Asymmetric Charge Patterning on Surfaces and Interfaces
Sharon Loverde, Department of Chemical and Biomolecular Engineering, University of Pennsylvania, Philadelphia, PA 19103 and Monica Olvera de la Cruz, Northwestern University, Evanston, IL 60208.
Pattern formation at interfaces is governed by a characteristic 'nano' length-scale, determined by the associated relevant competing interactions. It has been shown that lamellar and hexagonal patterns can form on interfaces, for a wide variety of systems--semiconductors, metal alloys, membranes, block copolymer melts, and reactive blends. In this study, the asphericity of charged domains is considered for different strengths of the electrostatics, determined by the interface media, relative to the short range van der Waals interactions between the molecular components. The phase behavior of the surface structure is explored, using molecular dynamics simulations. Additionally, dynamic aspects of the interaction between neighboring domains are characterized using the Lindemann criterion. It is found that the charge ratio of the electrostatic components strongly influences the shape of the domains, as well as the degree of local order in the inter-domain structure.