@article{schultz_hall_genzer_2007, title={Obtaining concentration profiles from computer simulation structure factors}, volume={40}, ISSN={["1520-5835"]}, DOI={10.1021/ma062836d}, abstractNote={The structure factor, S(q), is an important analysis tool for analyzing the structure of macromolecular crystals, 1,2 block copolymers, 3 micelles, 4 and the glass transition. 5 As the Fourier transform of the density profile, S(q) gives a quantitative description of the concentration fluctuations in a system as a function of the fluctuation frequency and direction. S(q) can be obtained experimentally from scattering experiments or can be extracted from simulation data on particle positions. In the past,S(q) has been used to determine the size and morphology of micelles, the degree of ordering, the identity of an ordered structure, and even the interaction strength between components of a copolymer. 6-8}, number={8}, journal={MACROMOLECULES}, author={Schultz, Andrew J. and Hall, Carol K. and Genzer, Jan}, year={2007}, month={Apr}, pages={2629–2632} } @article{schultz_hall_genzer_2005, title={Computer simulation of block copolymer/nanoparticle composites}, volume={38}, ISSN={["1520-5835"]}, DOI={10.1021/ma0496910}, abstractNote={Discontinuous molecular dynamics simulation is used to study the phase behavior of diblock copolymer/nanoparticle composites. The copolymers are modeled as chains of tangent hard-spheres with square shoulder repulsions between unlike species, while the nanoparticles are modeled as hard-spheres with a square shoulder repulsion with one of the copolymer blocks. The resulting phase diagrams are presented for composites containing nanoparticles of various sizes and interaction strengths and include lamellae, perforated lamellae, cylinders, and disordered phases. Composites containing large nanoparticles also exhibit two-phase coexistence between different copolymer phases or between a copolymer phase and a nanoparticle phase, depending on the nanoparticle interaction strength. We also present concentration profiles perpendicular to the lamellar interface for nanoparticles of different sizes and interaction strengths. Neutral nanoparticles concentrate at the interface between copolymer domains, while interacti...}, number={7}, journal={MACROMOLECULES}, author={Schultz, AJ and Hall, CK and Genzer, J}, year={2005}, month={Apr}, pages={3007–3016} } @article{schultz_hall_genzer_2004, title={Box length search algorithm for molecular simulation of systems containing periodic structures}, volume={120}, ISSN={["1089-7690"]}, DOI={10.1063/1.1636156}, abstractNote={We have developed a box length search algorithm to efficiently find the appropriate box dimensions for constant-volume molecular simulation of periodic structures. The algorithm works by finding the box lengths that equalize the pressure in each direction while maintaining constant total volume. Maintaining the volume at a fixed value ensures that quantitative comparisons can be made between simulation and experimental, theoretical or other simulation results for systems that are incompressible or nearly incompressible. We test the algorithm on a system of phase-separated block copolymers that has a preferred box length in one dimension. We also describe and test a Monte Carlo algorithm that allows the box lengths to change while maintaining constant volume. We find that the box length search algorithm converges at least two orders of magnitude more quickly than the variable box length Monte Carlo method. Although the box length search algorithm is not ergodic, it successfully finds the box length that minimizes the free energy of the system. We verify this by examining the free energy as determined by the Monte Carlo simulation.}, number={4}, journal={JOURNAL OF CHEMICAL PHYSICS}, author={Schultz, AJ and Hall, CK and Genzer, J}, year={2004}, month={Jan}, pages={2049–2055} } @article{schultz_hall_genzer_2002, title={Computer simulation of copolymer phase behavior}, volume={117}, ISSN={["1089-7690"]}, DOI={10.1063/1.1519839}, abstractNote={Discontinuous molecular dynamics simulation is used to study the phase behavior of diblock copolymers modeled as chains of tangent hard spheres with square shoulder repulsions between unlike species as a function of chain length, volume fraction and interaction strength (χ). The location of the order–disorder transition for a symmetric copolymer is close to the predictions of Fredrickson and Helfand. Our simulation results for packing fractions of 0.35, 0.40, and 0.45 and chain lengths 10 and 20 are summarized in phase diagrams which display disordered, lamellae, perforated lamellae (PL), cylindrical, and BCC spherical (S) phases in the χN versus f plane. These phase diagrams are consistent with phase diagrams from other simulation studies. Contrary to theoretical predictions we observe the PL phase near regions of predicted gyroid stability, and the S phase only in the systems with high packing fraction and long chain length. These discrepancies may be due to the short chain lengths considered, as they are less evident in the 20-bead chains than the 10-bead chains. We examine the structural spacing of the microphases and the variation of that spacing with χN. We also examine the internal energy and entropy and their variation with χN. Our results are consistent with self-consistent field theory results for the strong segregation limit.}, number={22}, journal={JOURNAL OF CHEMICAL PHYSICS}, author={Schultz, AJ and Hall, CK and Genzer, J}, year={2002}, month={Dec}, pages={10329–10338} } @misc{williams_schultz_geiser_carlson_kini_wang_kwok_whangbo_schirber_1991, title={ORGANIC SUPERCONDUCTORS - NEW BENCHMARKS}, volume={252}, ISSN={["1095-9203"]}, DOI={10.1126/science.252.5012.1501}, abstractNote={ Recent advances in the design and synthesis of organic synthetic metals have yielded materials that have the highest superconducting transition temperatures ( T c ≈ 13 kelvin) reported for these systems. These materials have crystal structures consisting of alternating layers of organic donor molecules and inorganic anions. Organic superconductors have various electronic and magnetic properties and crystal structures that are similar to those of the inorganic copper oxide superconductors (which have high T c values); these similarities include highly anisotropic conductivities, critical fields, and short coherence lengths. The largest number of organic superconductors, including those with the highest T c values, are charge-transfer salts derived from the electron donor molecule BEDT-TTF or ET [bis(ethylenedithio)-tetrathiafulvalene]. The synthesis and crystal structures of these salts are discussed; their electrical, magnetic, and band electronic structure properties and their many similarities to the copper oxide superconductors are treated as well. }, number={5012}, journal={SCIENCE}, author={WILLIAMS, JM and SCHULTZ, AJ and GEISER, U and CARLSON, KD and KINI, AM and WANG, HH and KWOK, WK and WHANGBO, MH and SCHIRBER, JE}, year={1991}, month={Jun}, pages={1501–1508} } @misc{williams_wang_emge_geiser_beno_leung_carlson_thorn_schultz_whangbo_1987, title={RATIONAL DESIGN OF SYNTHETIC METAL SUPERCONDUCTORS}, volume={35}, ISSN={["0079-6379"]}, DOI={10.1002/9780470166369.ch2}, abstractNote={This chapter contains sections titled: Introduction Material Syntheses Molecular and Crystal Structures of (ET)nXm Compounds Normal-State and Superconducting Properties of ET-Based Organic Conductors Spectroscopic Studies Band Electronic Structures of ET Salts Bis-Dithiolene Transition Metal Analogues of ET Concluding Remarks Addendum}, journal={PROGRESS IN INORGANIC CHEMISTRY}, author={WILLIAMS, JM and WANG, HH and EMGE, TJ and GEISER, U and BENO, MA and LEUNG, PCW and CARLSON, KD and THORN, RJ and SCHULTZ, AJ and WHANGBO, MH}, year={1987}, pages={51–218} }