Additive manufacturing techniques such as 3D printing are able to generate reproductions of a part in free space without the use of molds; however, the objects produced lack electrical functionality from an applications perspective. At the same time, techniques such as inkjet and laser direct-write (LDW) can be used to print electronic components and connections onto already existing objects, but are not capable of generating a full object on their own. The approach missing to date is the combination of 3D printing processes with direct-write of electronic circuits. Among the numerous direct write techniques available, LDW offers unique advantages and capabilities given its compatibility with a wide range of materials, surface chemistries and surface morphologies. The Naval Research Laboratory (NRL) has developed various LDW processes ranging from the non-phase transformative direct printing of complex suspensions or inks to lase-and-place for embedding entire semiconductor devices. These processes have been demonstrated in digital manufacturing of a wide variety of microelectronic elements ranging from circuit components such as electrical interconnects and passives to antennas, sensors, actuators and power sources. At NRL we are investigating the combination of LDW with 3D printing to demonstrate the digital fabrication of functional parts, such as 3D circuits. Merging these techniques will make possible the development of a new generation of structures capable of detecting, processing, communicating and interacting with their surroundings in ways never imagined before. This paper shows the latest results achieved at NRL in this area, describing the various approaches developed for generating 3D printed electronics with LDW.
Pulse shape discrimination (PSD) is a common method to distinguish between pulses produced by gamma rays and neutrons in scintillator detectors. This technique takes advantage of the property of many scintillators that excitations by recoil protons and electrons produce pulses with different characteristic shapes. Unfortunately, many scintillating materials with good PSD properties have other, undesirable properties such as flammability, toxicity, low availability, high cost, and/or limited size. In contrast, plastic scintillator detectors are relatively low-cost, and easily handled and mass-produced. Recent studies have demonstrated efficient PSD in plastic scintillators using a high concentration of fluorescent dyes. To further investigate the PSD properties of such systems, mixed plastic scintillator samples were produced and tested. The addition of up to 30 wt. % diphenyloxazole (DPO) and other chromophores in polyvinyltoluene (PVT) results in efficient detection with commercial detectors. These plastic scintillators are produced in large diameters up to 4 inches by melt blending directly in a container suitable for in-line detector use. This allows recycling and reuse of materials while varying the compositions. This strategy also avoids additional sample handling and polishing steps required when using removable molds. In this presentation, results will be presented for different mixed-plastic compositions and compared with known scintillating materials
Vapor collection systems, including solid phase microextraction (SPME), require the ability to selectively
collect and concentrate a sample from a large volume of air. In the case of SPME, polymers are needed to
adhere to the fiber for greater reproducibility and longer lasting fibers. The polymerization of carbosilanes
was investigated and produced polymers with molecular weights over 500,000. This polymer class was
then functionalized with hexafluoro-2-propanol (HFIP) end groups that will selectively sorb hydrogen bond
basic vapors. The results of vapor testing with these polymers utilizing a variety of platforms such as
preconcentrators, Surface Acoustic Wave (SAW) sensors, and microcantilevers will be discussed.
We report the successful fabrication of layers of functionalized nanoparticles using a novel infrared, laser-based
deposition technique. A frozen suspension of nanoparticles was ablated with a laser tuned to a vibrational mode of the
solvent, resulting in the disruption of the matrix and ejection of the nanoparticles. The solvent was pumped away and
the nanoparticles collected by a receiving substrate in a conformal process. Photoluminescence measurements of
nanoparticles containing two common dyes showed no significant change to the emission properties of either dye,
suggesting that no damage occurred during the laser ablation process. The process is generally applicable to particles of
various sizes, shapes, and chemistries provided that an appropriate solvent is chosen. Deposition through shadow masks
turned out to be straightforward using this technique, suggesting its potential utility in preparing designer sensor
structures using functionalized nanoparticles.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.