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Materials Research Laboratory
Materials Science and Engineering: Polymers
- Mesoporous Polymers
- Anisotropic Polymer Fluids
- Liquids of Branched Macromolecules
- Macromolecule-induced Interactions between Spherical Particles
- Structure of Multiblock Copolymers and Ionomers
^ Mesoporous Polymers
P. V. Braun,* Y. J. Lee
U.S. Department of Energy, DE-FG02-91ER45439
(In cooperation with the Frederick Seitz Materials Research Laboratory)
This work is focused on the synthesis and characterization of polymeric materials which contain a regular distribution of nanometer sized pores. The polymers are synthesized in a lyotropic liquid crystalline media. Under the appropriate conditions, the characteristic dimensionality and structure of the lyotropic liquid crystal is imparted to the polymer during the synthesis. Researchers are exploring routes to both bulk and thin-film materials. The focus is on synthesizing conducting polymers via oxidative processes; however, other polymerization routes may also be applicable.
^ Anisotropic Polymer Fluids
K. S. Schweizer,* G. T. Pickett
U.S. Department of Energy, DE-FG02-91ER45439
(In cooperation with the Frederick Seitz Materials Research Laboratory)
Novel liquid state integral equation theories of fluids composed of polymers with spatially anisotropic conformations are being developed. A new mechanism for nematic and dissotic liquid crystal formation in flexible and semiflexible polymer fluids has been discovered. Generalizations to treat the influence of attractive cohesive forces and rigid rod polymers are under way. Predicting the anisotropic structure of confined polymer thin films is also possible with the new approach.
^ Liquids of Branched Macromolecules
K. S. Schweizer,* T. M. Chang
U.S. Department of Energy, DE-FG02-91ER45439; Oak Ridge National Laboratory
(In cooperation with the Frederick Seitz Materials Research Laboratory)
The structure and thermodynamic properties of many arm star, "core-shell" soft colloids and other highly branched macromolecular fluids are being studied with microscopic statistical mechanical theory. Such systems display unusual equilibrium and dynamic behavior because of the intermediate degree of interpenetration of different macromolecules. Understanding the phase behavior of alloys of such highly branched macromolecules with linear chains is also under study in order to provide molecular-level guidelines for controlling miscibility.
^ Macromolecule-induced Interactions between Spherical Particles
K. S. Schweizer,* Y. L. Chen
U.S. Department of Energy, DE-FG02-91ER45439; Oak Ridge National Laboratory
(In cooperation with the Frederick Seitz Materials Research Laboratory)
Microscopic statistical mechanical theories of the structure and thermodynamics, dilute suspensions of spherical particles in polymer solutions are being developed. The particles may be nanometer-sized proteins or micelles, larger objects such as dendrimers, or micron-sized colloids. The complex influences of particle size, polymer concentration and molecular weight, and steric and specific attractive forces on equilibrium properties are under study. Specific applications to protein–water soluble polymer suspensions and rigid rod polymer solutions are of particular interest.
^ Structure of Multiblock Copolymers and Ionomers
K. S. Schweizer,* K. Kolbet
U.S. Department of Energy, DE-FG02-91ER45439
(In cooperation with the Frederick Seitz Materials Research Laboratory)
Microscopic theories for the conformation and structure of self-assembling multiblock copolymers and ionomers are being developed. The influence of block length and composition on long wavelength concentration fluctuations, microdomain formation, and phase separation temperature have been systematically explored. Application to address small-angle scattering and the microphase behavior of multiblock polyurethane melts and ionomer melts have been carried out. The role of water, nonpolar solvents, and blending with homopolymers on ionomer structure physical clustering and bulk properties are of interest.
