Session: Research Posters

Paper Number: 120145

120145 - Investigation of Particle Aggregation Behavior in Anti-Dust Nanostructures 

Passive dust mitigation is one of the grand challenges for the explorations of the lunar and other extraterrestrial environments. The Apollo missions discovered this challenge when seals were clogged, spacesuits were damaged, and mechanical components on the craft were quickly degraded. The key challenge for creating passive dust mitigation is minimizing the adhesion forces, depends on surface chemistry and contact area. In prior work, we demonstrated that surface nanostructures can minimize the adhesion force of particulates and result in dust-mitigation properties. Our results demonstrated that structures with a 500 nm period can reduce coverage area of lunar dust by 93.1%. However, questions regarding the particle aggregation and adhesion behavior remain, which is crucial in designing a dust-mitigation surface that is broadly applicable.

In this work, we investigate the particle aggregation behavior and removal mechanisms in anti-dust nanostructured surfaces by controlling the particle density. The proposed nanostructures are fabricated on polycarbonate substrates using a highly scalable nanocoining and thermal nanoimprint process.  These structures have been fabricated with a wide array of feature sizes and periods ranging from 3 to 0.4 µm to vary the surface area.  To examine the particle aggregation behavior, we use two methods to apply the lunar dust. The first is to apply the dust via a spoon, which results in a thick layer of dust. The second is to apply the dust via a pressure controlled spray, where a thin layer of dust can be applied. The residual particles can then be analyzed using confocal and scanning electron microscopy (SEM) to quantify the particle mitigation properties.

Initial tests have been performed, and applying lunar dust simulant to the surface of a 500 nm periodic sample via spoon coating shows effective dust-mitigation properties when tilted vertically However, when applying the dust by spraying, the same sample collects significantly more dust. Furthermore, spoon coating more dust onto a dust sprayed sample has shown to remove dust on the surface, resulting in the <10% dust coverage that was previously obtained.  These results show that the mechanisms behind dust removal depends highly on particle density. We will present the detailed fabrication methods and the mechanisms behind dust adhesion by observing changes in aggregation and surface contact of dust particles on the surface when sprayed or spoon coated. An understanding of the cause of this coating method dependence on the effectiveness of the dust mitigating nanostructures will allow for refined manufacturing techniques to broaden the potential applications of such a surface.  This insight will enable these highly scalable nanostructures to be implemented in applications such as space exploitation, solar panels, and anti-dust windshields.   

Presenting Author: Andrew Tunell University of Texas at Austin

Presenting Author Biography: Graduate Researcher in Dr. Chih-Hao Chang's Nanostructures and Nanomanufacturing Laboratory at the University of Texas at Austin, with a research emphasis on particle interactions with periodic nanostructures.

Authors:

Andrew Tunell University of Texas at Austin
Chih-Hao Chang University of Texas at Austin
Stephen Furst Smart Material Solutions Inc.
Nichole Cates Smart Material Solutions Inc
Lauren Micklow Smart Material Solutions Inc.