@article{ZhaoOpitzEljarratetal.2021, author = {Zhao, Yuhang and Opitz, Andreas and Eljarrat, Alberto and Kochovski, Zdravko and Koch, Christoph and Koch, Norbert and Lu, Yan}, title = {Kinetic study on the adsorption of 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane on Ag nanoparticles in chloroform}, series = {ACS applied nano materials}, volume = {4}, journal = {ACS applied nano materials}, number = {11}, publisher = {American Chemical Society}, address = {Washington}, issn = {2574-0970}, doi = {10.1021/acsanm.1c02153}, pages = {11625 -- 11635}, year = {2021}, abstract = {In this study, the kinetics of the adsorption of 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F(4)TCNQ) on the surface of Ag nanoparticles (Ag NPs) in chloroform has been intensively investigated, as molecular doping is known to play a crucial role in organic electronic devices. Based on the results obtained from UV-visible (vis)-near-infrared (NIR) absorption spectroscopy, cryogenic transmission electron microscopy, scanning nanobeam electron diffraction, and electron energy loss spectroscopy, a two-step interaction kinetics has been proposed for the Ag NPs and F(4)TCNQ molecules, which includes the first step of electron transfer from Ag NPs to F(4)TCNQ indicated by the ionization of F(4)TCNQ and the second step of the formation of a Ag-F(4)TCNQ complex. The whole process has been followed via UV-vis-NIR absorption spectroscopy, which reveals distinct kinetics at two stages: the instantaneous ionization and the long-term complex formation. The kinetics and the influence of the molar ratio of Ag NPs/F(4)TCNQ molecules on the interaction between Ag NPs and F(4)TCNQ molecules in an organic solution are reported herein for the first time. Furthermore, the control experiment with silica-coated Ag NPs manifests that the charge transfer at the surface between Ag NPs and F(4)TCNQ molecules is prohibited by a silica layer of 18 nm.}, language = {en} } @article{ZhouXuMaetal.2021, author = {Zhou, Shuo and Xu, Xun and Ma, Nan and Jung, Friedrich and Lendlein, Andreas}, title = {Influence of sterilization conditions on sulfate-functionalized polyGGE}, series = {Clinical hemorheology and microcirculation : blood flow and vessels}, volume = {79}, journal = {Clinical hemorheology and microcirculation : blood flow and vessels}, number = {4}, publisher = {IOS Press}, address = {Amsterdam}, issn = {1386-0291}, doi = {10.3233/CH-211241}, pages = {597 -- 608}, year = {2021}, abstract = {Sulfated biomolecules are known to influence numerous biological processes in all living organisms. Particularly, they contribute to prevent and inhibit the hypercoagulation condition. The failure of polymeric implants and blood contacting devices is often related to hypercoagulation and microbial contamination. Here, bioactive sulfated biomacromolecules are mimicked by sulfation of poly(glycerol glycidyl ether) (polyGGE) films. Autoclaving, gamma-ray irradiation and ethylene oxide (EtO) gas sterilization techniques were applied to functionalized materials. The sulfate group density and hydrophilicity of sulfated polymers were decreased while chain mobility and thermal degradation were enhanced post autoclaving when compared to those after EtO sterilization. These results suggest that a quality control after sterilization is mandatory to ensure the amount and functionality of functionalized groups are retained.}, language = {en} } @phdthesis{Mostafa2024, author = {Mostafa, Amr}, title = {DNA origami nanoforks: A platform for cytochrome c single molecule surface enhanced Raman spectroscopy}, doi = {10.25932/publishup-63548}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-635482}, school = {Universit{\"a}t Potsdam}, pages = {xi, 90, x}, year = {2024}, abstract = {This thesis presents a comprehensive exploration of the application of DNA origami nanofork antennas (DONAs) in the field of spectroscopy, with a particular focus on the structural analysis of Cytochrome C (CytC) at the single-molecule level. The research encapsulates the design, optimization, and application of DONAs in enhancing the sensitivity and specificity of Raman spectroscopy, thereby offering new insights into protein structures and interactions. The initial phase of the study involved the meticulous optimization of DNA origami structures. This process was pivotal in developing nanoscale tools that