Polymer adsorption on a fractal substrate: Numerical study

Blavatska, V.; Janke, Wolfhard

doi:10.1063/1.3691102

Cited by 11 publications

(9 citation statements)

References 68 publications

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“…To clarify the conception of these two shape descriptors in our results, the value of κ 2 for a doublet and a triplet with particles sat on the corners of an equilateral triangle is 1.0 and 0.25, respectively, and the value of b / R g 2 is 1.0 and 0.29. For a planar conformation, − this parameter approaches 0.25. According to Figure , one can see the same plateaus in the shape descriptors of the formed aggregates as what were observed in the plots of their size and gyration radius, depicted in Figure .…”

Section: Resultsmentioning

confidence: 97%

Asphaltene Mesoscale Aggregation Behavior in Organic Solvents—A Brownian Dynamics Study

Ahmadi

Abedi

2018

J. Phys. Chem. B

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Significant advances have been achieved in understanding the main molecular mechanisms leading to asphaltene aggregation. However, the existing computational deficiency of molecular dynamics simulations did not allow full reproduction of the complex aggregation behavior of asphaltene in the past. In this work, we use the Brownian dynamics simulation to investigate asphaltene aggregation behavior on larger length and time scales that have not been previously accessed by molecular simulations. This enabled us to completely render the formation of clusters of asphaltene nanoaggregates and the resulting fractal or network of aggregates during the aggregation process. Asphaltene aggregation is studied at several volume fractions (ϕ = 1-7%) of asphaltene nanoaggregates in two solvents including heptane and heptol (i.e., a mixture of heptane and toluene). Our simulation results support the aggregation hierarchy proposed in the Yen-Mullins model (Mullins, Annu. Rev. Anal. Chem. 2011, 4, 393-418.) by demonstrating that asphaltene nanoaggregates form small clusters with an aggregation number of 7-8 and an average gyration radius of ∼4.0 nm capable of forming either fractal aggregates with a fractal dimension of 1.93-2.04 at low ϕ or percolating networks of aggregates at high ϕ. Percolating structures are observed at ϕ = 7% in both solvents. In heptol, the structures mainly percolate along two directions, whereas in heptane, they can percolate along three directions (i.e., x, y, and z). The self-diffusion coefficient ( D) significantly decreases as ϕ increases. Generally, D is larger in heptol than in heptane, but this difference diminishes as ϕ increases, approaching to almost the same value at ϕ = 7%.

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Section: Resultsmentioning

confidence: 97%

Asphaltene Mesoscale Aggregation Behavior in Organic Solvents—A Brownian Dynamics Study

Ahmadi

Abedi

2018

J. Phys. Chem. B

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“…For planar symmetric objects, the relative shape anisotropy converges to the value of 1/4. [36][37][38][39][40] The last descriptor, the asphericity parameter b, measures the deviation from the spherical symmetry (recall that λ 1 is the largest eigenvalue):…”

Section: B Observablesmentioning

confidence: 99%

Gyration tensor based analysis of the shapes of polymer chains in an attractive spherical cage

Arkin

Janke

2013

The Journal of Chemical Physics

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115

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In a recent computational study, we found highly structured conformations for the polymer-attractive sphere model system. Those conformations are of highly ordered spherical shape or form two-dimensional planar, compact to extended, random coil structures. The observed conformations range from desorbed to partially or even completely adsorbed. In order to present their shape characteristics, here we calculate the gyration tensor and related shape descriptors.

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“…Combining the mean-field theory and MC, Chakraborty and co-workers , found that a transition from a weak to a strong adsorption regime may occur when statistical patterns of heteropolymers and the heterogeneous substrate are related in a specific way. Besides, surfaces found in nature might not have necessarily random or pattern distributions of chemical species but instead be fractal. , Several works studied the influence of nontrivial surface geometries on polymer adsorption employing lattice-based models. − For instance, Blavatska and Janke investigated the adsorption transition of an end-grafted flexible polymer on a percolation cluster formed by a substrate with the fraction of the attractive sites at the percolation threshold. The authors revealed that the critical quantities characterizing the adsorption transition, that is, the crossover exponent and the critical adsorption temperature, for the fractal surface differ from the ones of the attractive homogeneous surface.…”

Section: Introductionmentioning

confidence: 99%

Adsorption and Desorption of Polymers on Bioinspired Chemically Structured Substrates

Morozova

García

Barrat

et al. 2021

ACS Appl. Mater. Interfaces

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Natural biological surfaces exhibit interesting properties due to their inhomogeneous chemical and physical structure at the micro-and nanoscale. In the case of hair or skin, this also influences how waterborne macromolecules ingredients will adsorb and form cosmetically performing deposits (i.e., shampoos, cleansers, etc.). Here, we study the adsorption of hydrophilic flexible homopolymers on heterogeneous, chemically patterned substrates that represent the surface of the hair by employing coarse-grained molecular dynamics simulations. We develop a method in which the experimental images of the substrate are used to obtain information about the surface properties. We investigate the polymer adsorption as a function of polymer chain length and polymer concentration spanning both dilute and semidilute regimes. Adsorbed structures are quantified in terms of trains, loops, and tails. We show that upon increasing polymer concentration, the length of tails and loops increases at the cost of monomers belonging to trains. Furthermore, using an effective description, we probe the stability of the resulting adsorbed structures under a linear shear flow. Our work is a first step toward developing models of complex macromolecules interacting with realistic biological surfaces, as needed for the development of more ecofriendly industrial products.

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Polymer adsorption on a fractal substrate: Numerical study

Cited by 11 publications

References 68 publications

Asphaltene Mesoscale Aggregation Behavior in Organic Solvents—A Brownian Dynamics Study

Asphaltene Mesoscale Aggregation Behavior in Organic Solvents—A Brownian Dynamics Study

Gyration tensor based analysis of the shapes of polymer chains in an attractive spherical cage

Adsorption and Desorption of Polymers on Bioinspired Chemically Structured Substrates

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