9 research outputs found
Partially Annealed Disorder and Collapse of Like-Charged Macroions
Charged systems with partially annealed charge disorder are investigated
using field-theoretic and replica methods. Charge disorder is assumed to be
confined to macroion surfaces surrounded by a cloud of mobile neutralizing
counterions in an aqueous solvent. A general formalism is developed by assuming
that the disorder is partially annealed (with purely annealed and purely
quenched disorder included as special cases), i.e., we assume in general that
the disorder undergoes a slow dynamics relative to fast-relaxing counterions
making it possible thus to study the stationary-state properties of the system
using methods similar to those available in equilibrium statistical mechanics.
By focusing on the specific case of two planar surfaces of equal mean surface
charge and disorder variance, it is shown that partial annealing of the
quenched disorder leads to renormalization of the mean surface charge density
and thus a reduction of the inter-plate repulsion on the mean-field or
weak-coupling level. In the strong-coupling limit, charge disorder induces a
long-range attraction resulting in a continuous disorder-driven collapse
transition for the two surfaces as the disorder variance exceeds a threshold
value. Disorder annealing further enhances the attraction and, in the limit of
low screening, leads to a global attractive instability in the system.Comment: 21 pages, 2 figure
Statistical mechanics of DNA adsorption on a carbon nanotube
The attraction between the polycyclic aromatic surface elements of carbon nanotubes (CNT) and the aro-
matic nucleotides of deoxyribonucleic acid (DNA) leads to reversible adsorption (physisorption) between
them. With the goal to provide the theoretical support to numerous technologies on the basis of DNA-CNT
hybrids, we propose a Hamiltonian formulation for the zipper model that accounts for relevant interactions
and allows for the processing of experimental data, which has awaited an available theory for a decade
Statistical mechanics of DNA-nanotube adsorption
Attraction between the polycyclic aromatic surface elements of carbon nanotubes (CNT) and the
aromatic nucleotides of deoxyribonucleic acid (DNA) leads to reversible adsorption (physisorption)
between the two, a phenomenon related to hybridization. We propose a Hamiltonian formulation
for the zipper model that accounts for the DNA-CNT interactions and allows for the processing of
experimental data, which has awaited an available theory for a decade