Hydrogels, based on polymerized ionic liquids, are increasingly used in the medical and pharmaceutical industry as implants, drug delivery systems, contact lens material, bone substitutes and stent ...coatings. Therefore they need to be biocompatible, flexible and resistant to external stress. In order to meet these requirements, there is a large interest in design, synthesis and characterization of these interesting polymers. In this work, mechanical properties such as gelation kinetics, shear strain resistance, and response to compression and stretching of ten different polymerized ionic liquid-based hydrogels were examined, completing the picture of the rheological behavior of these materials. Interestingly, the investigations of stretching measurements showed a wide range of critical strains leading to failure from 4.8 ± 1.1 to 47.9 ± 15.1%and in compression measurements critical strain from 7.8 ± 3.6 to higher than 59.8 ± 17.3%, as well as a linear viscoelastic range in shear from 14 ± 8 to 267 ± 26%. These results allow improved design with a “choose-the-best-material”-toolbox for medical applications.
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•Large variety of hydrogels based on ionic liquids.•Chemical structure of the monomers influences the gelation time of the hydrogel.•Amplitude sweep measurements.•Counterion of the charged polymer backbone influences the storage modulus.•Compression and tensile tests.
Cryogenic semiconductor detectors operated at temperatures below 100 mK are commonly used in particle physics experiments searching for dark matter. The largest such germanium and silicon detectors, ...with diameters of 100 mm and thickness of 33 mm, are planned for use by the Super Cryogenic Dark Matter Search (SuperCDMS) experiment at SNOLAB, Canada. Still larger individual detectors are being investigated to scale up the sensitive mass of future experiments. We present here the first results of testing two prototype 150 mm diameter silicon ionization detectors. The detectors are 25 mm and 33 mm thick with masses 1.7 and 2.2 times larger than those currently planned for SuperCDMS. These devices were operated with contact-free bias electrodes to minimize leakage currents which currently limit operation at high bias voltages. The results show promise for the use of such technologies in solid state cryogenic detectors.
A dedicated facility has been commissioned for Cryogenic Dark Matter Search (CDMS) detector fabrication at Texas A&M University (TAMU). The fabrication process has been carefully tuned using this ...facility and its equipment. Production of successfully tested detectors has been demonstrated. Significant improvements in detector performance have been made using new fabrication methods/equipment and tuning of process parameters.
We report the first demonstration of a phonon-mediated silicon detector technology that provides a primary phonon measurement in a low-voltage region, and a simultaneous indirect measurement of the ...ionization signal through Neganov–Trofimov–Luke amplification in a high voltage region, both in a monolithic crystal. We present characterization of charge and phonon transport between the two stages of the detector and the resulting background discrimination capability at low energies. This new detector technology has the potential to significantly enhance the sensitivity of dark matter and coherent neutrino scattering experiments beyond the capabilities of current technologies that have limited discrimination at low energies.
We present limits on spin-independent dark matter-nucleon interactions using a 10.6 g Si athermal phonon detector with a baseline energy resolution of σE = 3.86 ± 0.04 ( stat ) +0.19 −0.00 ( syst ) ...eV . This exclusion analysis sets the most stringent dark matter-nucleon scattering cross-section limits achieved by a cryogenic detector for dark matter particle masses from 93 to 140 MeV / c2 , with a raw exposure of 9.9 g d acquired at an above-ground facility. This work illustrates the scientific potential of detectors with athermal phonon sensors with eV-scale energy resolution for future dark matter searches.
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