could significantly enhance the capabilities of Raman spectroscopy. The optimized DNA origami nanoforks, in both dimer and aggregate forms, demonstrated an enhanced ability to detect and analyze molecular vibrations, contributing to a more nuanced understanding of protein dynamics. A key aspect of this research was the comparative analysis between the dimer and aggregate forms of DONAs. This comparison revealed that while both configurations effectively identified oxidation and spin states of CytC, the aggregate form offered a broader range of detectable molecular states due to its prolonged signal emission and increased number of molecules. This extended duration of signal emission in the aggregates was attributed to the collective hotspot area, enhancing overall signal stability and sensitivity. Furthermore, the study delved into the analysis of the Amide III band using the DONA system. Observations included a transient shift in the Amide III band's frequency, suggesting dynamic alterations in the secondary structure of CytC. These shifts, indicative of transitions between different protein structures, were crucial in understanding the protein's functional mechanisms and interactions. The research presented in this thesis not only contributes significantly to the field of spectroscopy but also illustrates the potential of interdisciplinary approaches in biosensing. The use of DNA origami-based systems in spectroscopy has opened new avenues for research, offering a detailed and comprehensive understanding of protein structures and interactions. The insights gained from this research are expected to have lasting implications in scientific fields ranging from drug development to the study of complex biochemical pathways. This thesis thus stands as a testament to the power of integrating nanotechnology, biochemistry, and spectroscopic techniques in addressing complex scientific questions.}, language = {en} } @article{MichaelisAengenheisterTuchtenhagenetal.2022, author = {Michaelis, Vivien and Aengenheister, Leonie and Tuchtenhagen, Max and Rinklebe, J{\"o}rg and Ebert, Franziska and Schwerdtle, Tanja and Buerki-Thurnherr, Tina and Bornhorst, Julia}, title = {Differences and interactions in placental manganese and iron transfer across an in vitro model of human villous trophoblasts}, series = {International journal of molecular sciences}, volume = {23}, journal = {International journal of molecular sciences}, number = {6}, publisher = {MDPI}, address = {Basel}, issn = {1422-0067}, doi = {10.3390/ijms23063296}, pages = {18}, year = {2022}, abstract = {Manganese (Mn) as well as iron (Fe) are essential trace elements (TE) important for the maintenance of physiological functions including fetal development. However, in the case of Mn, evidence suggests that excess levels of intrauterine Mn are associated with adverse pregnancy outcomes. Although Mn is known to cross the placenta, the fundamentals of Mn transfer kinetics and mechanisms are largely unknown. Moreover, exposure to combinations of TEs should be considered in mechanistic transfer studies, in particular for TEs expected to share similar transfer pathways. Here, we performed a mechanistic in vitro study on the placental transfer of Mn across a BeWo b30 trophoblast layer. Our data revealed distinct differences in the placental transfer of Mn and Fe. While placental permeability to Fe showed a clear inverse dose-dependency, Mn transfer was largely independent of the applied doses. Concurrent exposure of Mn and Fe revealed transfer interactions of Fe and Mn, indicating that they share common transfer mechanisms. In general, mRNA and protein expression of discussed transporters like DMT1, TfR, or FPN were only marginally altered in BeWo cells despite the different exposure scenarios highlighting that Mn transfer across the trophoblast layer likely involves a combination of active and passive transport processes.}, language = {en} } @misc{BandeGonzalezKlamrothetal.2022, author = {Bande, Annika and Gonz{\´a}lez, Leticia and Klamroth, Tillmann and Tremblay, Jean Christophe}, title = {Theoretical chemistry and quantum dynamics at interfaces}, series = {Chemical physics : a journal devoted to experimental and theoretical research involving problems of both a chemical and physical nature}, volume = {558}, journal = {Chemical physics : a journal devoted to experimental and theoretical research involving problems of both a chemical and physical nature}, publisher = {Elsevier Science}, address = {Amsterdam [u.a.]