Roy Supriya, Chen Yeng-Long
Institute of Physics, Academia Sinica, Taipei, Taiwan.
J Chem Phys. 2021 Jan 14;154(2):024901. doi: 10.1063/5.0034602.
We investigate the rich phase behavior of strongly confined semi-flexible (SFC) polymer-nanoparticle (NP) systems using the graphics processing unit accelerated Langevin dynamics simulation. Hard nanoparticles (HNP) that repel each other and ideal nanoparticles (INP) that do not interact with the same species are used as model additives to a strongly confined semiflexible polymer fluid. Both types of NPs exclude the monomer beads in the same way, but they have qualitatively different effects on the SFC isotropic-nematic (I-N) transition. For the total volume fraction ϕ < 0.16, adding a low volume fraction of HNPs (ϕ) disrupts the long range nematic order of the polymers, whereas adding HNPs in a moderately packed system (0.16 < ϕ < 0.32) facilitates polymer alignment due to the restricted polymer orientational degree of freedom. For dense packing (ϕ > 0.32), polymers and NPs separate into layers along the slit height and the NPs form crystalline microdomains. In contrast, INP additives always promote inter-polymer alignment for low to moderate monomer volume fractions (ϕ). Furthermore, we found that INPs form a droplet-like fluid domain in dense nematic polymer systems.
我们使用图形处理单元加速的朗之万动力学模拟，研究了强受限半柔性（SFC）聚合物-纳米颗粒（NP）系统丰富的相行为。将相互排斥的硬纳米颗粒（HNP）和不与同种物质相互作用的理想纳米颗粒（INP）用作强受限半柔性聚合物流体的模型添加剂。两种类型的NP以相同方式排除单体珠，但它们对SFC各向同性-向列相（I-N）转变具有质的不同影响。对于总体积分数ϕ<0.16，添加低体积分数的HNP（ϕ）会破坏聚合物的长程向列相序，而在中等堆积系统（0.16<ϕ<0.32）中添加HNP由于聚合物取向自由度受限而促进聚合物排列。对于密集堆积（ϕ>0.32），聚合物和NP沿狭缝高度分层，并且NP形成晶体微区。相比之下，对于低至中等单体体积分数（ϕ），INP添加剂总是促进聚合物间排列。此外，我们发现INP在密集向列相聚合物系统中形成液滴状流体域。
