Cerdà Juan J, Sintes Tomás, Toral Raúl
Institute for Computational Physics, Universität Stuttgart, 70569 Stuttgart, Germany.
J Chem Phys. 2009 Oct 7;131(13):134901. doi: 10.1063/1.3238568.
We present an extensive numerical study on the behavior of spherical brushes confined into a spherical cavity. Self-consistent field (SCF) and off-lattice Monte Carlo (MC) techniques are used in order to determine the monomer and end-chain density profiles and the cavity pressure as a function of the brush properties. A comparison of the results obtained via SCF, MC, and the Flory theory for polymer solutions reveals SCF calculations to be a valuable alternative to MC simulations in the case of free and softly compressed brushes, while the Flory's theory accounts remarkably well for the pressure in the strongly compressed regime. In the range of high compressions, we have found the cavity pressure P to follow a scale relationship with the monomer volume fraction v, P approximately v(alpha). SCF calculations give alpha=2.15+/-0.05, whereas MC simulations lead to alpha=2.73+/-0.04. The underestimation of alpha by the SCF method is explained in terms of the inappropriate account of the monomer density correlations when a mean field approach is used.
我们对限制在球形腔内的球形刷的行为进行了广泛的数值研究。使用自洽场（SCF）和非晶格蒙特卡罗（MC）技术来确定单体和端链密度分布以及作为刷特性函数的腔压力。通过SCF、MC和聚合物溶液的弗洛里理论获得的结果比较表明，在自由和软压缩刷的情况下，SCF计算是MC模拟的一种有价值的替代方法，而弗洛里理论在强压缩区域对压力的解释非常好。在高压缩范围内，我们发现腔压力P与单体体积分数v遵循比例关系，P约为v(α)。SCF计算得出α = 2.15 ± 0.05，而MC模拟得出α = 2.73 ± 0.04。SCF方法对α的低估是由于使用平均场方法时对单体密度相关性的不当考虑。
