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Today’s huge amount of data generation and transfer induced an urgent requirement for long-term data storage. Here, we demonstrate and discuss a novel concept for long-term storage using NV centers inside nanodiamonds. The approach is based upon the radiation-induced generation of additional vacancies (so-called GR1 states), which quench the initial NV centers, resulting in a reduced overall fluorescence lifetime of the NV center. Using the tailored fluorescence lifetime of the NV center to code the information we demonstrate a “beyond binary” data storage density per bit. We also demonstrate that this process is reversible by heating the sample or the spot of information. This proof of principle shows that our technique may be a promising alternative data storage technology, especially in terms of long-term storage due to the high stability of the involved color centers. In addition to the proof of principle demonstration using macroscopic samples, we suggest and discuss the usage of focused electron beams to write information in nanodiamond materials, to read it out with focused low-intensity light, and to erase it on a macro, micro, or nanoscale.

The islet amyloid polypeptide (IAPP) is a regulatory peptide that can aggregate into fibrillar structures associated with type 2 diabetes. In this study, the IAPP21-27 segment was modified with a biotin linker at the N-terminus (Btn-GNNFGAIL) to immobilize peptide fibrils on streptavidin-coated surfaces. Key residues for fibril formation of the N-terminal biotinylated IAPP21-27 segment were identified by using an alanine scanning approach combined with molecular dynamics simulations, thioflavin T fluorescence measurements, and scanning electron microscopy. Significant contributions of phenylalanine (F23), leucine (L27), and isoleucine (I26) for the fibrillation of the short peptide segment were identified. The fibril morphologies of the peptide variants differed depending on their primary sequence, ranging from flexible and semiflexible to stiff and crystal-like structures. These insights could advance the design of new functional hybrid bionanomaterials and fibril-engineered surface coatings using short peptide segments. To validate this concept, the biotinylated fibrils were immobilized on streptavidin-coated surfaces under spatial control.

Amorphous iron(III) oxide thin films have been prepared by vacuum ultraviolet (VUV) photochemically initiated oxidative conversion of [Fe(OtBu)3]2 at ambient temperature and pressure. The decomposition process and kinetics for conversion of [Fe(OtBu)3]2 precursor film thicknesses of 109–330 nm to much thinner and crack-free iron(III) oxide films (38–54 nm) were investigated. Due to the film shrinkage, higher densities as compared to hydrolysis (3.15 vs. 2.6 g cm−3) could be achieved. Mechanistic insight by DFT calculations and FTIR spectroscopy suggests the formation of intermediate Fe(CO2)-ring structures throughout the photochemical conversion process. Resulting iron(III) oxide layers were almost carbon free and exhibiting high transparency in the visible range. The proposed photochemical synthesis pathway represents an attractive route in achieving a dense metal oxide coating at low temperatures, e.g. for coating onto thermally sensitive substrates.

In the present article, electrodes containing a composite of platinum on top of a plasma-oxidized multi-layer graphene film are investigated as model electrodes that combine an exceptional high platinum utilization with high electrode stability. Graphene is thereby acting as a separator between the phosphate-based electrolyte and the platinum catalyst. Electrochemical impedance measurements in humidified hydrogen at 240 °C show area-normalized electrode resistance of 0.06 Ω·cm−2 for a platinum loading of ∼60 µgPt·cm−2, resulting in an outstanding mass normalized activity of almost 280 S·mgPt−1, exceeding even state-of-the-art electrodes. The presented platinum decorated graphene electrodes enable stable operation over 60 h with a non-optimized degradation rate of 0.15% h−1, whereas electrodes with a similar design but without the graphene as separator are prone to a very fast degradation. The presented results propose an efficient way to stabilize solid acid fuel cell electrodes and provide valuable insights about the degradation processes which are essential for further electrode optimization.

This work demonstrates the enhancement of the adsorption properties of polyethersulfone (PES) microfiltration membranes for 17&beta, estradiol (E2) from water. This compound represents a highly potent endocrine-disrupting chemical (EDC). The PES membranes were modified with a hydrophilic coating functionalized by amide groups. The modification was performed by the interfacial reaction between hexamethylenediamine (HMD) or piperazine (PIP) as the amine monomer and trimesoyl chloride (TMC) or adipoyl chloride (ADC) as the acid monomer on the surface of the membrane using electron beam irradiation. The modified membranes and the untreated PES membrane were characterized by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), water permeance measurements, water contact angle measurements, and adsorption experiments. Furthermore, the effects of simultaneous changes in four modification parameters: amine monomer types (HMD or PIP), acid monomer types (TMC or ADC), irradiation dosage (150 or 200 kGy), and the addition of toluene as a swelling agent, on the E2 adsorption capacity were investigated. The results showed that the adsorption capacities of modified PES membranes toward E2 are &gt, 60%, while the unmodified PES membrane had an adsorption capacity up to 30% for E2 under similar experimental conditions, i.e., an enhancement of a factor of 2. Next to the superior adsorption properties, the modified PES membranes maintain high water permeability and no pore blockage was observed. The highlighted results pave the way to develop efficient low-cost, stable, and high-performance adsorber membranes.