}, issn = {0301-0104}, doi = {10.1016/j.chemphys.2022.111509}, pages = {3}, year = {2022}, language = {en} } @article{CrovettoKojdaYietal.2022, author = {Crovetto, Andrea and Kojda, Danny and Yi, Feng and Heinselman, Karen N. and LaVan, David A. and Habicht, Klaus and Unold, Thomas and Zakutayev, Andriy}, title = {Crystallize It before It diffuses}, series = {Journal of the american chemical society}, volume = {144}, journal = {Journal of the american chemical society}, number = {29}, publisher = {American Chemical Society}, address = {Washington}, issn = {0002-7863}, doi = {10.1021/jacs.2c04868}, pages = {13334 -- 13343}, year = {2022}, abstract = {Numerous phosphorus-rich metal phosphides containing both P-P bonds and metal-P bonds are known from the solid-state chemistry literature. A method to grow these materials in thin-film form would be desirable, as thin films are required in many applications and they are an ideal platform for high-throughput studies. In addition, the high density and smooth surfaces achievable in thin films are a significant advantage for characterization of transport and optical properties. Despite these benefits, there is hardly any published work on even the simplest binary phosphorus-rich phosphide films. Here, we demonstrate growth of single-phase CuP2 films by a two-step process involving reactive sputtering of amorphous CuP2+x and rapid annealing in an inert atmosphere. At the crystallization temperature, CuP2 is thermodynamically unstable with respect to Cu3P and P-4. However, CuP2 can be stabilized if the amorphous precursors are mixed on the atomic scale and are sufficiently close to the desired composition (neither too P poor nor too P rich). Fast formation of polycrystalline CuP2, combined with a short annealing time, makes it possible to bypass the diffusion processes responsible for decomposition. We find that thin-film CuP2 is a 1.5 eV band gap semiconductor with interesting properties, such as a high optical absorption coefficient (above 10(5) cm(-1)), low thermal conductivity (1.1 W/(K m)), and composition-insensitive electrical conductivity (around 1 S/cm). We anticipate that our processing route can be extended to other phosphorus-rich phosphides that are still awaiting thin-film synthesis and will lead to a more complete understanding of these materials and of their potential applications.}, language = {en} } @article{TungMaringXuetal.2022, author = {Tung, Wing Tai and Maring, Janita A. and Xu, Xun and Liu, Yue and Becker, Matthias and Somesh, Dipthi Bachamanda and Klose, Kristin and Wang, Weiwei and Sun, Xianlei and Ullah, Imran and Kratz, Karl and Neffe, Axel T. and Stamm, Christof and Ma, Nan and Lendlein, Andreas}, title = {In vivo performance of a cell and factor free multifunctional fiber mesh modulating postinfarct myocardial remodeling}, series = {Advanced Functional Materials}, volume = {32}, journal = {Advanced Functional Materials}, number = {31}, publisher = {Wiley}, address = {Weinheim}, issn = {1616-301X}, doi = {10.1002/adfm.202110179}, pages = {17}, year = {2022}, abstract = {Guidance of postinfarct myocardial remodeling processes by an epicardial patch system may alleviate the consequences of ischemic heart disease. As macrophages are highly relevant in balancing immune response and regenerative processes their suitable instruction would ensure therapeutic success. A polymeric mesh capable of attracting and instructing monocytes by purely physical cues and accelerating implant degradation at the cell/implant interface is designed. In a murine model for myocardial infarction the meshes are compared to those either coated with extracellular matrix or loaded with induced cardiomyocyte progenitor cells. All implants promote macrophage infiltration and polarization in the epicardium, which is verified by in vitro experiments. 6 weeks post-MI, especially the implantation of the mesh attenuates left ventricular adverse remodeling processes as shown by reduced infarct size (14.7\% vs 28-32\%) and increased wall thickness (854 mu m vs 400-600 mu m), enhanced angiogenesis/arteriogenesis (more than 50\% increase compared to controls and other groups), and improved heart function (ejection fraction = 36.8\% compared to 12.7-31.3\%). Upscaling as well as process controls is comprehensively considered in the presented mesh fabrication scheme to warrant further progression from bench to bedside.