Nanopatterns in tethered membranes of weakly charged chains with hydrophobic backbones

Weakly charged tethered membranes or thin gels adsorbed on surfaces with hydrophobic backbone can undergo transitions from a swollen state to a nanophase segregated state as the strength of the backbone attraction increases. The strength of electrostatic interactions can be tuned by the salt concentration. As the salt concentration increase, the electrostatic interactions become weaker. The gel collapses at a critical salt concentration, and almost all nanoparticles are expelled to the surrounding medium. Furthermore, as the concentration of salt increases, the nanophase segregated system undergoes a transition to a macrophase segregated state. All these transitions are accompanied by large changes in the dimensions of the system, a characteristic of charged gels. It is observed that the local ionic density fluctuations are large in the nanophase segregated state.