Journal of Physical Chemistry B, Vol.114, No.39, 12455-12467, 2010
Similarities and Differences Between Cyclodextrin-Sodium Dodecyl Sulfate Host-Guest Complexes of Different Stoichiometries: Molecular Dynamics Simulations at Several Temperatures
An extensive dynamic and structural characterization of the supramolecular complexes that can be formed by mixing alpha-, beta-, and gamma-cyclodextrin (CD) with sodium dodecyl sulfate (SIDS) in water at 283, 298, and 323 K was performed by means of computational molecular dynamics simulations. For each Cl) at the three temperatures, seven different initial conformations were used, generating a total of 63 trajectories. The observed stoichiometries, intermolecular distances, and relative orientation of the individual molecules in the complexes, as well as the most important interactions which contribute to their stability and the role of the solvent water molecules were studied in detail, revealing clear differences and similarities between the three CDs. Earlier reported findings in the inclusion complexes field are also discussed in the context of the present results. For any of the three native cyclodextrins, the CD2SDS1 species in the head-to-head conformation appears to be a promising building block for nanotubular aggregates both in the bulk and at the solution/air interface, as earlier suggested for the case of alpha-CD. Moreover, the observed noninclusion arrangements involving beta-CD are proposed as the seed for the premicellar (beta-CD)-incluced aggregation of SDS described in the literature.