title: Particle Fabrication Using Inkjet Printing onto Hydrophobic Surfaces for Optimization and Calibration of Trace Contraband Detection Sensors.
abstract: A method has been developed to fabricate patterned arrays of micrometer-sized monodisperse solid particles of ammonium nitrate on hydrophobic silicon surfaces using inkjet printing. The method relies on dispensing one or more microdrops of a concentrated aqueous ammonium nitrate solution from a drop-on-demand (DOD) inkjet printer at specific locations on a silicon substrate rendered hydrophobic by a perfluorodecytrichlorosilane monolayer coating. The deposited liquid droplets form into the shape of a spherical shaped cap; during the evaporation process, a deposited liquid droplet maintains this geometry until it forms a solid micrometer sized particle. Arrays of solid particles are obtained by sequential translation of the printer stage. The use of DOD inkjet printing for fabrication of discrete particle arrays allows for precise control of particle characteristics (mass, diameter and height), as well as the particle number and spatial distribution on the substrate. The final mass of an individual particle is precisely determined by using gravimetric measurement of the average mass of solution ejected per microdrop. The primary application of this method is fabrication of test materials for the evaluation of spatially-resolved optical and mass spectrometry based sensors used for detecting particle residues of contraband materials, such as explosives or narcotics.
authors.affiliation: National Institute of Standards and Technology, Materials Measurement Laboratory, 100 Bureau Drive, Gaithersburg, MD 20899, USA. greg.gillen@nist.gov.
authors.forename: Greg
authors.initials: G
authors.lastname: Gillen
authors.affiliation: National Institute of Standards and Technology, Materials Measurement Laboratory, 100 Bureau Drive, Gaithersburg, MD 20899, USA. marcela.najarro@nist.gov.
authors.forename: Marcela
authors.initials: M
authors.lastname: Najarro
authors.affiliation: National Institute of Standards and Technology, Materials Measurement Laboratory, 100 Bureau Drive, Gaithersburg, MD 20899, USA. Scott.wight@nist.gov.
authors.forename: Scott
authors.initials: S
authors.lastname: Wight
authors.affiliation: National Institute of Standards and Technology, Materials Measurement Laboratory, 100 Bureau Drive, Gaithersburg, MD 20899, USA. Marlon.walker@nist.gov.
authors.forename: Marlon
authors.initials: M
authors.lastname: Walker
authors.affiliation: National Institute of Standards and Technology, Materials Measurement Laboratory, 100 Bureau Drive, Gaithersburg, MD 20899, USA. Jennifer.verkouteren@nist.gov.
authors.forename: Jennifer
authors.initials: J
authors.lastname: Verkouteren
authors.affiliation: National Institute of Standards and Technology, Materials Measurement Laboratory, 100 Bureau Drive, Gaithersburg, MD 20899, USA. eric.windsor@nist.gov.
authors.forename: Eric
authors.initials: E
authors.lastname: Windsor
authors.affiliation: National Institute of Standards and Technology, Materials Measurement Laboratory, 100 Bureau Drive, Gaithersburg, MD 20899, USA. timothy.barr@nist.gov.
authors.forename: Tim
authors.initials: T
authors.lastname: Barr
authors.affiliation: National Institute of Standards and Technology, Materials Measurement Laboratory, 100 Bureau Drive, Gaithersburg, MD 20899, USA. matthew.staymates@nist.gov.
authors.forename: Matthew
authors.initials: M
authors.lastname: Staymates
authors.affiliation: National Institute of Standards and Technology, Materials Measurement Laboratory, 100 Bureau Drive, Gaithersburg, MD 20899, USA. aaron.urbas@nist.gov.
authors.forename: Aaron
authors.initials: A
authors.lastname: Urbas
mesh_terms: D057927:Hydrophobic and Hydrophilic Interactions; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D009566:Nitrates; D011327:Printing / Q000379:methods*; D012825:Silicon; D013059:Spectrum Analysis, Raman / Q000379:methods*
chemical_list: D009566:Nitrates; C006568:ammonium nitrate; D012825:Silicon
keywords: drop-on-demand; hydrophobic silicon, trace detection; inkjet printing; particle fabrication; sample preparation