TY - JOUR

T1 - Free energy landscapes and volumes of coexisting phases for a colloidal dispersion

AU - Lang, Trinh Hoa

AU - Wang, G. F.

AU - Lai, S. K.

N1 - Funding Information:
This work was supported by the National Science Council, Taiwan (Grant No. NSC96-2112-M-008-018-MY3).

PY - 2010

Y1 - 2010

N2 - Treating the repulsive part of a pairwise potential by the hard-sphere form and its attractive part by the effective depletion potential form, we calculate using this model potential the colloidal domains of phase separation. Differing from the usual recipe of applying the thermodynamic conditions of equal pressure and equal chemical potential where the branches of coexisting phases are the ultimate target, we employ the free energy density minimization approach [G. F. Wang and S. K. Lai, Phys. Rev. E 70, 051402 (2004)] to crosshatch the domains of equilibrium phases, which consist of the gas, liquid, and solid homogeneous phases as well as the coexistence of these phases. This numerical procedure is attractive since it yields naturally the colloidal volume of space occupied by each of the coexisting phases. In this work, we first examine the change in structures of the fluid and solid free energy density landscapes with the effective polymer concentration. We show by explicit illustration the link between the free energy density landscapes and the development of both the metastable and stable coexisting phases. Then, attention is paid to the spatial volumes predicted at the triple point. It is found here that the volumes of spaces of the three coexisting phases at the triple point vary one dimensionally, whereas for the two coexisting phases, they are uniquely determined.

AB - Treating the repulsive part of a pairwise potential by the hard-sphere form and its attractive part by the effective depletion potential form, we calculate using this model potential the colloidal domains of phase separation. Differing from the usual recipe of applying the thermodynamic conditions of equal pressure and equal chemical potential where the branches of coexisting phases are the ultimate target, we employ the free energy density minimization approach [G. F. Wang and S. K. Lai, Phys. Rev. E 70, 051402 (2004)] to crosshatch the domains of equilibrium phases, which consist of the gas, liquid, and solid homogeneous phases as well as the coexistence of these phases. This numerical procedure is attractive since it yields naturally the colloidal volume of space occupied by each of the coexisting phases. In this work, we first examine the change in structures of the fluid and solid free energy density landscapes with the effective polymer concentration. We show by explicit illustration the link between the free energy density landscapes and the development of both the metastable and stable coexisting phases. Then, attention is paid to the spatial volumes predicted at the triple point. It is found here that the volumes of spaces of the three coexisting phases at the triple point vary one dimensionally, whereas for the two coexisting phases, they are uniquely determined.

UR - http://www.scopus.com/inward/record.url?scp=74549179082&partnerID=8YFLogxK

U2 - 10.1063/1.3285267

DO - 10.1063/1.3285267

M3 - 期刊論文

C2 - 20095712

AN - SCOPUS:74549179082

VL - 132

JO - Journal of Chemical Physics

JF - Journal of Chemical Physics

SN - 0021-9606

IS - 2

M1 - 024910

ER -