Effect of elongational flow on immiscible polymer blend/nanoparticle composites: a molecular dynamics study

Abstract

Using coarse-grained nonequilibrium molecular dynamics, the dynamics of a blend of the equal ratio of immiscible polymers mixed with nanoparticles (NP) are simulated. The simulations are conducted under planar elongational flow, which affects the dispersion of the NPs and the self-assembly morphology. The goal of this study is to investigate the effect of planar elongational flow on the nanocomposite blend system as well as to thoroughly compare the blend to an analogous symmetric block copolymer (BCP) system to understand the role of the polymer structure on the morphology and NP dispersion. Two types of spherical NPs are considered: (1) selective NPs that are attracted to one of the polymer components and (2) nonselective NPs that are neutral to both components. A comparison of the blend and BCP systems reveals that for selective NP, the blend system shows a much broader NP distribution in the selective phase than the BCP phase. This is due to a more uniform distribution of polymer chain ends throughout the selective phase in the blend system than the BCP system. For nonselective NP, the blend and BCP systems show similar results for low elongation rates, but the NP peak in the BCP system broadens as elongation rates approach the order-disorder transition. In addition, the presence of NP is found to affect the morphology transitions of both the blend and BCP systems, depending on the NP type.

Shear-Induced Microscopic Structure Damage in Polymer Nanocomposites: A Dynamic Density Functional Theoretical Study

“…Under the interaction region from ε np = 1.0ε pp to 4.0ε pp , the particles display several layers to form sandwich-like structure, depending upon both the shear flow and particle−polymer interaction. Such ordered structure has also been reported in previous simulation 17 and experiment. 54 With the increase of the interaction strength, the number of layers slightly decreases, but the distance between the adjacent layers increases.…”

“…Molecular dynamic simulations and statistical mechanic theories provide reliable methods to yield microscopic insights into the diffusion of particles in polymer systems under various shear conditions. In some simulations, the influences of shear flow on particle dispersion states were clearly displayed via particle coordinates. − It was shown that a suitable shear strength can result in particle aggregation, sandwich-like structure formation, and homogeneous particle dispersion in polymer matrix with an increase of particle–polymer interaction . A shear field also played an important role in particle distribution in the cases of symmetric block copolymers but had little effect on the immiscible polymer blend/particle composites .…”

“…In some simulations, the influences of shear flow on particle dispersion states were clearly displayed via particle coordinates. − It was shown that a suitable shear strength can result in particle aggregation, sandwich-like structure formation, and homogeneous particle dispersion in polymer matrix with an increase of particle–polymer interaction . A shear field also played an important role in particle distribution in the cases of symmetric block copolymers but had little effect on the immiscible polymer blend/particle composites . In a Brownian suspension, shear thickening resulted in a transition of particle flow from lubricated near-contacting to frictionally contacting. , However, these simulations are computationally intensive; thus, only a few parameters were considered.…”

“…19 A shear field also played an important role in particle distribution in the cases of symmetric block copolymers but had little effect on the immiscible polymer blend/particle composites. 17 In a Brownian suspension, shear thickening resulted in a transition of particle flow from lubricated near-contacting to frictionally contacting. 20,21 However, these simulations are computationally intensive; thus, only a few parameters were considered.…”

Phase transition of a diblock copolymer and homopolymer hybrid system induced by different properties of nanorods

“…For many practical applications, the addition of nanoparticles has been considered as an effective route to material improvement and an important method for creating highly ordered structures. [12][13][14][15][16] In particular, the addition of anisotropic nanoparticles (such as nanorods) to polymeric materials can be beneficial and increase their photoelectric characteristics, optical properties and mechanical properties. [17][18][19][20][21][22][23] The nanorods of noble metals (such as gold) and semiconductors (such as CdSe) possess interesting photoelectrical properties and can significantly improve the efficiency of polymer photovoltaic devices by enhancing their carrier mobilities.…”