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    Charged nanorods at heterogeneously charged surfaces

    , Article Journal of Chemical Physics ; Volume 149, Issue 13 , 2018 ; 00219606 (ISSN) Naji, A ; Hejazi, K ; Mahgerefteh, E ; Podgornik, R ; Sharif University of Technology
    Abstract
    We study the spatial and orientational distribution of charged nanorods (rodlike counterions) as well as the effective interaction mediated by them between two plane-parallel surfaces that carry fixed (quenched) heterogeneous charge distributions. The nanorods are assumed to have an internal charge distribution, specified by a multivalent monopolar moment and a finite quadrupolar moment, and the quenched surface charge is assumed to be randomly distributed with equal mean and variance on the two surfaces. While equally charged surfaces are known to repel within the traditional mean-field theories, the presence of multivalent counterions has been shown to cause attractive interactions between... 

    Solvation free energy and solubility of acetaminophen and ibuprofen in supercritical carbon dioxide: Impact of the solvent model

    , Article Journal of Supercritical Fluids ; Volume 109 , 2016 , Pages 166-176 ; 08968446 (ISSN) Noroozi, J ; Ghotbi, C ; Jahanbin Sardroodi, J ; Karimi Sabet, J ; Robert, M. A ; Sharif University of Technology
    Elsevier  2016
    Abstract
    Classical molecular dynamics simulations are used to compute the solvation free energy of two pharmaceutical solids, namely ibuprofen and acetaminophen in carbon dioxide (CO2), over the density range of interest in supercritical processes. In order to examine the influence of the solvent model on the resulting free energies, three popular CO2 models (Zhang, EPM2, and TraPPE) are studied. Relatively large discrepancies for the solvation free energy exist between these CO2 models, suggesting that the former is sensitive to the different balances between dispersive and electrostatic forces used in these models. In particular, for the solvation of the highly polar (dipole moment of ∼5.2 Debye)...