Diblock copolymers blended with homopolymer may self-assemble into spherical, cylindrical, or lamellar aggregates. Transitions between these structures may be driven by varying the homopolymer diblock molecular weight or composition. Using self-consistent field theory (SCFT), we reproduce these effects. Our results are compared to x-ray scattering and transmission electron microscopy measuremen...

The Γ-limit of the Ohta-Kawasaki density functional theory of diblock copolymers is a nonlocal free boundary problem. For some values of block composition and the nonlocal interaction, an equilibrium pattern of many spheres exists in a three dimensional domain. A sub-range of the parameters is found where the multiple sphere pattern is stable. This stable pattern models the spherical phase in t...

This work investigates polymeric coating of evaporated induced self-assembly (EISA) mesoprous silica nanoparticles for potential use in controlled drug release and therapeutics. As demonstrated here, lipid bilayer coatings can be easily replaced with different polymer analogs allowing for dynamic response to environmental stimuli. In addition to coupling commercially available diblock polymers ...

Encapsulation of dsDNA fragments (contour length 54 nm) by the cationic diblock copolymer poly(butadiene-b-N-methyl-4-vinyl pyridinium) [PBd-b-P4VPQ] has been studied with phase contrast, polarized light, and fluorescence microscopies, as well as scanning electron microscopy. Encapsulation was achieved with a single emulsion technique. For this purpose, an aqueous DNA solution is emulsified in ...

The MIT Faculty has made this article openly available. Please share how this access benefits you. Your story matters. Abstract The self-assembly of gyroid-forming diblock copolymers confined in cylindrical geometry is studied using a combination of computer simulations and experiments. The simulations, based on a system qualitatively representative of poly(styrene-b-isoprene), are performed wi...

Project Objectives. The molecular self-assembly of diblock copolymers provides a simple, robust route to create well-defined arrays of functional nanostructures. In recent work, funded by the NSF Partnership in Nanotechnology: Functional Nanostructures program, we developed techniques by which diblock copolymer thin-films can be transformed into robust nanoporous array templates, and then with ...

Micellar solutions of polystyrene-block-polybutadiene and polystyrene-block-polyisoprene in propane are found to exhibit significantly lower cloud pressures than the corresponding hypothetical nonmicellar solutions. Such a cloud-pressure reduction indicates the extent to which micelle formation enhances the apparent diblock solubility in near-critical and hence compressible propane. Concentrati...

Thermal composition fluctuations and the associated crossover from the 3D Ising to the isotropic Lifshitz universality class have been studied in a three component mixture made of a critical polymer blend and the corresponding diblock copolymer. The critical exponents were found to be appreciably larger than those of the 3D Ising, in agreement with expectations from the larger upper critical di...

We have studied thermal composition fluctuations of a ternary symmetric homopolymer/diblock copolymer system of PEE/PDMS/PEE-PDMS @PEE and PDMS being poly~ethyl ethylene! and poly~dimethyl siloxane!, respectively# in its disordered state with small angle neutron scattering for concentration F of diblocks up to 15%. The phase diagram shows three characteristic regimes; ~1! below the Lifshitz con...