Investigation on the membrane formation process of polymer–diluent system via thermally induced phase separation accompanied with mass transfer across the interface: Dissipative particle dynamics simulation and its experimental verification

Tang, Yuanhui; He, Yandong; Wang, Xiaolin

doi:10.1016/j.memsci.2014.09.034

Cited by 37 publications

(11 citation statements)

References 25 publications

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“…The diagnostics include the mean square displacement (MSD), the radius of gyration (R g ), the radial density distribution ( g(r)) and the structure factor (S(k)). The MSD can be acknowledged as a more effective parameter to characterize the average motion velocity of particles compared with the diffusion coefficient and it can be calculated using 26,27…”

Section: Resultsmentioning

confidence: 99%

Chain conformation and dynamics in ultrahigh molecular weight polyethylene melts undergoing extensional–shear coupled flow: insight from dissipative particle dynamics simulation

Wang

Chen

Cao

et al. 2020

Polymer International

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A first attempt is made to present a detailed mesoscopic-level description of the conformation and equilibrium dynamic properties of macromolecular chains in ultrahigh molecular weight polyethylene/polypropylene blends driven by extensiondominated coupled flow, in comparison with shear-dominated coupled flow. Extension-dominated coupled flow can be defined as _ γ = 0.005, _ ε ≥ 0.1 and shear-dominated coupled flow as _ ε = 0.1, _ γ ≥ 1, as verified by the time-dependent evolution tendency of cell parameters and velocity profiles along the x, y, z directions. In the case of extension-dominated coupled flow, the chains are greatly elongated and prefer to align along the flow direction, where the polypropylene chains appear to form a somewhat uniform layer. By comparison, the macromolecular chains assume a highly collapsed conformation and have a greater preference to align themselves perpendicular to the flow direction under shear-dominated coupled flow, which can be ascribed to the rapid diffusion of polymer chains and a minor role of the weak van de Waals interaction in structural transitions. Analyses of conformational behavior derived from dissipative particle dynamics trajectories can, in general, serve as a useful guideline for experimental investigations of ultrahigh molecular weight polyethylene based materials prepared by eccentric rotor extrusion.

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Section: Resultsmentioning

confidence: 99%

Chain conformation and dynamics in ultrahigh molecular weight polyethylene melts undergoing extensional–shear coupled flow: insight from dissipative particle dynamics simulation

Wang

Chen

Cao

et al. 2020

Polymer International

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“…To shed more light onto the morphology and alignment behavior corresponding to extensional–shear coupled flow, we plot the mean square displacement (MSD) of PA6 as a function of simulation time for different coupled rates in Figure 7, as well as shear rates and extensional rates. MSD can be acknowledged as more effective parameter to characterize the average motion velocity of particles compared with the diffusion coefficient and it is calculated by Equation (14) [30,31]:MSD=〈|truer→false(tfalse)−truer→false(0false)|2〉 where truer→false(tfalse) and truer→false(0false) refer to the coordinate of a particle at time t and 0, respectively. The slope of the MSD-time curve represents the intensity of activity in polymer chains (or beads).…”

Section: Resultsmentioning

confidence: 99%

A Dissipative Particle Dynamics Study of Flow Behaviors in Ultra High Molecular Weight Polyethylene/Polyamide 6 Blends Based on Souza-Martins Method

Wang

Cao

et al. 2019

Polymers

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This paper presents our study on the use of dissipative particle dynamics (DPD) simulations to discover the flow behavior in ultra high molecular weight polyethylene/polyamide 6 (UHMWPE/PA6) blends associated with extensional-shear coupled flow, based on the Souza-Martins method, for the first time. By way of simulations, we aimed at investigating the mesoscopic morphology and alignment behavior in response to extensional-shear coupled flow, in comparison with simple shear flow and simple extensional flow. Our results reveal that the aggregation of polymers is noticeable under zero flow, as expected. Within the considered range of extensional-shear coupled rates, the morphology transforms from micelle-like clusters to a chain-like network structure by increasing coupled rates from 0.01 to 2.0. Furthermore, it shows a linear distribution along the flow direction at a high coupled rate. It can be concluded that the flow behaviors in UHMWPE/PA6 blends are significantly impacted by extensional-shear coupled rates. The orientation behavior induced by extensional-shear coupled flow is more obvious than shear flow, even though flow variations and mass fractions yield less effects on the distribution behaviors of UHMWPE/PA6 blends. The DPD results are verified by mean square displacement (MSD) as a function of simulation time and relative concentration distribution along Z direction.

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“…The N‐TIPS method was recently studied theoretically using the dissipative particle dynamics simulation by Tang et al which confirmed the effects of coagulation bath temperature and the polymer–solvent interaction on skin formation kinetics.…”

Section: Thermally Induced Phase Separationmentioning

confidence: 90%

“…For instance, the binodal curve shifts to higher temperature with decreasing compatibility, and vice versa. The solvent–polymer compatibility can be semiquantitatively approximated using the solubility parameter …”

Section: Thermally Induced Phase Separationmentioning

confidence: 99%

Thermally induced phase separation and electrospinning methods for emerging membrane applications: A review

et al. 2015

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In this review, thermally induced phase separation (TIPS) and electrospinning methods for preparation of fluoropolymer membranes are assessed, particularly for the polyvinylidene fluoride (PVDF) and polyethylene chlorotrifluoroethylene membranes. This review focuses on controlling the membrane morphology from the thermodynamic and kinetic perspectives to understand the relationship between the membrane morphology and fabrication parameters. In addition, the current status of the nonsolvent induced phase separation (NIPS) method and the combined NIPS-TIPS (N-TIPS) method, which is a new emerging fabrication method, are discussed. The past literature data are compiled and an upperbound curve (permeability vs. tensile strength) is proposed for the TIPS-prepared PVDF membranes. Furthermore, the key parameters that control and determine the membrane morphology when using the electrospinning method are reviewed. Exploiting the unique advantages of the electrospinning method, our current understanding in controlling and finetuning the PVDF crystal polymorphism (i.e., b-phase) is critically assessed. V C 2015 American Institute of Chemical Engineers AIChE J, 62: 461-490, 2016 Figure 15. Cross section of 40 wt % PVDF/GBL hollow fiber membranes: (left) with LiCl additive, (middle) with glycerol additive, (right) with LiCl and glycerol additives.Formation of such fine pores nearly doubled the flux without losing mechanical strength. 28 481 TEM images of 4 wt % PVP nanofibers from different compositions of EtOH/DMF: (b) 65/35, (c) 50/50, (d) 35/65, and (e) SEM image of 4 wt % PVP nanofibers using EtOH/DMF (50/50). 146 482

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Investigation on the membrane formation process of polymer–diluent system via thermally induced phase separation accompanied with mass transfer across the interface: Dissipative particle dynamics simulation and its experimental verification

Cited by 37 publications

References 25 publications

Chain conformation and dynamics in ultrahigh molecular weight polyethylene melts undergoing extensional–shear coupled flow: insight from dissipative particle dynamics simulation

Chain conformation and dynamics in ultrahigh molecular weight polyethylene melts undergoing extensional–shear coupled flow: insight from dissipative particle dynamics simulation

A Dissipative Particle Dynamics Study of Flow Behaviors in Ultra High Molecular Weight Polyethylene/Polyamide 6 Blends Based on Souza-Martins Method

Thermally induced phase separation and electrospinning methods for emerging membrane applications: A review

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