}, language = {en} } @article{BreternitzSchorr2021, author = {Breternitz, Joachim and Schorr, Susan}, title = {Symmetry relations in wurtzite nitrides and oxide nitrides and the curious case of Pmc2(1)}, series = {Acta crystallographica / International Union of Crystallography. Section A, Foundations and advances}, volume = {77}, journal = {Acta crystallographica / International Union of Crystallography. Section A, Foundations and advances}, number = {3}, publisher = {Blackwell}, address = {Oxford [u.a.]}, issn = {2053-2733}, doi = {10.1107/S2053273320015971}, pages = {208 -- 216}, year = {2021}, abstract = {Binary III-V nitrides such as AlN, GaN and InN in the wurtzite-type structure have long been considered as potent semiconducting materials because of their optoelectronic properties, amongst others. With rising concerns over the utilization of scarce elements, a replacement of the trivalent cations by others in ternary and multinary nitrides has led to the development of different variants of nitrides and oxide nitrides crystallizing in lower-symmetry variants of wurtzite. This work presents the symmetry relationships between these structural types specific to nitrides and oxide nitrides and updates some prior work on this matter. The non-existence of compounds crystallizing in Pmc2(1), formally the highest subgroup of the wurtzite type fulfilling Pauling's rules for 1:1:2 stoichiometries, has been puzzling scientists for a while; a rationalization is given, from a crystallographic basis, of why this space group is unlikely to be adopted.}, language = {en} } @article{MeiSiebertXuetal.2022, author = {Mei, Shilin and Siebert, Andreas and Xu, Yaolin and Quan, Ting and Garcia-Diez, Raul and B{\"a}r, Marcus and H{\"a}rtel, Paul and Abendroth, Thomas and D{\"o}rfler, Susanne and Kaskel, Stefan and Lu, Yan}, title = {Large-Scale Synthesis of Nanostructured Carbon-Ti4O7 Hollow Particles as Efficient Sulfur Host Materials for Multilayer Lithium-Sulfur Pouch Cells}, series = {Batteries \& supercaps}, volume = {5}, journal = {Batteries \& supercaps}, number = {6}, publisher = {Wiley-VCH}, address = {Weinheim}, issn = {2566-6223}, doi = {10.1002/batt.202100398}, pages = {11}, year = {2022}, abstract = {Applications of advanced cathode materials with well-designed chemical components and/or optimized nanostructures promoting the sulfur redox kinetics and suppressing the shuttle effect of polysulfides are highly valued. However, in the case of actual lithium-sulfur (Li-S) batteries under practical working conditions, one long-term obstacle still exists, which is mainly due to the difficulties in massive synthesis of such nanomaterials with low cost and ease of control on the nanostructure. Herein, we develop a facile synthesis of carbon coated Ti4O7 hollow nanoparticles (Ti4O7) using spherical polymer electrolyte brush as soft template, which is scalable via utilizing a minipilot reactor. The C Ti4O7 hollow nanoparticles provide strong chemical adsorption to polysulfides through the large polar surface and additional physical confinement by rich micro- \& mesopores and have successfully been employed as an efficient sulfur host for multilayer pouch cells. Besides, the sluggish kinetics of the sulfur and lithium sulfide redox mechanism can be improved by the highly conductive Ti4O7 via catalyzation of the conversion of polysulfides. Consequently, the C-Ti4O7 based pouch cell endows a high discharge capacity of 1003 mAhg(-1) at 0.05 C, a high-capacity retention of 83.7\% after 100 cycles at 0.1 C, and a high Coulombic efficiency of 97.5\% at the 100th cycle. This work proposes an effective approach to transfer the synthesis of hollow Ti4O7 nanoparticles from lab- to large-scale production, paving the way to explore a wide range of advanced nanomaterials for multilayer Li-S pouch cells.