title: Computing free energies of interfaces in self-assembling systems.
abstract: Using molecular simulation of a coarse-grained model for a symmetric diblock copolymer melt, we calculate the free energy of interfaces between lamellar morphologies with different orientations. Two examples are considered: (a) a T-junction between two lamellar structures with perpendicular orientation and (b) a surface reconstruction that arises when lamella-forming diblock copolymers assemble on a stripe-patterned surface, where the pattern period is significantly larger than the lamellar spacing in the bulk. The computational scheme relies on reversibly relating the defect structure to a reference state by an external ordering field. Free energy differences are accurately obtained by using a combination of expanded-ensemble and replica-exchange Monte Carlo techniques.
authors.affiliation: Institut für Theoretische Physik, Georg-August-Universität, 37077, Göttingen, Germany. mmueller@theorie.physik.uni-goettingen.de
authors.forename: Marcus
authors.initials: M
authors.lastname: Müller
authors.forename: Kostas Ch
authors.initials: KCh
authors.lastname: Daoulas
authors.forename: Yuki
authors.initials: Y
authors.lastname: Norizoe