SBIR-STTR Award

This Small Business Innovation Research Phase I project strives to control the chemical properties and the morphological structure of a polymer nano-composite surface, at scales ranging from nanometers to the macroscopic, to achieve superhydrophobic and icephobic properties while exhibiting scratch and abrasion resistance. The goal is to apply this knowledge to manufacture superhydrophobic and icephobic surfaces over large areas and at low cost for commercial and defense applications. Materials design of nano-micro-macro scale surface features will be guided by experimental and model-based analysis to optimize the wetting and mechanical durability of the surfaces. This project's contributions to polymer science would include a fundamental understanding of the relationship between polymer structure, molecular weight and viscosity on the formation of nanocomposite materials with a specific structure, as well as optimization of a processing route to achieve a desired surface morphology. Contributions to surface science would include an understanding of the impact of surface morphology over several different length scales on the wetting behavior of liquid water as well as super-cooled water droplets. The broader impact/commercial potential of this project would be improvements in the safety of food handling equipment, as well as the performance and reliability of outdoor infrastructure that is subject to icing conditions, such as stadium roofs, wind turbines, aircraft, and naval structures. Equipment used to wash food can harbor bacterial in areas that retain water. By applying a scratch- and abrasion-resistant superhydrophobic surface, safety would be significantly improved, as the potential for water to be harbored in reservoirs would be greatly reduced. Surfaces that repel super-cooled water could be used outdoors to prevent the formation and accretion of ice layers. In this way the safety of numerous structures could be improved, as the added weight of ice accumulation would be avoided. For example, these surfaces could be used to prevent the accumulation of ice on aircraft surfaces. Avoiding the build-up of relatively small amounts of ice can provide a significant margin of safety, because the impact of icing on airflow patterns, rather than the added weight, is the cause of icing-related aircraft accidents. The mechanical durability of the surface would insure that the superhydrophobic properties are retained for many years even when exposed to rough handling conditions

This Small Business Innovation Research (SBIR) Phase II project will leverage the advances we
made in fabricating flexible polymer surfaces that shed water at low tilt angles while remaining
superhydrophobic after abrasion. In Phase I we developed a model which correlated surface
morphology with mechanical robustness. In Phase II we will apply this model to the
development of a processes compatible with high speed, large-scale fabrication techniques.
The roofing industry seeks material that is self-cleaning, anti-fouling and is highly resistant to
weather events over time. A durable, superhydrophobic polymeric roof membrane will meet
this market need. Commercial success depends on (1) qualifying production speeds up to 100
feet/min, (2) proving compliance to current product requirements and (3) showing value-add.
Phase II studies will elucidate the mechanisms that contribute to the stability of the surfaces
when exposed to UV light, allowing us to improve weatherability. Having demonstrated the
self-cleaning properties of our polymer surfaces in Phase I, we will focus on anti-fouling
properties in Phase II (i.e. low bacterial adhesion and reduced algae growth.)


The broader impact of this SBIR Phase II project will be twofold. Foremost, a direct impact will
be revenue and job growth in the US manufacturing sector. Secondarily, the technology will
support federal policy goals on energy and the environment. Approximately $40 billion is spent
annually in the US to air condition buildings. DOE funded studies show that in warm climates,
substituting a cool roof for a conventional roof can reduce carbon emissions which drive
climate change. Cool roofs also relieve strain on the electrical grid by reducing peak power
demand. Widespread use of cool roofs can improve air quality, hence human health, by
slowing the formation of smog. Superhydrophobic polymer membranes fabricated using
technology developed in this proposal will help keep roofs clean and better able to reflect heat.
Furthermore, coating of outdoor infrastructure equipment, such as wind turbine blades and offshore
energy exploration platforms, will enable the safe operation of such facilities during icing
conditions due to the ability of the superhydrophobic surface to prevent ice accretion. Field
tests are underway. Food handling equipment will benefit from reduced adhesion of bacteria
to surfaces, thus improving food safety.