Multi-block polyurethanes via RAFT end-group switching and their characterization by advanced hyphenated techniques

The detailed characterization of poly(styrene)-b-poly(tetrahydrofuran) (pS-b-pTHF) multiblock copolymers (17800 g mol(-1) <= M-n <= 46800 g mol(-1)) generated via urethane linkages is presented. The synthesis of the block copolymers is enabled via a mechanistic switch of the thiocarbonyl thio end group of a poly(styrene) to dihydroxyl terminated polymers that subsequently react with a diisocyanate terminated polytetrahydrofuran based prepolymer to form multiblock copolymer structures. The characterization of the multiblock copolymers and their substructures includes size exclusion chromatography (SEC), liquid chromatography at critical conditions (LCCC), nuclear magnetic resonance (NMR), and infrared (IR) spectroscopy as well as matrix-assisted laser desorption/ionization (MALDI) mass spectrometry. To obtain even further details of the polymer size and its composition, SEC with triple detection as well as newly developed SEC coupled online to IR spectroscopy was carried out. The quantification of the average block fractions via online SEC-IR (41-61 mol % pTHF) is in very good agreement with the results obtained via NMR spectroscopy (39-66 mol % pTHF)

DARWIN: towards the ultimate dark matter detector

DARk matter WImp search with liquid xenoN (DARWIN) will be an experiment forthe direct detection of dark matter using a multi-ton liquid xenon timeprojection chamber at its core. Its primary goal will be to explore theexperimentally accessible parameter space for Weakly Interacting MassiveParticles (WIMPs) in a wide mass-range, until neutrino interactions with thetarget become an irreducible background. The prompt scintillation light and thecharge signals induced by particle interactions in the xenon will be observedby VUV sensitive, ultra-low background photosensors. Besides its excellentsensitivity to WIMPs above a mass of 5 GeV/c2, such a detector with its largemass, low-energy threshold and ultra-low background level will also besensitive to other rare interactions. It will search for solar axions, galacticaxion-like particles and the neutrinoless double-beta decay of 136-Xe, as wellas measure the low-energy solar neutrino flux with <1% precision, observecoherent neutrino-nucleus interactions, and detect galactic supernovae. Wepresent the concept of the DARWIN detector and discuss its physics reach, themain sources of backgrounds and the ongoing detector design and R&D efforts

Multi-Block Polyurethanes via RAFT End-Group Switching and Their Characterization by Advanced Hyphenated Techniques

The detailed characterization of poly­(styrene)-<i>b</i>-poly­(tetrahydrofuran) (pS-<i>b</i>-pTHF) multiblock copolymers (17800 g mol^–1≤ <i>M</i>_n ≤ 46800 g mol^–1) generated via urethane linkages is presented. The synthesis of the block copolymers is enabled via a mechanistic switch of the thiocarbonyl thio end group of a poly­(styrene) to dihydroxyl terminated polymers that subsequently react with a diisocyanate terminated polytetrahydrofuran based prepolymer to form multiblock copolymer structures. The characterization of the multiblock copolymers and their substructures includes size exclusion chromatography (SEC), liquid chromatography at critical conditions (LCCC), nuclear magnetic resonance (NMR), and infrared (IR) spectroscopy as well as matrix-assisted laser desorption/ionization (MALDI) mass spectrometry. To obtain even further details of the polymer size and its composition, SEC with triple detection as well as newly developed SEC coupled online to IR spectroscopy was carried out. The quantification of the average block fractions via online SEC-IR (41–61 mol % pTHF) is in very good agreement with the results obtained via NMR spectroscopy (39–66 mol % pTHF)