Impact of pore distribution characteristics on percolation threshold based on site percolation theory

Huang, Xudong; Yang, Dinglong; Kang, Zhiqin

doi:10.1016/j.physa.2021.125800

Cited by 14 publications

(4 citation statements)

References 54 publications

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“…The value of c l * ≈ 0.3 is consistent with the simulation results of the site percolation threshold of the sc lattice. 49,50 Below c l * , the mean size of large-NP aggregates is very small as it is less than 2.5, indicating that the large-NP aggregates in the system are separated by small NPs. It is known that a polymer chain has more chance to be trapped on the large-NP aggregates during its diffusion.…”

Section: Resultsmentioning

confidence: 95%

“…For c l = 0.5, clusters of large NPs may form connected clusters since c l = 0.5 is above the percolation threshold c l * E 0.3. 49,50 As b = 1 at large PD, the polymer chain diffuses along paths formed by large NPs. Thus one can imagine that, at large PD, the diffusion of the polymer chain will not be changed if we remove all small NPs or set all small NPs to be repulsive.…”

Section: Orderly Distributed Npsmentioning

confidence: 99%

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Simulation study on the effect of polydisperse nanoparticles on polymer diffusion in crowded environments

Hua,

Luo

2023

Phys. Chem. Chem. Phys.

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Section: Resultsmentioning

confidence: 95%

Section: Orderly Distributed Npsmentioning

confidence: 99%

Simulation study on the effect of polydisperse nanoparticles on polymer diffusion in crowded environments

Hua,

Luo

2023

Phys. Chem. Chem. Phys.

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“…This indicates that the binary gel lacks a highly structured matrix due to the low degree of polymer swelling and factors such as drug diffusion, mesh size, and erosion would then not be limiting factors to drug release [ 46 ]. Percolation theory is also unsuitable for explaining the drug release of the binary gel owing to the extremely low porosity and lack of connectivity and permeability [ 45 , 47 , 48 ], indicating that more complex processes such as drug–matrix interactions are influencing the release of the drug. Alternatively, one more explanation for the slow release could be due to the shear-thinning properties that made the gels in the dialysis bags extremely viscous at static conditions, thus impeding drug diffusion and erosion of the gel.…”

Section: Discussionmentioning

confidence: 99%

Hydroxypropyl Methylcellulose Bioadhesive Hydrogels for Topical Application and Sustained Drug Release: The Effect of Polyvinylpyrrolidone on the Physicomechanical Properties of Hydrogel

Pan,

Svirskis,

Waterhouse

et al. 2023

Pharmaceutics

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Hydrogels are homogeneous three-dimensional polymeric networks capable of holding large amounts of water and are widely used in topical formulations. Herein, the physicomechanical, rheological, bioadhesive, and drug-release properties of hydrogels containing hydroxypropyl methylcellulose (HPMC) and polyvinylpyrrolidone (PVP) were examined, and the intermolecular interactions between the polymers were explored. A three-level factorial design was used to form HPMC–PVP binary hydrogels. The physicomechanical properties of the binary hydrogels alongside the homopolymeric HPMC hydrogels were characterized using a texture analyzer. Rheological properties of the gels were studied using a cone and plate rheometer. The bioadhesiveness of selected binary hydrogels was tested on porcine skin. Hydrophilic benzophenone-4 was loaded into both homopolymeric and binary gels, and drug-release profiles were investigated over 24 h at 33 °C. Fourier transform infrared spectroscopy (FTIR) was used to understand the inter-molecular drug–gel interactions. Factorial design analysis supported the dominant role of the HPMC in determining the gel properties, rather than the PVP, with the effect of both polymer concentrations being non-linear. The addition of PVP to the HPMC gels improved adhesiveness without significantly affecting other properties such as hardness, shear-thinning feature, and viscosity, thereby improving bioadhesiveness for sustained skin retention without negatively impacting cosmetic acceptability or ease of use. The release of benzophenone-4 in the HPMC hydrogels followed zero-order kinetics, with benzophenone-4 release being significantly retarded by the presence of PVP, likely due to intermolecular interactions between the drug and the PVP polymer, as confirmed by the FTIR. The HPMC–PVP binary hydrogels demonstrate strong bioadhesiveness resulting from the addition of PVP with desirable shear-thinning properties that allow the formulation to have extended skin-retention times. The developed HPMC–PVP binary hydrogel is a promising sustained-release platform for topical drug delivery.

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“…The percolation threshold in continuum percolation theory [1][2][3] plays a significant role in thin film growth [4], grain boundary engineering [5,6], and research on porous media [7,8]. In the formation of a thin film from a random distribution of initially isolated grains on a substrate, we identify the percolation threshold with the instant when the grains form a cluster that connects two opposing edges of the substrate.…”

Section: Introductionmentioning

confidence: 99%

Formation and morphology of closed and porous films grown from grains seeded on substrates: Two-dimensional simulations

Janssens,

Vázquez-Cortés,

Fried

2021

Preprint

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Two-dimensional simulations are used to explore topological transitions that occur during the formation of films grown from grains that are seeded on substrates. This is done for a relatively large range of the initial value Φ s of the grain surface fraction Φ. The morphology of porous films is captured at the transition when grains connect to form a one-component network using newly developed raster-free algorithms that combine computational geometry and network theory. Further insight on the morphology of porous films and their suspended counterparts is obtained by studying the pore surface fraction Φ p , the pore over grain ratio, the pore area distribution, and the contribution of pores of certain chosen areas to Φ p . Pinhole survival is evaluated at the transition when film closure occurs using survival function estimates. The morphology of closed films (Φ = 1) is also characterized and is quantified by measuring grain areas and perimeters. The majority of investigated quantities are found to depend sensitively on Φ s and the long-time persistence of pinholes exhibits critical behavior as a function of Φ s . In addition to providing guidelines for designing effective processes for manufacturing thin films and suspended porous films with tailored properties, this work may advance the understanding of continuum percolation theory.

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Impact of pore distribution characteristics on percolation threshold based on site percolation theory

Cited by 14 publications

References 54 publications

Simulation study on the effect of polydisperse nanoparticles on polymer diffusion in crowded environments

Simulation study on the effect of polydisperse nanoparticles on polymer diffusion in crowded environments

Hydroxypropyl Methylcellulose Bioadhesive Hydrogels for Topical Application and Sustained Drug Release: The Effect of Polyvinylpyrrolidone on the Physicomechanical Properties of Hydrogel

Formation and morphology of closed and porous films grown from grains seeded on substrates: Two-dimensional simulations

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