Research

Polymer micelles as drug carriers

Block copolymer micelles are composed of polymer chains with sequences of hydrophilic and hydrophobic blocks. In a dilute aqueous solution, they form spherical or cylindrical nano-objects comprised of several chains with a hydrophobic core and extended hydrophilic corona. Lipophilic drugs can be dissolved in the core of these micelles, while the corona will assure solubility […]

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Diblock copolymer–selective nanoparticle mixtures in the lamellar phase confined between two parallel walls: a mean field model

Lenin S. Shagolsem, Jens-Uwe Sommer
Soft Matter, 8, 11328-11335 (2012)
We present a mean field model for a mixture of AB diblock-copolymers and A-block selective nanoparticles confined between two identical non-selective walls. A horizontally symmetric lamellar structure of the nanocomposite is considered where nanoparticles are allowed to segregate between the polymer–wall interfaces. For a fixed value of […]

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Homo-polymers with balanced hydrophobicity translocate through lipid bilayers and enhance local solvent permeability

Marco Werner, Jens-Uwe Sommer and Vladimir A. Baulin

Soft Matter, 8, 11708-11716 (2012)

Recent experimental studies indicate that polymeric structures with a well-adjusted balance of amphiphilic parts may translocate through self-assembled phospholipid bilayers and enhance the passive trans-membrane transport of smaller molecules. Using a coarse grained lattice Monte Carlo model with explicit solvent we investigate self-assembled lipid […]

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Permeability of lipid bilayers induced by polymers

Lipid bilayers emerge by self-organization of amphiphilic molecules and are the essential component of membranes of living cells. An important task of them is the selective exchange of substances between the cell and its environment. This becomes particularly interesting for delivering foreign molecules and RNA into the cell. In the classical view of cell biology […]

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Critical adsorption controls translocation of polymer chain through lipid bilayers and permeation of solvent

J.-U. Sommer, M. Werner and V. A. Baulin

Europhysics Letters, 98, 18003 (2012)

Monte Carlo simulations using an explicit solvent model indicate a new pathway for translocation of a polymer chain through a lipid bilayer. We consider a polymer chain composed of repeat units with a given hydrophobicity and a coarse-grained model of a lipid bilayer in […]

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Cyclodextrins and their applications

Cyclodextrins can complexate with polymers and thus can be grafted to surfaces. Grafted layers of sliding polymers are constructed from polymers threading through ring-like molecules grafted to a surface. Such grafting mode allows the polymer chains to freely slide inside the ring-like molecules, thus providing additional degree of freedom for grafted polymers.
A cyclic molecule of a cyclodextrin consist […]

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Aggregation of amphiphilic polymers in the presence of adhesive small colloidal particles

V.A. Baulin, A. Johner and J. Bonet Avalos
J. Chem. Phys., 133, 174905 (2010)
The interaction of amphiphilic polymers with small colloids, capable to reversibly stick onto the chains, is studied. Adhesive small colloids in solution are able to dynamically bind two polymer segments. This association leads to topological changes in the polymer network configurations, such as […]

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Micellization of Sliding Polymer Surfactants

V.A. Baulin, N.-K. Lee, A. Johner, C.M. Marques
Macromolecules, 39(2), 871 – 876 (2006)
Following up a recent paper on grafted sliding polymer layers [Macromolecules 2005, 38, 1434−1441], we investigated the influence of the sliding degree of freedom on the self-assembly of sliding polymeric surfactants that can be obtained by complexation of polymers with cyclodextrins. In contrast […]

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Sliding grafted polymer layers

V.A. Baulin, A. Johner, C.M. Marques
Macromolecules, 38(4), 1434 – 1441 (2005)
We study theoretically the structure of sliding grafted polymer layers, or SGP layers. These interfacial structures are built by attaching each polymer to the substrate with a ringlike molecule such as cyclodextrins. Such a topological grafting mode allows the chains to freely slide along the […]

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Self-consistent field theory of brushes of neutral water-soluble polymers

V.A. Baulin, E.B. Zhulina, A. Halperin
J. Chem. Phys., 119, 2874 (2003)
The self-consistent field theory of brushes of neutral water-soluble polymers described by two-state models is formulated in terms of the effective Flory interaction parameter χeff(T,ϕ) that depends on both temperature, T, and the monomer volume fraction, ϕ. The concentration profiles, distribution of free ends and […]

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Signatures of a concentration dependent Flory chi parameter: swelling and collapse of coils and brushes

V. A. Baulin and A. Halperin
Macromolecules, 35, 6432 – 6438 (2002)
The quality of solvents of polymers is often described in terms of the Flory χ parameter typically assumed to depend only on the temperature, T. In certain polymer-solvent systems fitting the experimental data enforces the replacement of (χT) by a concentration-dependent χeff. In turn, this modifies […]

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Concentration dependence of the Flory (X) parameter within two-state models

V. A. Baulin and A. Halperin
Macromolecules, 35, 6432 – 6438 (2002)
The Flory χ parameter is typically assumed to depend only on the temperature, T. Experimental results often require the replacement of this χ(T) by χeff, which depends also on the monomer volume fraction, φ, χeff(φ,T). Such χeff(φ,T) can arise from two-state models, proposed for polyetheleneoxide (PEO) and […]

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