(105a) Poly(ethylene oxide) Nanotubes From Electrostatic Layer-by-Layer Assembly

As the size of devices and systems becomes increasingly smaller, the need for high-performance, small-geometry materials increases. Poly(ethylene oxide) (PEO) is a versatile material used in drug delivery, anti-fouling coatings, electrolytes, and more, but PEO has a large crystalline phase and is not water-stable. Here, we discuss the creation and properties of thin films and nanotubes of PEO-urethane ionomers processed using an integrated approach of layer-by-layer assembly and nanotemplating. The resulting structures are stable in water and posses hierarchical structure at the layer-level and template-level.

Layer-by-layer (LbL) assembly is the aqueous-based alternate adsorption of oppositely charged species to a substrate. LbL assembly was performed on an anodic aluminum oxide (AAO) template, where the layers coat the template's pore wall under carefully selected processing conditions. Both films and nanotubes were created, and their growth curves were determined via ellipsometry and reflectometry. Nanotube dimensions and wall-thickness were examined using scanning electron microscopy. A stability test was performed to determine the robustness of the PEO-structures in water of varying ionic strengths. Future work will investigate the swelling behavior of the LbL-nanotubes relative to bulk LbL films.

This work enables the creation of nanoscale energy storage systems such as micro- or nanobatteries and fuel cells, biocompatible drug delivery nanotubes, and water-stable anti-fouling coatings.