}, language = {en} } @article{LepreHeskeNowakowskietal.2022, author = {Lepre, Enrico and Heske, Julian and Nowakowski, Michal and Scoppola, Ernesto and Zizak, Ivo and Heil, Tobias and K{\"u}hne, Thomas D. and Antonietti, Markus and Lopez-Salas, Nieves and Albero, Josep}, title = {Ni-based electrocatalysts for unconventional CO2 reduction reaction to formic acid}, series = {Nano energy}, volume = {97}, journal = {Nano energy}, publisher = {Elsevier}, address = {Amsterdam}, issn = {2211-2855}, doi = {10.1016/j.nanoen.2022.107191}, pages = {12}, year = {2022}, abstract = {Electrochemical reduction stands as an alternative to revalorize CO2. Among the different alternatives, Ni single atoms supported on carbonaceous materials are an appealing catalytic solution due to the low cost and versatility of the support and the optimal usage of Ni and its predicted selectivity and efficiency (ca. 100\% towards CO). Herein, we have used noble carbonaceous support derived from cytosine to load Ni subnanometric sites. The large heteroatom content of the support allows the stabilization of up to 11 wt\% of Ni without the formation of nanoparticles through a simple impregnation plus calcination approach, where nickel promotes the stabilization of C3NOx frameworks and the oxidative support promotes a high oxidation state of nickel. EXAFS analysis points at nickel single atoms or subnanometric clusters coordinated by oxygen in the material surface. Unlike the wellknown N-coordinated Ni single sites selectivity towards CO2 reduction, O-coordinated-Ni single sites (ca. 7 wt\% of Ni) reduced CO2 to CO, but subnanometric clusters (11 wt\% of Ni) foster the unprecedented formation of HCOOH with 27\% Faradaic efficiency at - 1.4 V. Larger Ni amounts ended up on the formation of NiO nanoparticles and almost 100\% selectivity towards hydrogen evolution.}, language = {en} } @article{HaubitzDrobotTsushimaetal.2021, author = {Haubitz, Toni and Drobot, Bj{\"o}rn and Tsushima, Satoru and Steudtner, Robin and Stumpf, Thorsten and Kumke, Michael Uwe}, title = {Quenching mechanism of uranyl(VI) by chloride and bromide in aqueous and non-aqueous solutions}, series = {The journal of physical chemistry : A, Molecules, spectroscopy, kinetics, environment \& general theory}, volume = {125}, journal = {The journal of physical chemistry : A, Molecules, spectroscopy, kinetics, environment \& general theory}, number = {20}, publisher = {American Chemical Society}, address = {Washington}, issn = {1089-5639}, doi = {10.1021/acs.jpca.1c02487}, pages = {4380 -- 4389}, year = {2021}, abstract = {A major hindrance in utilizing uranyl(VI) luminescence as a standard analytical tool, for example, in environmental monitoring or nuclear industries, is quenching by other ions such as halide ions, which are present in many relevant matrices of uranyl(VI) speciation. Here, we demonstrate through a combination of time-resolved laser-induced fluorescence spectroscopy, transient absorption spectroscopy, and quantum chemistry that coordinating solvent molecules play a crucial role in U(VI) halide luminescence quenching. We show that our previously suggested quenching mechanism based on an internal redox reaction of the 1:2-uranyl-halide-complex holds also true for bromide-induced quenching of uranyl(VI). By adopting specific organic solvents, we were able to suppress the separation of the oxidized halide ligand X-2(center dot-) and the formed uranyl(V) into fully solvated ions, thereby "reigniting" U(VI) luminescence. Time-dependent density functional theory calculations show that quenching occurs through the outer-sphere complex of U(VI) and halide in water, while the ligand-to-metal charge transfer is strongly reduced in acetonitrile.}, language = {en} } @article{PhamQuanMeietal.2022, author = {Pham, Duong Tung and Quan, Ting and Mei, Shilin and Lu, Yan}, title = {Colloidal metal sulfide nanoparticles for high performance electrochemical energy storage systems}, series = {Current opinion in green and sustainable chemistry}, volume = {34}, journal = {Current opinion in green and sustainable chemistry}, publisher = {Elsevier}, address = {Amsterdam}, issn = {2452-2236}, doi = {10.1016/j.cogsc.2022.100596}, pages = {11}, year = {2022}, abstract = {Transition metal sulfides have emerged as excellent replacement candidates of traditional insertion electrode materials based on their conversion or alloying mechanisms, facilitating high specific capacity and rate ability. However, parasitic reactions such as massive volume change during the discharge/ charge processes, intermediate polysulfide dissolution, and passivating solid electrolyte interface formation have led to poor cyclability, hindering their feasibility and applicability in energy storage systems. Colloidal metal sulfide nanoparticles, a special class that integrates the intrinsic chemical properties of metal sulfides and their specified structural features, have fairly enlarged their contribution due to the synergistic effect. This review highlights the latest synthetic approaches based on colloidal process. Their corresponding electrochemical outcomes will also be discussed, which are thoroughly updated along with their insight scientific standpoints.