Alexander N. Semenov

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A generic statistical mechanical model is presented for the self-assembly of chiral rod-like units, such as beta-sheet-forming peptides, into helical tapes, which with increasing concentration associate into twisted ribbons (double tapes), fibrils (twisted stacks of ribbons), and fibers (entwined fibrils). The finite fibril width and helicity is shown to(More)
Two models of dense two-dimensional (2d) polymers are considered: (1) when chain intersections in 2d are totally forbidden, and (2) when they are allowed to some extent. It is shown that both polymer chain statistics and dynamics are entirely different for the two models. In the first case studied by Duplantier in 1986 polymer chains are essentially(More)
  • A N Semenov
  • The European physical journal. E, Soft matter
  • 2002
Adsorption of ideal polymers with stiff backbone onto a flat surface is considered theoretically. Both scaling approach and quantitative theory are developed. We predict a self-similar monomer concentration profile c(x) approximately x(-4/3) near the surface (when the distance to the surface x is much smaller than the chain persistence length l /2). The(More)
Ionic equilibria in "water-water-immiscible organic solvent" systems have been studied. It has been shown that in such systems shift of the apparent pK value of acids and bases takes place (compared to aqueous solutions), the value of the shift being rather high, up to 5 and more pH units (with 2,4-dinitrophenyltryptophan as an acid and neutral red as a(More)
The scaling of the bond-bond correlation function P1(s) along linear polymer chains is investigated with respect to the curvilinear distance s along the flexible chain and the monomer density rho via Monte Carlo and molecular dynamics simulations. Surprisingly, the correlations in dense three-dimensional solutions are found to decay with a power law P1(s)(More)
We address the problem of classification of the type of association (multimerization) in solutions of identical unimers. Although the aggregation is still routinely characterized in terms of either "open association" or "closed association" models, neither of the two models can provide a fair description of many aggregation processes. We demonstrate that a(More)
By using a combination of experimental and theoretical tools, we elucidate unique physical characteristics of supramolecular triarylamine nanowires (STANWs), their packed structure, as well as the entire kinetics of the associated radical-controlled supramolecular polymerization process. AFM, small-angle X-ray scattering, and all-atomic computer modeling(More)
The influence of applied electric field, temperature variation rate, and free charge carrier density on the hysteresis of C T dependence is investigated on ferroelectric ceramic capacitors. The measurements were performed on the ceramic capacitors of Ba0.55Sr0.45TiO3 containing 12 wt % of Mg complex additive and the 0.87Pb Mg1/3Nb2/3 O3–0.13PbTiO3 ceramics.(More)
Surface structures of semifluorinated alkanes F(CF(2))(n)(CH(2))(m)H (referred to as FnHm) spread on the air/water interface are investigated theoretically. The study is focused on the disklike surface micelles that were recently identified by AFM and scattering techniques at sufficiently high surface concentrations. We show that (1) the micelles emerge as(More)