A proposed simple, portable, robust apparatus, capable of automated operation, has been proposed for collecting samples of selected biological or chemical species in harsh environments. The sampled species could range in size from molecules to nanoparticles (that is, particles with dimensions of the order of nanometers). The apparatus would select a biological or chemical species of interest for sampling by utilizing a combination of (1) electrostatic or electrodynamic fields and (2) a sieve containing holes of predetermined size.

Particles Would Be Ionized, filtered through nanopores, and decelerated by an electric field in the capture vessel.
The apparatus (see figure) would include an ionizing grid, the sieve, an electric- ally insulating capture vessel, and a back electrode at the far end (the right end in the figure) of the capture vessel. The sieve would consist of a porous disk of silicon carbide on silicon, supported by an electrically insulating ceramic ring that would be sealed to the left end of the capture vessel. The sieve would contain an array of nanopores formed by a photoelectrochemical etching process. The nanopores would be made to taper toward narrower openings on the capture-vessel side. A metallic film could be deposited on a surface of the SiC sieve for electrical contact.

In operation, entering particles would be ionized by use of static or pulse discharges in the ionizing grid. An electric potential would be applied to the sieve, causing the ionized particles to accelerate toward and through the sieve. The opposite potential would be applied to the back electrode. Particles would be selected for passage according to their sizes and the sizes of pores in the sieve. After passing through the sieve, the particles would be decelerated by the electric field between the sieve and the back electrode. Condensable molecules would be collected on the inner surface of the capture vessel. Data sampling can be accomplished remotely by spectrographically imaging a thin-film silicon carbide port incorporated into the middle of the backplane.

This work was done by Margaret Ryan, Virgil Shields, and Roger Williams of Caltech for NASA’s Jet Propulsion Laboratory.

In accordance with Public Law 96-517, the contractor has elected to retain title to this invention. Inquiries concerning rights for its commercial use should be addressed to

Intellectual Property group
JPL
Mail Stop 202-233
4800 Oak Grove Drive
Pasadena, CA 91109
(818) 354-2240

Refer to NPO-30182, volume and number of this NASA Tech Briefs issue, and the page number.

Topics:
Biological sciences Ceramics Chemicals Emissions Exhaust emissions Imaging and visualization Insulation Marine vehicles and equipment Optics Particulate matter (PM) Physical Sciences Vehicles
This Brief includes a Technical Support Package (TSP).
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Electrostatic/Electrodynamic Nanoparticle-Capture Vessel

(reference NPO-30182) is currently available for download from the TSP library.

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NASA Tech Briefs Magazine

This article first appeared in the November, 2002 issue of NASA Tech Briefs Magazine (Vol. 26 No. 11).

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Overview

The document outlines a technical support package for an innovative Electrostatic/Electrodynamic Nanoparticle-Capture Vessel developed by researchers at NASA's Jet Propulsion Laboratory (JPL). The invention, credited to Margaret Ryan, Virgil Shields, and Roger Williams, is designed for the automated collection of biological and chemical samples in harsh environments, making it particularly suitable for planetary missions and other challenging atmospheric conditions.

The apparatus operates by ionizing incoming particles using static or pulse discharges within an ionizing grid. Once ionized, these particles are accelerated toward a porous sieve made of silicon carbide (SiC) that contains tapered nanopores. The design of the sieve allows for the selective passage of particles based on their size, as the nanopores are narrower on the side facing the capture vessel, minimizing the loss of samples during the collection process. After passing through the sieve, the particles are decelerated by an electric field created between the sieve and a back electrode, allowing condensable molecules to be collected on the inner surface of the capture vessel.

The document emphasizes the key characteristics of the porous layer, which is formed through a photoelectrochemical etching process. This process creates tapered nano-pores that enhance the efficiency of sample collection. Additionally, a thin metallic film can be applied to the surface of the SiC layer to improve its electrical properties.

The proposed system is noted for its simplicity, portability, and robustness, enabling it to operate automatically and remotely. This capability is crucial for missions that require environmental sampling without direct human intervention. The concentration of captured species is expected to increase over time, depending on the relative concentration in the sampled volume.

The document also includes a notice regarding the retention of rights for commercial use of the invention, directing inquiries to the JPL Intellectual Property group. Overall, this nanoparticle-capture vessel represents a significant advancement in the field of environmental sampling, offering a lightweight and low-power solution for detecting and analyzing chemical and biological species in various atmospheric conditions.