Publications | Hoowaki

Hydrophobicity of curved microstructured surfaces

This paper presents measurements and models for how the macroscopic curvature of microstructured polymers affects hydrophobicity. Flexible polymer substrates were fabricated with arrays of regular microstructures. The interaction of liquid drops with these surfaces was analyzed for flat substrates and substrates flexed into either positive or negative cylindrical shapes.

Casting metal microstructures from a flexible and reusable mold

This paper describes casting-based microfabrication of metal microstructures and
nanostructures. The metal was cast into flexible silicone molds which were themselves cast
from microfabricated silicon templates.

Visualizing contact line phenomena on microstructured superhydrophobic surfaces

The presence of microstructures or nanostructures on a surface can influence how that surface interacts with liquids. This article reports metrology of microscopic contact line phenomena via metal droplets frozen onto a microstructured surface.

Microstructured metal molds fabricated via investment casting

This paper describes an investment casting process to produce aluminum molds having integrated microstructures. Unlike conventional micromolding tools, the aluminum mold was large and had complex curved surfaces. The aluminum was cast from curved microstructured ceramic molds which were themselves cast from curved microstructured rubber.

Impact of polymer film thickness and cavity size on polymer flow during embossing: toward process design rules for nanoimprint lithography

This paper presents continuum simulations of polymer flow during nanoimprint lithography (NIL). The simulations capture the underlying physics of polymer flow from the nanometer to millimeter length scale and examine geometry and thermophysical process quantities affecting cavity filling.

Nanomaterial transfer using hot embossing for flexible electronic devices

We demonstrate hot embossing to pattern carbon nanotubes (CNTs) on flexible substrates. Patterns of CNTs grown on both microtextured and flat silicon templates were transferred into polymer substrates, with good replication of both the CNT patterns and surface relief features.