}, language = {en} } @article{ReitenbachGeigerWangetal.2023, author = {Reitenbach, Julija and Geiger, Christina and Wang, Peixi and Vagias, Apostolos N. and Cubitt, Robert and Schanzenbach, Dirk and Laschewsky, Andr{\´e} and Papadakis, Christine M. and M{\"u}ller-Buschbaum, Peter}, title = {Effect of magnesium salts with chaotropic anions on the swelling behavior of PNIPMAM thin films}, series = {Macromolecules : a publication of the American Chemical Society}, volume = {56}, journal = {Macromolecules : a publication of the American Chemical Society}, number = {2}, publisher = {American Chemical Society}, address = {Washington}, issn = {0024-9297}, doi = {10.1021/acs.macromol.2c02282}, pages = {567 -- 577}, year = {2023}, abstract = {Poly(N-isopropylmethacrylamide) (PNIPMAM) is a stimuli responsive polymer, which in thin film geometry exhibits a volume-phase transition upon temperature increase in water vapor. The swelling behavior of PNIPMAM thin films containing magnesium salts in water vapor is investigated in view of their potential application as nanodevices. Both the extent and the kinetics of the swelling ratio as well as the water content are probed with in situ time-of-flight neutron reflectometry. Additionally, in situ Fourier-transform infrared (FTIR) spectroscopy provides information about the local solvation of the specific functional groups, while two-dimensional FTIR correlation analysis further elucidates the temporal sequence of solvation events. The addition of Mg(ClO4)2 or Mg(NO3)2 enhances the sensitivity of the polymer and therefore the responsiveness of switches and sensors based on PNIPMAM thin films. It is found that Mg(NO3)2 leads to a higher relative water uptake and therefore achieves the highest thickness gain in the swollen state.}, language = {en} } @inproceedings{BreternitzSchorr2021, author = {Breternitz, Joachim and Schorr, Susan}, title = {Halide perovskites}, series = {Acta crystallographica / International Union of Crystallography. Section A, Foundations and advances}, volume = {77}, booktitle = {Acta crystallographica / International Union of Crystallography. Section A, Foundations and advances}, number = {Suppl.}, publisher = {Blackwell}, address = {Oxford [u.a.]}, issn = {2053-2733}, pages = {C750 -- C750}, year = {2021}, language = {en} } @article{NchiozemNgnitedemSperlichMatietaetal.2023, author = {Nchiozem-Ngnitedem, Vaderament-Alexe and Sperlich, Eric and Matieta, Valaire Yemene and Kuete, Jenifer Reine Ngnouzouba and Kuete, Victor and Omer, Ejlal A. A. and Efferth, Thomas and Schmidt, Bernd}, title = {Synthesis and bioactivity of isoflavones from ficus carica and some non-natural analogues}, series = {Journal of natural products : Lloydia}, volume = {86}, journal = {Journal of natural products : Lloydia}, number = {6}, publisher = {American Chemical Society}, address = {Washington, DC}, issn = {0163-3864}, doi = {10.1021/acs.jnatprod.3c00219}, pages = {1520 -- 1528}, year = {2023}, abstract = {FicucariconeD (1) and its 4 '-demethyl congener 2 are isoflavones isolated from fruits of Ficus carica that share a 5,7-dimethoxy-6-prenyl-substituted A-ring. Both naturalproducts were, for the first time, obtained by chemical synthesisin six steps, starting from 2,4,6-trihydroxyacetophenone. Key stepsare a microwave-promoted tandem sequence of Claisen- and Cope-rearrangementsto install the 6-prenyl substituent and a Suzuki-Miyaura crosscoupling for installing the B-ring. By using various boronic acids,non-natural analogues become conveniently available. All compoundswere tested for cytotoxicity against drug-sensitive and drug-resistanthuman leukemia cell lines, but were found to be inactive. The compoundswere also tested for antimicrobial activities against a panel of eightGram-negative and two Gram-positive bacterial strains. Addition ofthe efflux pump inhibitor phenylalanine-arginine-beta-naphthylamide(PA beta N) significantly improved the antibiotic activity in mostcases, with MIC values as low as 2.5 mu M and activity improvementfactors as high as 128-fold.