Standalone Block Copolymer Nanoballoons: Decoupling Self-Assembly from Implementation in Nanomanufacturing

Abstract

We report a facile method to produce isolatable hollow-core elastomeric vesicles, “nanoballoons”, prepared via block copolymer self-assembly in a polymer blend. Poly­(isoprene-block-dimethylsiloxane) (PI–PDMS) diblock copolymers are blended with PDMS homopolymers (h-PDMS) as a “solvent” phase to template the self-assembly of PDMS-tethered vesicles with PI walls. The walls are subsequently crosslinked to yield mechanically stabilized elastomeric vesicles. The h-PDMS inner core and matrix are separated from the vesicles by dialysis to yield the matrix-free nanoballoons. These objects, 0.3–1 μm in diameter, can be further reincorporated into a crosslinkable PDMS. Throughout the self-assembly, recovery, and reincorporation processes we apply several techniques including solvent dispersion/dynamic light scattering (DLS) measurements, transmission electron microscopy (TEM)/energy-dispersive X-ray spectroscopy (EDS), and small-angle X-ray scattering (SAXS) to provide a consilient body of evidence that the nanoballoon morphology is retained. This work presents advanced nanomanufacturing schema that illustrate the decoupling of the thermodynamic and dynamic factors that govern macromolecular self-assembly from the environment in which the self-assembled objects are deployed.

Shelf-Stable Bingham Plastic Polyurethane Thermosets for Additive Manufacturing

“…The EDS mappings show that the fumed silica (Si signal) is well-dispersed throughout the matrix (C signal). Figures n–q show TEM bright-field images of a printed filament, where the silica appears darker. , The networks between fumed silica at the submicrometer scale clearly show in these TEM images; under quiescent conditions, these percolating networks provide the solid-like character that enables the printed objects to resist flow. Both SEM and TEM images show similar morphologies in the uncured and cured states, indicating that these networks are persistent even at high temperature and throughout the curing process.…”

Stimuli-Responsive Macromolecular Self-Assembly

“…As a result, macromolecular self-assembly is more complex than small molecular self-assembly. Moreover, since macromolecules have better processing and mechanical properties than smaller molecules, functional materials formed by macromolecular self-assembly have a wider range of applications [20][21][22].…”