6 The Dynamics of Water Molecules Confined in the Interior of DMPC. . .
93
0.06
280K
300K
320K
0.05
0.04
0.03
0.02
0.01
0.00
0
1
2
3
r [Å]
g (r )
4
5
6
Fig. 6.3 The radial distribution function g(r) of the center of mass of water molecules confined in
reverse micelle formed from 58 DMPC molecules
where k B is the Boltzmann constant and E A is the activation energy. Fitting data
using Arrhenius law (see Figs. 6.6 and 6.7) allowed us to estimate the diffusion
activation energy E A and D 0 coefficient (Table 6.2), both for confined and bulk
water.
The obtained values of the diffusion activation energy E A for bulk water are
at least two times lower than for corresponding values for confined water. This is
consistent with the obtained values of diffusion coefficients (see Table 6.1).
In conclusion, the simulation results show that the dynamics of water molecules
in reverse micelle 58 DMPC is significantly constrained in comparison to bulk water
sample. Future studies taking into account the reverse micelles of various sizes and
formed from other surfactant aggregates would be of interest.