Ionic liquids with coordinating anions can break up the hydrogen bond network of PPTA oligomers. Phosphonium ionic liquids were found to be the strongest solvents enabling them to be possible alternatives for the synthesis of PPTA.

Several ionic liquids (ILs) were tested for their suitability to synthesize the aramid polymer PPTA in an attempt to diminish the dependence on the toxic N-methylpyrrolidone (NMP) that is currently used in industry. The room-temperature IL 3-methyl-1-octylimidazolium chloride ([C8MIM][Cl]) showed the highest promise as with this medium the polycondensation reaction proceeds with a similar mechanism as it happens in the solvent mixture of NMP with CaCl2.With this IL, PPTA polymer with an inherent viscosity of 1.95 dL/g was obtained in a lowtemperature polycondensation reaction. This is the highest reported molecular mass of PPTA to date that was obtained by polymerization in an ionic liquid. An EXAFS and solid state NMR spectroscopic study showed that [C8MIM][Cl] and the current industrial solvent of NMP and CaCl2 show similar characteristics when it comes to the synthesis of PPTA.

Ionic liquids, imidazolium chloride, PPTA, aramids, N-methylpyrrolidone, hydrogen bonds 1-Octyl-3-methylimidazolium chloride ([C8MIM][Cl]) shows the greatest potential to replace N-methylpyrrolidone/CaCl2 as solvent for the synthesis of poly-p-phenylene terephthalamide (PPTA), a high-strength material when spun into a fibre. Coordinating anions are crucial to prevent precipitation of the polymer during synthesis. Additionally, the imidazolium cations play an essential role in gelation of the reaction mixture and enable the polycondensation reaction to continue in a gel-state. Analysis of Kamlet-Taft parameters and Gutmann donor and acceptor numbers of ionic liquids and various solvents showed that balanced interactions between the secondary amide bonds of the polymer, anion, cation and solvent are required to form a network of hydrogen bond interactions throughout the reaction mixture. This hypothesis was supported by the fact that tri-n-butyl phosphate (TBP), containing similar Kamlet-Taft and Gutmann solvent parameters as N-methylpyrrolidone, was able to produce PPTA with an inherent

The polymeric binder of bonded NdFeB magnets can be dissolved in ionic liquids with strongly coordinating anions and the magnetic powder can be reused for manufacturing of new magnets.

In order to improve the characteristics of future integrated circuits, low dielectric constant (low-k) materials are employed. In this paper we describe in detail the characteristics of k = 2.0, SICOH films treated by capacitively coupled Ar/N2 and Ar/H2 plasmas, which were applied in order to modify the top surface of the film. New insights were obtained about the porous structure of the pristine and the plasma treated films: analyses indicated that the investigated plasma treatments reduced the pore size in the top ten nm of the films, while partial carbon depletion was found down to a few tens of nm inside the film. For the integration of metal barriers deposited by Atomic Layer Deposition in interconnect technologies, precursor penetration into the porous low-k dielectric should be avoided. We investigated precursor penetration in the pores during TaN Atomic Layer Deposition on the pristine and the plasma treated porous low-k films. Detailed analyses showed that the plasma induced modifications resulted in a local growth enhancement and pore sealing during the first cycles of the atomic layer deposition process.

To achieve very low permittivity values, advanced generations of low-k dielectrics for interconnects have a porous structure. Precursor penetration during metal barrier deposition by atomic layer deposition needs to be avoided not to degrade the low-k material properties. In this paper, we compare various options to seal a highly porous low-k material with a k-value of 2.0 against penetration during TaN ALD. This includes the exploration of a higher deposition temperature, the use of additional sealing layers, and the introduction of a short PVD Ta flash exposure prior to ALD. Depending on the technique used, pore penetration can be quasi completely avoided.

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