}, language = {en} } @article{GeigerReitenbachHenscheletal.2021, author = {Geiger, Christina and Reitenbach, Julija and Henschel, Cristiane and Kreuzer, Lucas and Widmann, Tobias and Wang, Peixi and Mangiapia, Gaetano and Moulin, Jean-Fran{\c{c}}ois and Papadakis, Christine M. and Laschewsky, Andr{\´e} and M{\"u}ller-Buschbaum, Peter}, title = {Ternary nanoswitches realized with multiresponsive PMMA-b-PNIPMAM films in mixed water/acetone vapor atmospheres}, series = {Advanced engineering materials}, volume = {23}, journal = {Advanced engineering materials}, number = {11}, publisher = {Wiley-VCH}, address = {Weinheim}, issn = {1438-1656}, doi = {10.1002/adem.202100191}, pages = {12}, year = {2021}, abstract = {To systematically add functionality to nanoscale polymer switches, an understanding of their responsive behavior is crucial. Herein, solvent vapor stimuli are applied to thin films of a diblock copolymer consisting of a short poly(methyl methacrylate) (PMMA) block and a long poly(N-isopropylmethacrylamide) (PNIPMAM) block for realizing ternary nanoswitches. Three significantly distinct film states are successfully implemented by the combination of amphiphilicity and co-nonsolvency effect. The exposure of the thin films to nitrogen, pure water vapor, and mixed water/acetone (90 vol\%/10 vol\%) vapor switches the films from a dried to a hydrated (solvated and swollen) and a water/acetone-exchanged (solvated and contracted) equilibrium state. These three states have distinctly different film thicknesses and solvent contents, which act as switch positions "off," "on," and "standby." For understanding the switching process, time-of-flight neutron reflectometry (ToF-NR) and spectral reflectance (SR) studies of the swelling and dehydration process are complemented by information on the local solvation of functional groups probed with Fourier-transform infrared (FTIR) spectroscopy. An accelerated responsive behavior beyond a minimum hydration/solvation level is attributed to the fast build-up and depletion of the hydration shell of PNIPMAM, caused by its hydrophobic moieties promoting a cooperative hydration character.}, language = {en} } @article{MelaniNagataSaalfrank2021, author = {Melani, Giacomo and Nagata, Yuki and Saalfrank, Peter}, title = {Vibrational energy relaxation of interfacial OH on a water-covered alpha-Al2O3(0001) surface}, series = {Physical chemistry, chemical physics : PCCP ; a journal of European chemical societies}, volume = {23}, journal = {Physical chemistry, chemical physics : PCCP ; a journal of European chemical societies}, number = {13}, publisher = {Royal Society of Chemistry}, address = {Cambridge}, issn = {1463-9076}, doi = {10.1039/d0cp03777j}, pages = {7714 -- 7723}, year = {2021}, abstract = {Vibrational relaxation of adsorbates is a sensitive tool to probe energy transfer at gas/solid and liquid/solid interfaces. The most direct way to study relaxation dynamics uses time-resolved spectroscopy. Here we report on a non-equilibrium ab initio molecular dynamics (NE-AIMD) methodology to model vibrational relaxation of OH vibrations on a hydroxylated, water-covered alpha-Al2O3(0001) surface. In our NE-AIMD approach, after exciting selected O-H bonds their coupling to surface phonons and to the water adlayer is analyzed in detail, by following both the energy flow in time, as well as the time-evolution of Vibrational Density of States (VDOS) curves. The latter are obtained from Time-dependent Correlation Functions (TCFs) and serve as prototypical, generic representatives of time-resolved vibrational spectra. As most important results, (i) we find a few-picosecond lifetime of the excited modes and (ii) identify both hydrogen-bonded aluminols and water molecules in the adsorbed water layer as main dissipative channels, while the direct coupling to Al2O3 surface phonons is of minor importance on the timescales of interest. Our NE-AIMD/TCF methodology is powerful for complex adsorbate systems, in principle even reacting ones, and opens a way towards time-resolved vibrational spectroscopy.