Gupta Supriya, Chokshi Paresh
Department of Chemical Engineering, Indian Institute of Technology Delhi, New Delhi 110 016, India.
Soft Matter. 2020 Apr 8;16(14):3522-3535. doi: 10.1039/d0sm00124d.
Geometrical confinement plays an important role in generating novel molecular organization arising out of structural frustration and confinement-induced entropy loss. In the present study, we perform self-consistent mean-field theoretical calculations to examine a mixture of a diblock copolymer and polymer grafted nanoparticles confined in a cylindrical nanopore. The two-dimensional analysis is aimed at constructing the equilibrium nanostructures decorated with particles in an ordered manner. The rich variety of ordered mesophases of the diblock copolymer under confinement provide a template to achieve the self-assembly of nanoparticles in a selective domain. The localization behavior of nanoparticles under confinement is found to be qualitatively different from that in a bulk system. In particular, for the concentric lamellar phase the particles tend to localize predominantly in the region of greater curvature within the curved lamella. The incorporation of grafted nanoparticles also results in a transition in ordered phases. Various equilibrium morphologies are observed depending upon the degree of confinement, particle loading, density of grafted segments and selectivity of the particle core to the polymeric species. The ordering of particles and the ensuing equilibrium nanostructures are analyzed. The comprehensive understanding of the self-assembly behavior of particles enables one to design novel nanomaterials with desirable material properties.
几何限制在因结构受挫和限制诱导的熵损失而产生的新型分子组织形成过程中起着重要作用。在本研究中，我们进行了自洽平均场理论计算，以研究限制在圆柱形纳米孔中的二嵌段共聚物和聚合物接枝纳米粒子的混合物。二维分析旨在构建有序排列有粒子的平衡纳米结构。受限条件下二嵌段共聚物丰富多样的有序中间相为在选择性区域实现纳米粒子的自组装提供了模板。发现纳米粒子在受限条件下的定位行为与本体系统中的定性不同。特别是，对于同心层状相，粒子倾向于主要定位在弯曲层内曲率较大的区域。接枝纳米粒子的加入也导致有序相的转变。根据限制程度、粒子负载量、接枝链段密度以及粒子核与聚合物种类的选择性，观察到了各种平衡形态。分析了粒子的排列以及随之产生的平衡纳米结构。对粒子自组装行为的全面理解使人们能够设计具有所需材料特性的新型纳米材料。
