title: Interaction between brush layers of bottle-brush polyelectrolytes: molecular dynamics simulations.
abstract: Interactions between tethered layers composed of aggrecan (charged bottle-brush) macromolecules are responsible for the molecular origin of cartilage biomechanical behavior. To elucidate the role of the electrostatic forces in interaction between bottle-brush layers, we have performed molecular dynamics simulations of charged and neutral bottle-brush macromolecules tethered to substrates. In the case of charged bottle-brush layers, the disjoining pressure P between two brush layers in salt-free solutions increases with decreasing distance D between substrates as P ∝ D(-1.8). A stronger dependence of the disjoining pressure P on the surface separation D was observed for neutral bottle-brushes, P ∝ D(-4.6), in the same interval of disjoining pressures. These scaling laws for dependence of disjoining pressure P on distance D are due to bending energy of the bottle-brush macromolecules within compressed brush layers. The weaker distance dependence observed in polyelectrolyte bottle-brushes is due to interaction between counterion clouds surrounding the bottle-brush macromolecules preventing strong brush overlap.
authors.affiliation: Polymer Program, Institute of Materials Science and Department of Physics, University of Connecticut, Storrs, Connecticut 06269, USA.
authors.forename: Daniel
authors.initials: D
authors.lastname: Russano
authors.forename: Jan-Michael Y
authors.initials: JM
authors.lastname: Carrillo
authors.forename: Andrey V
authors.initials: AV
authors.lastname: Dobrynin
mesh_terms: D004573:Electrolytes / Q000737:chemistry; D056004:Molecular Dynamics Simulation; D010316:Particle Size; D011108:Polymers / Q000737:chemistry*; D013499:Surface Properties
chemical_list: D004573:Electrolytes; D011108:Polymers