A molecular simulation study of cavity size distributions and diffusion in para and meta isomers

Molecular simulation study of penetrant gas transport properties into the pure and nanosized silica particles filled polysulfone membranes

“…Another parameter which is related to the cavity properties is the fractional cavity volume (FCV) of the membranes which enhances by adding silica nanoparticles to the pure polymeric membranes. As can be seen from the experimental method of PALS and CESA method are 5.62 and 3.7 Å, respectively [66,73]. Comparing the results indicates that the simulation results are in close agreement with the experimental results and this confirms that the MD simulation is a reliable method for calculating the ACS of membranes.…”

“…2(a)) with the cell length around 20.357 0.22 Å and the equilibrium density approximately 1.22 70.02 g/cm 3 (the experimental density value of PSF is 1.24 g/cm 3 ) was obtained. In a previous study by Wang et al [66], the amorphous cell contained one chain of PSF with 20 repeating units and the simulation cell length was around 18.1 Å which is in agreement with the cell length used in this study [66]. The structure of the nanocomposite membranes used in this study includes the polymer chains and the nanoparticles and to simulate the membranes especially the PSF/nonporous, nanosized silica membranes, it is necessary to construct the silica nanoparticles by the simulation software and embedding them with the polymer chain in the amorphous cell.…”

“…In MD simulation, the diffusion coefficient for the penetrant is calculated by means of the Einstein relationship [18,55,66,[68][69][70].…”

Diffusion behavior of benzene/cyclohexane molecules in poly(vinyl alcohol)-graphite hybrid membranes by molecular dynamics simulation

“…It can be seen that diffusion coefficients have an exponential relation to the inverse FFV, which agrees well with the commonemployed free volume theory (Cohen and Turnbull, 1959;Wang et al, 2005). In addition, the B value for benzene in Fig.…”

Free volume and polymeric structure analyses of aromatic polyamide membranes: A molecular simulation and experimental study

“…To improve the membrane performance and selectivity, a suitable material and membrane fabrication conditions must be chosen. Thus, many researchers have focused on optimizing the tradeoff between the permeation rate and selectivity for separation or purification processes [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16]. Past studies have also reported that the addition of bulky CF 3 groups in a polymer structure results in a higher free volume in a dense membrane, yielding good gas permeability and selectivity [6,[17][18][19][20].…”