}, language = {en} } @article{WangFritschBerendtsetal.2021, author = {Wang, Zhenyu and Fritsch, Daniel and Berendts, Stefan and Lerch, Martin and Breternitz, Joachim and Schorr, Susan}, title = {Elucidation of the reaction mechanism for the synthesis of ZnGeN2 through Zn2GeO4 ammonolysis}, series = {Chemical science / RSC, Royal Society of Chemistry}, volume = {12}, journal = {Chemical science / RSC, Royal Society of Chemistry}, number = {24}, publisher = {Royal Society of Chemistry}, address = {Cambridge}, issn = {2041-6539}, doi = {10.1039/d1sc00328c}, pages = {8493 -- 8500}, year = {2021}, abstract = {Ternary II-IV-N-2 materials have been considered as a promising class of materials that combine photovoltaic performance with earth-abundance and low toxicity. When switching from binary III-V materials to ternary II-IV-N-2 materials, further structural complexity is added to the system that may influence its optoelectronic properties. Herein, we present a systematic study of the reaction of Zn2GeO4 with NH3 that produces zinc germanium oxide nitrides, and ultimately approach stoichiometric ZnGeN2, using a combination of chemical analyses, X-ray powder diffraction and DFT calculations. Elucidating the reaction mechanism as being dominated by Zn and O extrusion at the later reaction stages, we give an insight into studying structure-property relationships in this emerging class of materials.}, language = {en} } @article{SaeediGarakaniXieKhorsandKheirabadetal.2021, author = {Saeedi Garakani, Sadaf and Xie, Dongjiu and Khorsand Kheirabad, Atefeh and Lu, Yan and Yuan, Jiayin}, title = {Template-synthesis of a poly(ionic liquid)-derived Fe1-xS/nitrogen-doped porous carbon membrane and its electrode application in lithium-sulfur batteries}, series = {Materials advances}, volume = {2}, journal = {Materials advances}, number = {15}, publisher = {Royal Society of Chemistry}, address = {Cambridge}, issn = {2633-5409}, doi = {10.1039/d1ma00441g}, pages = {5203 -- 5212}, year = {2021}, abstract = {This study deals with the facile synthesis of Fe1-xS nanoparticle-containing nitrogen-doped porous carbon membranes (denoted as Fe1-xS/N-PCMs) via vacuum carbonization of hybrid porous poly(ionic liquid) (PIL) membranes, and their successful use as a sulfur host material to mitigate the shuttle effect in lithium-sulfur (Li-S) batteries. The hybrid porous PIL membranes as the sacrificial template were prepared via ionic crosslinking of a cationic PIL with base-neutralized 1,1 '-ferrocenedicarboxylic acid, so that the iron source was molecularly incorporated into the template. The carbonization process was investigated in detail at different temperatures, and the chemical and porous structures of the carbon products were comprehensively analyzed. The Fe1-xS/N-PCMs prepared at 900 degrees C have a multimodal pore size distribution with a satisfactorily high surface area and well-dispersed iron sulfide nanoparticles to physically and chemically confine the LiPSs. The sulfur/Fe1-xS/N-PCM composites were then tested as electrodes in Li-S batteries, showing much improved capacity, rate performance and cycle stability, in comparison to iron sulfide-free, nitrogen-doped porous carbon membranes.}, language = {en} } @article{XuNieWangetal.2021, author = {Xu, Xun and Nie, Yan and Wang, Weiwei and Ma, Nan and Lendlein, Andreas}, title = {Periodic thermomechanical modulation of toll-like receptor expression and distribution in mesenchymal stromal cells}, series = {MRS communications / a publication of the Materials Research Society}, volume = {11}, journal = {MRS communications / a publication of the Materials Research Society}, number = {4}, publisher = {Springer}, address = {Berlin}, issn = {2159-6859}, doi = {10.1557/s43579-021-00049-5}, pages = {425 -- 431}, year = {2021}, abstract = {Toll-like receptor (TLR) can trigger an immune response against virus including SARS-CoV-2. TLR expression/distribution is varying in mesenchymal stromal cells (MSCs) depending on their culture environments. Here, to explore the effect of periodic thermomechanical cues on TLRs, thermally controlled shape-memory polymer sheets with programmable actuation capacity were created. The proportion of MSCs expressing SARS-CoV-2-associated TLRs was increased upon stimulation. The TLR4/7 colocalization was promoted and retained in the endoplasmic reticula. The TLR redistribution was driven by myosin-mediated F-actin assembly. These results highlight the potential of boosting the immunity for combating COVID-19 via thermomechanical preconditioning of MSCs.}, language = {en} }