Science & Technology - 2016
August
NIF Ultrathin Polymer Film Is an R&D 100 Finalist
A robust, scalable method of fabricating freestanding polymer films that are larger, stronger and thinner than conventionally produced films has been named a 2016 R&D 100 finalist. R&D 100 awards recognize the most revolutionary technologies introduced to the market in a given year. This year’s R&D 100 winners will be announced at an awards dinner on Nov. 3 in Washington, D.C.
The polyelectrolyte enabled liftoff (PEEL) technology is used for the daily fabrication of membranes as thin as 30 nanometers that serve as compliant, load-bearing elements known as “tents” for suspending target capsules inside NIF hohlraums. The ability to fabricate films below 45 nanometers has enabled NIF researchers to directly verify that the film thickness of the tents can affect the performance of imploding fuel capsules in unexpected ways (see “Studying Effects of Target ‘Tents’ on NIF Implosions”).
A stainless steel ball is supported by a thin sheet of plastic about 200 atoms thick produced using the polyelectrolyte enabled liftoff (PEEL) technology. The polymer is stretched across a five-millimeter hoop, a distance of more than 300,000 times its thickness; the steel ball weighs more than 80,000 times more than the polymer film. Because the PEEL process is easily scalable in size and manufacturing quantity, it could be applied to sensing, catalysis, filtration and wound-healing applications. The work, which was funded by the Laboratory Directed Research and Development (LDRD) program, was performed by LLNL researchers Michael Stadermann, Salmaan Baxamusa, Philip Miller, Tayyab Suratwala, Chantel Aracne-Ruddle, and Art Nelson in collaboration with General Atomics researchers Anatolios Tambazidis and Kelly Youngblood; former LLNL summer students Maverick Chea and Shuaili Li; and former LLNL postdoc William Floyd.
Films fabricated with PEEL can be as thin as six nanometers (less than 30 atoms thick) and are capable of bearing loads ranging from milligrams to grams and deformations of greater than 40 percent. The technology employs robust, water-based, and self-optimizing surface chemistry to fabricate ultrathin films 100 square centimeters or more in area. The process is applicable to a variety of polymeric materials.
PEEL provides an alternative to free-standing thin film fabrication processes that use a sacrificial interlayer, accessing thicknesses and areas that are not accessible by current technologies. PEEL-produced freestanding films are stronger, thinner, and can cover larger areas than those that use the sacrificial interlayer.
PEEL can be used as an industrially scalable membrane fabrication process for filtration, sensing, catalysis, or biomedical applications. For example, reverse osmosis filtration membranes are ultrathin free-standing polymer films that must be manufactured in large quantities. Technologies such as interfacial polymerization, in which there is no deposition substrate, must be used because liftoff is unreliable at the required film thinness. Controlling film thickness in interfacial polymerization can be challenging, and the chemical requirements of this process limit the types of polymer films that can be used as filtration membranes. Utilizing PEEL would lift these limitations, allowing membrane scientists to expand the available material set as well as more carefully control film thickness.
For more information, view the video (registration required).
Take a Virtual Tour of NIF
Break out your smartphone, fire up your YouTube app, and strap on your virtual reality headset to take an immersive guided tour of the world’s largest and highest-energy laser facility.
A new VR video, available here (youtu.be/j_snOFH2K7A), takes you into the target fabrication facility, where NIF’s ultra-precision targets are assembled; the Target Bay, which served as the set for the warp core of the Starship Enterprise in the “Star Trek: Into Darkness” film; the Control Room, where operators count down for a shot; the Laser Bay, where a tiny initial laser pulse is amplified by one million billion times; and inside the Target Chamber, where the lasers converge on the target and produce temperatures and pressures comparable to the center of a star or a giant planet.
Here’s a 360-degree desktop/mobile version of the video:
