LLNL researchers added unique green solvents (ionic liquids) to an explosive called TATB (1,3,5-triamino-2,4,6-trinitrobenzene) and improved the crystal quality and chemical purity of the material.
This work, supported under the Transformational Materials Initiative (TMI) Laboratory Research and Development project, appears on the cover of the Sept. 1 issue of the journal Physical Chemistry Chemical Physics.
“Improving crystal quality and purity leads to explosive materials that are safer (less likely to react violently) when subjected to mechanical impact or heat,” said Larry Fried, the project’s principal investigator and a co-author of the paper.
Most explosives belong to a general class of materials called molecular crystals, which have become important building blocks in a number of other applications ranging from drugs, pigments, agrochemicals, dyes and optoelectronics. Many of these materials, including TATB, are bound together by a strong network of hydrogen-bonds. This extended network often makes these materials nearly insoluble in common organic solvents, leading to poor quality and limited size crystals, which in turn hinders progress in many technological applications.
So the TMI team looked for a suitable alternative, which happened to be ionic liquids – a special type of molten salt that becomes liquid under the boiling point of water (100 degrees Celsius). Chemists recently became interested in ionic liquids because they are solvents with almost no vapor pressure, and do not evaporate, even under high temperature conditions. They also provide researchers an endless number of choices due to the large combinations of positive and negative ions involved.
To narrow the choices down, lead author Amitesh Maiti used state-of-the-art quantum mechanical simulations to identify a special class of ionic liquids containing fluoride anions that are highly effective in dissolving hydrogen-bonded materials such as TATB. (An anion is an atom with a net negative charge, i.e., more electrons than protons.)
“The design of custom solvents through first principles modeling opens up new possibilities for the dissolution of materials that are hard to dissolve,” Maiti said.
The next step involved an experimental team, led by Phil Pagoria, who was successful not only in dissolving TATB in such solvents, but also in growing large defect-free crystallites (more than 97 percent pure TATB), which will lead to a better formulated material for explosive applications.
The solvents and the dissolution process developed by the TMI team have applications in other fields as well, such as the production of polymers (plastics) or molecular solids (pharmaceuticals, paints, propellants, explosives). For instance, the team found that fluoride ionic liquids are highly effective in dissolving cellulose (plant fiber), a versatile bio-renewable polymeric material with many applications.
However, the immediate goal is to find a cost-effective way to improve the quality of low purity TATB. TATB is an extremely safe explosive that is used by the Department of Energy, the Department of Defense and the mining industry.
Other Livermore researchers include: Alex Gash, Yong Han, Christine Orme and Richard Gee.
Founded in 1952, Lawrence Livermore National Laboratory is a national security laboratory, with a mission to ensure national security and apply science and technology to the important issues of our time. Lawrence Livermore National Laboratory is managed by Lawrence Livermore National Security, LLC for the U.S. Department of Energy's National Nuclear Security Administration.
Anne Stark | EurekAlert!
Hopkins researchers ID neurotransmitter that helps cancers progress
25.04.2019 | Johns Hopkins Medicine
Trigger region found for absence epileptic seizures
25.04.2019 | RIKEN
Flexible, organic and printed electronics conquer everyday life. The forecasts for growth promise increasing markets and opportunities for the industry. In Europe, top institutions and companies are engaged in research and further development of these technologies for tomorrow's markets and applications. However, access by SMEs is difficult. The European project SmartEEs - Smart Emerging Electronics Servicing works on the establishment of a European innovation network, which supports both the access to competences as well as the support of the enterprises with the assumption of innovations and the progress up to the commercialization.
It surrounds us and almost unconsciously accompanies us through everyday life - printed electronics. It starts with smart labels or RFID tags in clothing, we...
The human eye is particularly sensitive to green, but less sensitive to blue and red. Chemists led by Hubert Huppertz at the University of Innsbruck have now developed a new red phosphor whose light is well perceived by the eye. This increases the light yield of white LEDs by around one sixth, which can significantly improve the energy efficiency of lighting systems.
Light emitting diodes or LEDs are only able to produce light of a certain colour. However, white light can be created using different colour mixing processes.
Researchers led by Francesca Ferlaino from the University of Innsbruck and the Austrian Academy of Sciences report in Physical Review X on the observation of supersolid behavior in dipolar quantum gases of erbium and dysprosium. In the dysprosium gas these properties are unprecedentedly long-lived. This sets the stage for future investigations into the nature of this exotic phase of matter.
Supersolidity is a paradoxical state where the matter is both crystallized and superfluid. Predicted 50 years ago, such a counter-intuitive phase, featuring...
A stellar flare 10 times more powerful than anything seen on our sun has burst from an ultracool star almost the same size as Jupiter
A localization phenomenon boosts the accuracy of solving quantum many-body problems with quantum computers which are otherwise challenging for conventional computers. This brings such digital quantum simulation within reach on quantum devices available today.
Quantum computers promise to solve certain computational problems exponentially faster than any classical machine. “A particularly promising application is the...
17.04.2019 | Event News
15.04.2019 | Event News
09.04.2019 | Event News
25.04.2019 | Materials Sciences
25.04.2019 | Earth Sciences
25.04.2019 | Life Sciences