Void Microstructuring in Lamellar Phase of Amphiphilic Macromolecules

Глаголева, А. А.; Erukhimovich, I. Ya.; Vasilevskaya, V. V.

doi:10.1002/mats.201200056

Cited by 14 publications

(12 citation statements)

References 19 publications

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“…34 It was shown that such a model allows to describe the unique conformations adopted by macromolecules with amphiphilic monomer units in dilute and concentrated solutions, 34−39 to reconstruct their specific ordering in the bulk 40,41 and near interface. 42−44 In selective solvent, amphiphilic homopolymers sparsely grafted onto a flat substrate can form an ultrathin coating having the width of about two monomer units. 29 Domains oriented perpendicularly to the substrate are observed in densely grafted amphiphilic homopolymers.…”

Section: Introductionmentioning

confidence: 99%

Lamellae—Parking Garage Structure—Lamellae Transition in Densely Grafted Layers of Amphiphilic Homopolymers: Impact of Polymerization Degree

Lazutin

Vasilevskaya

2018

ACS Omega

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By means of computer modeling, the self-organization of densely grafted macromolecules with amphiphilic monomer units as a function of macromolecular polymerization degree and solvent quality was studied and a diagram of state was constructed. The diagram contains fields of disordered distribution of monomer units and of prolonged aggregates, regions of lamellae with small and big domain spacing, and transition region. Within the transition region, the lamellae with different spacing coexist: the lamellae with big domain spacing are on the top of the grafting layer and the lamellae with small domain spacing are close to the grafting surface. The lamellae are connected with each other and form bicontinuous parking garage structure joining all side groups into a single cluster. The domain spacing of lamellae does not depend on the macromolecular length, but the width of the transition region decreases with the decrease of polymerization degree until total vanishing at relatively short macromolecules. The sharp switch between lamellae and bicontinuous structure opens the perspective for practical applications of densely grafted layers with amphiphilic monomer units.

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Section: Introductionmentioning

confidence: 99%

Lamellae—Parking Garage Structure—Lamellae Transition in Densely Grafted Layers of Amphiphilic Homopolymers: Impact of Polymerization Degree

Lazutin

Vasilevskaya

2018

ACS Omega

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“…Molecular simulations such as molecular dynamics and coarse‐grained models have been extensively used to analyze both the static and dynamic properties of polymeric materials. By simplifying detailed chemistry and atomic details, coarse‐grained models provide both computational and conceptual advantages that facilitate numerical calculations and theoretical analyses of complex phenomena .…”

Section: Introductionmentioning

confidence: 99%

Conformational Changes and Dynamics during Adsorption of Macromolecules with Different Degree of Polymerization Studied by Monte Carlo Simulations

Serra

Cabanilles

Dueñas

et al. 2018

Macro Theory & Simulations

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such as polymers, ceramics, or metals is of paramount importance for tissue engineering and regenerative medicine applications. [7][8][9][10] Furthermore, knowledge of the structural formation at the solid/liquid interface is also a key factor in designing micro/nanostructures with promising applications in nanotechnology. [11,12] The phase transition of diluted macromolecules in equilibrium is characterized by conformational changes. [13] Macromolecules diluted in a good solvent favor random coil conformations at high temperatures. When the temperature drops, the macromolecules collapse and adopt a globular conformation with lower conformational entropy than coil structures. However, globular conformation is entropy-dominated and the system evolves toward crystalline conformations. [14][15][16] The presence of an attractive surface could assist adsorbed chains toward crystalline or nematic order, leading to configurations that do not occur on a nonadherent surface. [13,17,18] Reduced motion of a polymer chain is commonly found near the surface during adsorption. The attraction potential between the surface and the monomers is fundamental for the polymer chain to adsorb and remain on the surface. Concentration, temperature, and chain length influence the dynamics of the adsorbed polymer chains. [19] Meta-stable polymer states play an important role in polymer physics. Mainly dependent (though not exclusively) on temperature, the mobility of polymer chains is at times so hindered that meta-stable conformations remain over long periods of time. Both experiments [20] and simulations [21] have revealed the existence of thermodynamically meta-stable states during the coil-to-globule transition. This constraint on mobility produces the glass transition and structural relaxation phenomena. In the glass transition temperature range, the chains become frozen in an out-of-equilibrium state in which conformational motions are severely limited and only local movements are allowed. Below the glass transition temperature the system evolves toward equilibrium in what is known as structural relaxation. [22,23] Molecular simulations such as molecular dynamics [24][25][26][27] and coarse-grained models [28][29][30][31] have been extensively used to analyze both the static and dynamic properties of polymeric materials. By simplifying detailed chemistry and atomic details, Monte Carlo SimulationsDynamics of multilayer adsorption of macromolecules with different degree of polymerization is studied by coarse-grained Monte Carlo simulations, focusing on both the interface macromolecule-surface and chain-chain interaction in and out of equilibrium conditions. The interfacial interaction between the solid flat surface and the macromolecules is modeled by means of a Lennard-Jones potential, and inter-and intrachain interactions are simulated using bond angle, bond length, and Lennard-Jones potentials. The results show that local and conformational motions near the glass transition temperature promote configurations with minimal energy, wh...

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“…The voids are found to concentrate on the interfaces and to perform crystalline-like ordering in case of significant amphiphilicity of units. 40 The theoretical study 41,42 of morphological states of macromolecules with amphiphilic monomer units shows that the crucial factor stabilizing the shape of macromolecules in a condensed globular state is the surface tension decrease due to the polar group orientation towards the external solution.…”

Section: Introductionmentioning

confidence: 99%

New strategy to create ultra-thin surface layer of grafted amphiphilic macromolecules

Lazutin

Govorun

Vasilevskaya

et al. 2015

The Journal of Chemical Physics

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It was found first that macromolecules made of amphiphilic monomer units could form spontaneously an ultra-thin layer on the surface which the macromolecules are grafted to. The width of such layer is about double size of monomer unit consisting of hydrophilic A (repulsive) and hydrophobic (attractive) B beads. The hydrophilic A beads are connected in a polymer chain while hydrophobic B beads are attached to A beads of the backbone as side groups. Three characteristic regimes are distinguished. At low grafting density, the macromolecules form ultra-thin micelles of the shape changing with decrease of distance d between grafting points as following: circular micelles-prolonged micelles-inverse micelles-homogeneous bilayer. Those micelles have approximately constant height and specific top-down A-BB-A structure. At higher grafting density, the micelles start to appear above the single bilayer of amphiphilic macromolecules. The thickness of grafted layer in these cases is different in different regions of grafting surface. Only at rather high density of grafting, the height of macromolecular layer becomes uniform over the whole grafting surface. The study was performed by computer modeling experiments and confirmed in framework of analytical theory.

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Void Microstructuring in Lamellar Phase of Amphiphilic Macromolecules

Cited by 14 publications

References 19 publications

Lamellae—Parking Garage Structure—Lamellae Transition in Densely Grafted Layers of Amphiphilic Homopolymers: Impact of Polymerization Degree

Lamellae—Parking Garage Structure—Lamellae Transition in Densely Grafted Layers of Amphiphilic Homopolymers: Impact of Polymerization Degree

Conformational Changes and Dynamics during Adsorption of Macromolecules with Different Degree of Polymerization Studied by Monte Carlo Simulations

New strategy to create ultra-thin surface layer of grafted amphiphilic macromolecules

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