[gmx-users] Re: Forming a micelles

Alif M Latif prism_dead at yahoo.com
Fri Sep 26 10:58:48 CEST 2008

Dear Lin,
I have suggestions:

Micelles should (theoretically) form above the CMC. So if you want a micelle, the concentration should be >>CMC
I suggest that you find the CMC experimentally, then convert the concentration to nm^3 (let say: mv/1000nm^3)
The number of molecules should be able to obtained by multiplying with Avogadro number: (6.023x10^23). If your system contain co-surfactant, then you'll need to get the experimetal CMC for at least one of the two surfactants (if both non-ionic..if not you'll need the activity coefficient for each surfactant).Take a look at this paper:

Bourov G. K. and Bhattacharya A., Brownian dynamics of mixed surfactant micelles, Journal of Chemical Physics, 123 (2005) 204712(1)-204712(6)
How long 600 ps simulation is depends on your system size, box type, parameters and computational power (see manual).
One other way to KNOW the surfactants formed micelle is by measuring the surface tension (use g_energy). But g_energy gives surface*surface tension value, so you'll need to work on that. (HINT: Surface tension value drop drastically at CMC)

Hope these helps,

Muhammad Alif Mohammad Latif 
Department of Chemistry
Faculty of Science
Universiti Putra Malaysia
43400 UPM Serdang, Selangor

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://maillist.sys.kth.se/pipermail/gromacs.org_gmx-users/attachments/20080926/a973518a/attachment.html>

More information about the gromacs.org_gmx-users mailing list