Rearrangement of the Conformational Structure of Polyampholytes on the Surface of a Metal Nanowire in a Transverse Microwave Electric Field

Abstract

Molecular dynamics has been employed to study the rearrangement of the conformational structure of polyampholytes adsorbed on the surface of a gold nanowire with a periodic change in time of its polarity in the transverse direction at an ultrahigh frequency. The radial distributions of the atomic density of the polypeptide and its angular distributions on the nanowire surface have been calculated. At high temperatures, temporary fluctuations in the conformational structure of the adsorbed polyampholyte polypeptide were observed. In this case, for half the period of the nanowire polarity change, the macrochain conformation changed from dense enveloping of the nanowire to an elongated conformational structure along the dipole moment of the nanowire. At low temperature and the nanowire dipole moment, the swelling of the fringe of the adsorbed polyampholyte was observed with a displacement of most of its links to one side with respect to the plane perpendicular to the direction of the nanowire dipole moment and passing through its axis. At low temperature and high values of the nanowire dipole moment, the polyampholyte polypeptide was desorbed from the nanowire surface. An analytical model of conformational rearrangements of a polyampholyte Gaussian chain in the form of an external field perturbation theory is presented.

Modeling of Conformational Changes of Polyelectrolytes on the Surface of a Transversely Polarized Metal Nanowire in an External Electric Field

“…We can also note further prospects for such studies of conformational changes in adsorbed polyelectrolytes on the surfaces of gold nanoparticles. Of great interest, in addition to spherical [15][16][17] and cylindrical [18][19][20] nanoobjects, is the study of conformational rearrangements on the surface of spheroidal gold nanoparticles with different anisotropy in order to obtain nanosystems with tunable plasmon characteristics. On the surface of a prolate [21][22][23] or oblate spheroidal nanoparticle, both charged and polarized along the rotation axis, the distribution of electric charges differs significantly from the cases of charge distribution on the surface of polarized spherical or cylindrical nanoobjects.…”

“…It was shown in [19] that the functions (11) with m=0 and m=1 are especially important for constructing the first-order perturbation theory. In this case, the density…”

“…are taken into account, are equal to zero for states (8) or (11) [19]. However, the correct use of the Rayleigh-Schrodinger perturbation theory requires taking into account states (11) with m=1 to clarify the basic states 00 ( ), ( )…”

“…Previously, the authors studied electrically induced conformational changes in macromolecular chains on the surface of gold nanoobjects of spherical [15][16][17] and cylindrical [18][19][20] shapes, as well as on the surface of gold prolate nanospheroids [21][22][23] and the flat surface of a gold crystal. It was shown that under the influence of both a static external electric field and microwave electromagnetic radiation, the conformational structure of polyelectrolyte chains adsorbed on the surface of metal nanoobjects changes significantly, and at the same time depends on the shape of the nanoobject.…”

“…It was shown that under the influence of both a static external electric field and microwave electromagnetic radiation, the conformational structure of polyelectrolyte chains adsorbed on the surface of metal nanoobjects changes significantly, and at the same time depends on the shape of the nanoobject. At the same time, it is of interest to study conformational changes in polyelectrolytes with a uniform distribution of charges of the same sign along the entire macrochain on the surface of a metal cylindrical nanowire or nanorod polarized in the transverse direction in a static electric field, which was not disclosed in previously published works [18][19][20].…”