Nanoscale architecture was used to control energy transfer in semiconducting polymers embedded in the channels of oriented, hexagonal nanoporous silica. Polarized femtosecond spectroscopies show that excitations migrate unidirectionally from aggregated, randomly oriented polymer segments outside the pores to isolated, aligned polymer chains within the pores. Energy migration along the conjugate...

We map dilute or semidilute solutions of nonintersecting polymer chains onto a fluid of "soft" particles interacting via a concentration dependent effective pair potential, by inverting the pair distribution function of the centers of mass of the initial polymer chains. A similar inversion is used to derive an effective wall-polymer potential; these potentials are combined to successfully repro...

We have developed and implemented parallel algorithms for the molecular dynamics simulation of synthetic polymer chains. Our package has been specifically designed for distributed–memory machines like the widespread Cray T3E, but it can also be used on clusters of workstations and on a single workstation (i.e., it runs also sequentially). The target molecules are single synthetic polymer chains...

We use a continuum model to investigate the isochoric axial contraction and expansion of a right circular cylindrical specimen composed of a nematic elastomer that is cross-linked in a uniaxial state and then annealed. We build on previous work by relaxing the constraint that the molecular conformation be spherical or uniaxial, allowing instead for biaxiality. The material exhibits an energetic...

We perform lattice Monte Carlo simulation using the bond-fluctuation model to examine the conformation and dynamic properties of a single small flexible ring polymer in the matrix of linear chains as functions of the degree of polymerization of the linear chains. The average conformation properties as gauged by the mean-square radius of gyration and asphericity parameter are insensitive to the ...

Herein we report preparation of polymeric monofunctional nanoparticles (PMNs) through intramolecularly cross-linking the polymer chains sparsely grafted on the surface of sacrificial silica spheres, and a one-to-one coupling reaction between PMNs and linear polymer chains and that between two PMNs.

Thermal transport is critical to the performance and reliability of polymer-based energy devices, ranging from solar cells to thermoelectrics. This work shows that the thermal conductivity of a low band gap conjugated polymer, poly(4,8-bis-alkyloxybenzo[1,2-b:4,5-b']dithiophene-2,6-diyl-alt-(alkylthieno[3,4-b]thiophene-2-carboxylate)-2,6-diyl) (PBDTTT), for photovoltaic applications can be acti...

We consider branching polymers on the planar square lattice with open boundary conditions and exactly calculate correlation functions of k polymer chains that connect two lattice sites with a large distance r apart for odd number of polymer chains k. We find that besides the standard power-law factor the leading term also has a logarithmic multiplier.

We formulate a coarse-grained molecular-dynamics model of polymer chains in solution that includes hydrodynamic interactions, thermal fluctuations, nonlinear elasticity, and topology-preserving solvent mediated excluded volume interactions. The latter involve a combination of potential forces with explicit geometric detection and tracking of chain entanglements. By solving this model with numer...