Tethered chains in poor solvent conditions: An experimental study involving Langmuir diblock copolymer monolayers

Kent, Michael S.; Majewski, Jarosław; Smith, Gregory S.; Lee, L. T.; Satija, Sushil K.

doi:10.1063/1.478223

Cited by 15 publications

(18 citation statements)

References 55 publications

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“…To validate the PDMS polymer model, we first perform equilibrium simulations only with the MD solver. According to some widely accepted results, the equilibrium properties of polymer brushes are determined by the excluded-volume interaction and conformation entropy of the polymer chains, and the polymer heights follows the scaling law as [48][49][50] :…”

Section: Polymer Brushesmentioning

confidence: 99%

Concurrent coupling of atomistic simulation and mesoscopic hydrodynamics for flows over soft multi-functional surfaces

Wang

et al. 2019

Soft Matter

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We develop an efficient parallel multiscale method that bridges the atomistic and mesoscale regimes, from nanometer to micron and beyond, via concurrent coupling of atomistic simulation and mesoscopic dynamics. In particular, we combine an all-atom molecular dynamics (MD) description for specific atomistic details in the vicinity of the functional surface, with a dissipative particle dynamics (DPD) approach that captures mesoscopic hydrodynamics in the domain away from the functional surface. In order to achieve a seamless transition in dynamic properties we endow the MD simulation with a DPD thermostat, which is validated against experimental results by modeling water at different temperatures. We then validate the MD-DPD coupling method for transient Couette and Poiseuille flows, demonstrating that the concurrent MD-DPD coupling can resolve accurately the continuum-based analytical solutions. Subsequently, we simulate shear flows over polydimethylsiloxane (PDMS)-grafted surfaces (polymer brushes) for various grafting densities, and investigate the slip flow as a function of the shear stress. We verify that a "universal" power law exists for the sliplength, in agreement with published results. Having validated the MD-DPD coupling method, we simulate time-dependent flows past an endothelial glycocalyx layer (EGL) in a microchannel. Coupled simulation results elucidate the dynamics of EGL changing from an equilibrium state to a compressed state under shear by aligning the molecular structures along the shear direction. MD-DPD simulation results agree well with results of a single MD simulation, but with the former more than two orders of magnitude faster than the latter for system sizes above one micron. * The first two authors contribute equally to this work.

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Section: Polymer Brushesmentioning

confidence: 99%

Concurrent coupling of atomistic simulation and mesoscopic hydrodynamics for flows over soft multi-functional surfaces

Wang

et al. 2019

Soft Matter

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“…There are extensive experimental − and theoretical works as well as simulation studies − on grafted AB diblock copolymer brushes in a selective solvent that is poor for one block but good for the other block. However, experimental investigations , and theoretical and simulation studies of the behavior of grafted block copolymers immersed in a solvent that is poor for both blocks are less developed. Zhulina et al used a two-dimensional self-consistent field calculations and scaling arguments to determine the behavior of grafted AB diblock copolymers, where the surrounding solution is assumed to be a poor solvent for both components.…”

Section: Introductionmentioning

confidence: 99%

Self-Assembled Morphologies of Diblock Copolymer Brushes in Poor Solvents

Jiang

Wang

et al. 2012

Macromolecules

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Self-assembled morphologies of grafted linear AB diblock copolymers are investigated by a simulated annealing method. The copolymers are tethered to a flat substrate by the ends of the A blocks and immersed in a solution that is poor for both A and B components but exhibits a slight preference for one of the blocks. The morphological dependence of the system on the solvent selectivity, polymer grafting density, and the block lengths is investigated systematically. Phase diagrams for systems with two different grafting densities are constructed for the case where the chains are tethered by the less insoluble blocks. At a moderate grafting density, a variety of complicated morphologies, such as spherical pinned micelles, wormlike micelles, and stripe structures, are observed by varying the block lengths. Other complicated morphologies, such as perforated layers and complete layers, can be formed at a relatively high grafting density. More interestingly, by adjusting the length of copolymer chains and the volume fraction of the more insoluble block, some novel morphologies can be induced, ranging from “spheres-in-stripe” and “rods- in-stripe” structures at the moderate grafting density to “spheres-in-layer” and “rods-in-layer” structures at the higher grafting density. It is also observed that garlic-like and caterpillar-like structures can be obtained only when the solvent is more selective for the top block, consistent with previous theoretical results. Furthermore, the effect of the incompatibility of the two blocks on the structural evolution is also investigated.

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“…Polymer brushes have been extensively studied using theoretical approaches (4-7), scaling concepts (7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17), computer models (15,16,(18)(19)(20)(21)(22)(23)(24)(25)(26)(27)(28)(29), and experiments (30)(31)(32)(33)(34)(35)(36)(37). However, most of those studies examined essentially infinite brushes (e.g., simulations use periodic boundary conditions, experiments use macroscopically large brushes, etc.…”

Section: Introductionmentioning

confidence: 99%

Solid Phase DNA Amplification: A Brownian Dynamics Study of Crowding Effects

Mercier

Slater

2005

Biophysical Journal

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Solid phase amplification (SPA), a new method to amplify DNA, is characterized by the use of surface-bound primers. This limits the amplification to two-dimensional surfaces and therefore allows the easy parallelization of DNA amplification in a single system. SPA leads to the formation of small but dense DNA brushes, called DNA colonies. For a molecule to successfully duplicate itself, it needs to bend so that its free end can find a matching primer, located on the surface. We used Brownian dynamics simulations (with a united-atom model) to model the basic kinetics of an SPA experiment. The simulations mimic the temperature cycles and the molecule duplication process found in SPA. Our results indicate that the steric interaction between molecules leads to a decreased duplication probability for molecules in the center of a colony and to an outward leaning for the molecules on the perimeter. These effects result in slower amplification (compared to solution PCR) and indicate that steric interaction alone can explain the loss of the exponential growth (characteristic of solution PCR) of the number of molecules in an SPA experiment. Furthermore, the growth of the colony as a function of the number of thermal cycles is found to be similar to the one obtained with a simple Monte Carlo simulation.

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Tethered chains in poor solvent conditions: An experimental study involving Langmuir diblock copolymer monolayers

Cited by 15 publications

References 55 publications

Concurrent coupling of atomistic simulation and mesoscopic hydrodynamics for flows over soft multi-functional surfaces

Concurrent coupling of atomistic simulation and mesoscopic hydrodynamics for flows over soft multi-functional surfaces

Self-Assembled Morphologies of Diblock Copolymer Brushes in Poor Solvents

Solid Phase DNA Amplification: A Brownian Dynamics Study of Crowding Effects

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