Polymer melts and polymer solutions near patterned surfaces

Seok, Chaok; Freed, Karl F.; Szleifer, Igal

doi:10.1063/1.481206

Cited by 22 publications

(22 citation statements)

References 35 publications

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“…The theory describes the adsorption process from the bulk solution to the surface, including a detailed description of the region in the vicinity of the surface. Further, although the theory was presented here assuming that the only inhomogeneous direction is that perpendicular to the surface, it can be easily extended to treat inhomogeneous three-dimensional systems (Seok et al 2000). The theory enables the study of the changes of the structure of the adsorbed layer, with molecular detail, as a function of time.…”

Section: Discussionmentioning

confidence: 99%

Kinetics and Thermodynamics of Protein Adsorption: A Generalized Molecular Theoretical Approach

Fang

Szleifer

2001

Biophysical Journal

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154

169

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The thermodynamics and kinetics of protein adsorption are studied using a molecular theoretical approach. The cases studied include competitive adsorption from mixtures and the effect of conformational changes upon adsorption. The kinetic theory is based on a generalized diffusion equation in which the driving force for motion is the gradient of chemical potentials of the proteins. The time-dependent chemical potentials, as well as the equilibrium behavior of the system, are obtained using a molecular mean-field theory. The theory provides, within the same theoretical formulation, the diffusion and the kinetic (activated) controlled regimes. By separation of ideal and nonideal contributions to the chemical potential, the equation of motion shows a purely diffusive part and the motion of the particles in the potential of mean force resulting from the intermolecular interactions. The theory enables the calculation of the time-dependent surface coverage of proteins, the dynamic surface tension, and the structure of the adsorbed layer in contact with the approaching proteins. For the case of competitive adsorption from a solution containing a mixture of large and small proteins, a variety of different adsorption patterns are observed depending upon the bulk composition, the strength of the interaction between the particles, and the surface and size of the proteins. It is found that the experimentally observed Vroman sequence is predicted in the case that the bulk solution is at a composition with an excess of the small protein, and that the interaction between the large protein and the surface is much larger than that of the smaller protein. The effect of surface conformational changes of the adsorbed proteins in the time-dependent adsorption is studied in detail. The theory predicts regimes of constant density and dynamic surface tension that are long lived but are only intermediates before the final approach to equilibrium. The implications of the findings to the interpretation of experimental observations is discussed.

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Section: Discussionmentioning

confidence: 99%

Kinetics and Thermodynamics of Protein Adsorption: A Generalized Molecular Theoretical Approach

Fang

Szleifer

2001

Biophysical Journal

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154

169

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“…To this end, there has been a plethora of both theoretical/computational and experimental work investigating the organization of copolymers at planar, chemically homogeneous surfaces and homopolymers at planar, chemically heterogeneous surfaces. [8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25] These reports have provided insight into the basic phenomena governing polymer adsorption. It has now been well established that the driving force for polymer adsorption involves an interplay between ͑i͒ the gain in energy due to the adsorption of the binding monomers of the macromolecule to the attractive surface, and ͑ii͒ the loss in chain entropy associated with the reduction in the number of possible configurations of the adsorbed chain relative to that of a free chain in the bulk.…”

Section: Introductionmentioning

confidence: 99%

Monte Carlo simulations of copolymer adsorption at planar chemically patterned surfaces: Effect of surface domain sizes

Semler

Genzer

2003

The Journal of Chemical Physics

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A Monte Carlo simulation of polymer/polymer interface in the presence of block copolymer. I. Effects of the chain length of block copolymer and interaction energy We present results of Monte Carlo simulation studies utilizing the bond fluctuation model in conjunction with single and configurational biased Monte Carlo moves to investigate the adsorption of diblock ͑A-b-B͒ and alternating ͑A-alt-B͒ copolymers at physically flat surfaces made of an equal number of two chemically different sites, C and D. The adsorption of the copolymer to the surface is driven by the repulsion between the A and B segments along the copolymer and the attraction between the B segments and the D sites on the surface. We address the critical role of the commensurability between the copolymer's monomer sequence distribution and the size and spatial distribution of the surface adsorbing sites on the copolymer adsorption. We show that both copolymer architectures have the ability to recognize the surface motif and transcribe it into the bulk material. Diblock copolymers can transfer the pattern once the heterogeneous domain sizes match the size of the parallel component to the radius of gyration, which is constituted primarily of the adsorbing species. This behavior results from the ability of the diblock copolymer to adopt a brush type conformation. In contrast to the diblocks, copolymers with the alternating sequence distribution are more likely to ''zip to'' the surface since the adsorbing species are evenly distributed along the copolymer. This chain conformation creates an entropic penalty, which must be alleviated by the formation of loops and tails. These conformational changes endow the alternating copolymer with the ability to recognize patterns with periodicities much less than the parallel component to the radius of gyration, and to invert the pattern as the distance away from the surface is increased.

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“…The use of this matrix method on lattices such as those shown in Figs lattices, which are difficult, [26][27][28] if not impossible, to treat using continuum methods. As shown previously in the case of striping, i.e., non-uniform surface chemistry, a shift in the phase transition temperature (critical condition) (−ε/k B T) occurs.…”

Section: Resultsmentioning

confidence: 99%

“…To demonstrate the validity and usefulness of combining surface energy structuring and periodic boundary conditions, we chose to examine a structure similar to the one studied by Seok et al, 26 who used an analytical density functional theory of alternating stripes of attractive and repulsive energetics as a function of stripe width. Because of the shift in phase transition observed for the striping case studied earlier in this paper, we first examined the location of the phase transition (critical condition for adsorption −ε c /k B T) as a function of the width of the stripe.…”

Section: Resultsmentioning

confidence: 99%

Exact solution of the thermodynamics and size parameters of a polymer confined to a lattice of finite size: Large chain limit

Snyder

Guttman

Marzio

2014

The Journal of Chemical Physics

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We extend the exact solutions of the Di Marzio-Rubin matrix method for the thermodynamic properties, including chain density, of a linear polymer molecule confined to walk on a lattice of finite size. Our extensions enable (a) the use of higher dimensions (explicit 2D and 3D lattices), (b) lattice boundaries of arbitrary shape, and (c) the flexibility to allow each monomer to have its own energy of attraction for each lattice site. In the case of the large chain limit, we demonstrate how periodic boundary conditions can also be employed to reduce computation time. Advantages to this method include easy definition of chemical and physical structure (or surface roughness) of the lattice and site-specific monomer-specific energetics, and straightforward relatively fast computations. We show the usefulness and ease of implementation of this extension by examining the effect of energy variation along the lattice walls of an infinite rectangular cylinder with the idea of studying the changes in properties caused by chemical inhomogeneities on the surface of the box. Herein, we look particularly at the polymer density profile as a function of temperature in the confined region for very long polymers. One particularly striking result is the shift in the critical condition for adsorption due to surface energy inhomogeneities and the length scale of the inhomogeneities; an observation that could have important implications for polymer chromatography. Our method should have applications to both copolymers and biopolymers of arbitrary molar mass.

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Polymer melts and polymer solutions near patterned surfaces

Cited by 22 publications

References 35 publications

Kinetics and Thermodynamics of Protein Adsorption: A Generalized Molecular Theoretical Approach

Kinetics and Thermodynamics of Protein Adsorption: A Generalized Molecular Theoretical Approach

Monte Carlo simulations of copolymer adsorption at planar chemically patterned surfaces: Effect of surface domain sizes

Exact solution of the thermodynamics and size parameters of a polymer confined to a lattice of finite size: Large chain limit

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