostatics." J.M Crowley in Fundamentals of electrostatics."


Interesting Tidbits

Non-smoker attracts smoker's smoke?

Non-smokers complain quite often that they seem to attract cigarette smoke. Smokers regard this as a fairy tale, or else a method to make them stop smoking. However, things are slightly more complex. Measurements carried out with an ion counter show that cigarette smoke carries a predominantly positive charge. The negative charges are flowing to ground through the hand or mouth of the smoker.


Let us assume a situation similar to the figure above. The smoker produces a cloud of positive charged particles and, because previous clouds have also charged the smoker’s clothes positively, the particle cloud is repelled. Because the TV screen is also charged positively, it also repels the cloud. On the other hand, the non-smoker is not charged, being more or less neutral. The repelled smoke particles will thus indeed flow in the direction of the non-smoker. When the non-smoker wears clothing containing polyethylene or rayon fibers, then it is likely that he/she is charged negatively according to the triboelectric series. He/she will then attract the smoke particles.

This also explains why a single visit or meet-up with a smoker will leave the house/clothing of a non-smoker smelling bad for a long time. The gravitational settling of smoke particles also mean that children will be affected more by this selective deposition.

Nose will also serve as preferred deposition site. However, in our case, the nose of a non-smoker will be neutrally charged and the smoke will be positively charged.

Source: The forgotten pollution by Rein A Roos

Extended Reading

  • Derjaguin (1986)
    • Chapter 6.1 – 6.2
  • Derjaguin (1989)
    • Chapter 6. Electrostatic component of disjoining pressure
  • Evans
    • Chapter 3. Electrostatic interactions in colloidal systems
  • Morrison
    • Chapter 17. Electrical charges in dispersions
  • Norde
    • Chapter 9. Electrochemistry of interfaces
    • Chapter 10. Electrokinetic phenomena

Top of Page