화학공학소재연구정보센터
Polymer, Vol.48, No.3, 877-886, 2007
Phase behavior of an amphiphilic molecule in the presence of two solvents by dissipative particle dynamics
We examine the phase behavior of A(m)B(n) amphiphilic molecules in the presence of two solvents X-2 and Y-2, which are strongly selective for A and B, respectively, by dissipative particle dynamics (DPD). We find that increasing the immiscibility parameter between the two solvents not only drives a macrophase separation into two phases X-2-rich and Y-2-rich for systems at less concentrated regimes, but also expands the ordered microphase region at more concentrated regimes. It even induces a sequential transition of various ordered structures. This is not surprising since increasing the solvent immiscibility parameter enhances the preferentiality Of X-2 for A and Y-2 for B, and thus qualitatively varies the degree of molecular asymmetry in the amphiphilic molecules. In general, our current results reveal that the DPD simulation method has successfully captured the phase separation behavior of an amphiphilic molecule in the presence of two solvents. However, we find that the packing order of the spherical micelles is greatly affected by the finite size of the Simulation box. As Such, it becomes difficult to examine the most stable packing array of spheres via the DPD method. Still, DPD reveals a possible spherical order of A15, which has been observed ill some amphiphilic molecule systems. (c) 2007 Elsevier Ltd. All rights reserved.