In this article,we apply classical density functional theory to investigate the characteristics of depletion interaction in Lennard-Jones(LJ)binary fluid mixtures.First,to confirm the validity of our adopted density functional formalism,we calculate the radial distribution functions using a theoretical approach and compare them with results obtained by molecular dynamics simulation.Then,this approach is applied to two colloids immersed in U solvent systems.We investigate the variation of depletion interaction with respect to the distance of two colloids in LJ binary systems.We find that depletion interaction may be attractive or repulsive,mostly depending on the bulk density of the solvent and the temperature of the binary system.For high bulk densities,the repulsive barrier of depletion force is remarkable when the total excluded volume of colloids touches each other and reaches a maximum.The height of the repulsive barrier is related to the parameters of the LJ potential and bulk density.Moreover,the depletion force may exhibit attractive wells if the bulk density of the solvent is low.The attractive well tends to appear when the surface-surface distance of colloids is half of the size of the polymer and deepens with temperature lowering in a fixed bulk density.In contrast with the hard-sphere system,no oscillation of depletion potential around zero is observed.

CAS Key Laboratory of Theoretical Physics,Institute of Theoretical Physics,Chinese Academy of Sciences,Beijing 100190,China;School of Physical Sciences,University of Chinese Academy of Sciences,Beijing 100049,China;State Key Laboratory of Multiphase Complex Systems,Institute of Process Engineering,Chinese Academy of Sciences,Beijing 100190,China;School of Systems Science,Beijing Normal University,Beijing 100875,China

[1]Yue Chen;Wei Chen;Xiaosong Chen-.A classical density functional approach to depletion interaction of Lennard-Jones binary mixtures)[J].理论物理,2022(03):87-96

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