Interactions between ion beams and polymers have great potential to tailor the properties of the polymer surface by modifying the morphology as well as the chemical composition. The application of a wide range of ion incidence angles (0° - 75°) for the erosion of the commercially available photoresist AZ 4562® revealed a multitude of nanopatterns as investigations using atomic force microscopy and scanning electron microscopy have shown. A sequence of angle-dependent patterns (nanoholes, ripples, facets) can be observed, which are already known from inorganic materials. Additionally, the variation of the erosion time (5 min – 60 min) showed an evolution of the nanopatterns. A changed composition of the polymer surface could be detected by means of X-ray photoelectron spectroscopy.

Polymer membranes are powerful filtration tools in medicine and water treatment. Their efficiency and operational lifetime is limited by biofouling caused by microorganisms. This study describes the development of photodynamical active antimicrobial polymer membranes in a one-pot functionalization step using a well-known photosensitizer (PS). Commercially available polyethersulfone (PES) membranes for microfiltration were doped with the polycationic PS TMPyP using electron beam irradiation. These membranes were characterized in terms of binding stability and quantification of the PS and membrane morphology. Furthermore, the photodynamic ability was verified by time resolved singlet oxygen luminescence scans and successfully tested against the Gram-negative bacterium E. coli under low dose white light illumination resulting in the reduction in cell survival of 6 log10 units. Finally, in preliminarily experiments the photodynamic action against the Gram-positive bacteria M. luteus and the Gram-negative P. fluorescence and the mold C. cladosporioides was demonstrated. These promising results show the high photodynamic potential of electron beam functionalization of PES membranes with TMPyP. It preserves the photodynamic abilities of the immobilized PS resulting in efficient photodynamic inactivation of bacteria and mold on the membrane surface. The uprising worldwide spread of antibiotic resistant bacteria makes the development of new antibacterial strategies an inevitable challenge. The photodynamic inactivation of bacteria and its adaptation for antimicrobial surfaces, e.g. filtration membranes for water treatment, displays many advantages in terms of a wide application range, low mutagenic potential and environmental compatibility.

Immobilization of different digestive enzymes consisting of proteases, amylases and lipases on polyvinylidene fluoride resulted in biocatalytic active polymer membranes with self-cleaning capability. Activation of enzymes and therefore “switching on” the membrane system was achieved by adjusting pH and temperature leading to an active degradation of fouled substances on its surface. Fouling and self-cleaning experiments with solutions of protein, lipid, carbohydrate, and a mixture were performed and resulted in high recovery of water permeance (99%, 72%, 77%, and 68%, respectively). Furthermore, real samples including river water (75% after first cycle), and household sewage (62%) were examined, as well as first investigations in longtime performance, and stability were performed. Comprehensive membrane characterization was conducted by investigation of the immobilized enzyme concentration, enzyme activity, fouling tests and water permeation monitoring, mercury porosimetry, X-ray photoelectron spectroscopy, scanning electron microscopy, and finally, zeta potential, as well as water contact angle measurements.

The islet amyloid polypeptide (IAPP) is a regulatory peptide that can aggregate into fibrillar structures associated with type 2 diabetes. In this study, the IAPP

Surface functionality of nanodiamonds is of crucial importance for their desired chemical, optical and electromagnetic properties. Chlorinated surfaces are expected to enable an easy further modification of diamond surfaces via various substitution reactions for targeted molecule grafting, particularly interesting for biochemical applications. Previously reported chlorination approaches of diamonds required troublesome handling of hazardous chemicals, such as chlorine gas, and long chlorination time or high temperature. Here, we describe a radiation chemistry approach using electron beam irradiation for efficient surface chlorination of nanodiamonds (with averaged diameter of ca. 30 nm) at ambient temperature. Nanodiamonds with hydrogenated and graphitized surfaces were used for chlorination in CCl4, CHCl3 and CH2Cl2 at increasing radiation doses. A comprehensive set of measurements, including XPS, ATR-FTIR and in-source thermal desorption mass spectrometry (IS-TD-MS) was applied to characterize the chlorinated products. Density functional theory (DFT) calculations were performed to assist the discussion of reaction mechanisms. It is confirmed that remarkable covalently chlorine-covered surfaces bearing adequate stability against air and water were achieved for hydrogenated nanodiamonds in CCl4 by applying doses ≥500 kGy.

Water pollution has prejudicial effects on human health and ecosystems. An advanced membrane technology, which uses less energy for pollutants removal from water, is strongly desired for improving cost efficiency. This study demonstrates a high-flux enabled non-functionalized hexagonal boron nitride (h-BN) lamellar membrane, which retains pollutants through adsorption mediated filtration system–a phenomenon that is not yet studied. The membrane is found to be pH responsive, and acidic solution increases anionic methyl orange (MO) and direct red-80 (DR-80) dyes retention up to ≥90%. It also improves permeance fluxes by ~15 and 61-folds for MO and DR-80, respectively, as compared with the previous studies. Next, the membrane qualifies to be a good adsorbent for pollutants removal. The maximum adsorption capacities of this h-BN membrane for bisphenol A, MO and DR-80 are 125.7, 120.8, and 328.2 mg g−1, respectively. Furthermore, the anti-fouling performance of the membrane has been studied. The membrane exhibits normal fouling tendency, but could be recovered to 80% after washing. The membrane is very stable, and no swelling is observed even in extremely high acidic and basic conditions. The membrane could be regenerated with ethanol treatment and retained dye removal efficiency (around 90%) after four consecutive cycles test.

Silver nanoprisms (AgNPrs) have been coated with end-group functionalized thermo-responsive poly-(N-isopropylacrylamide) (PNIPAM) synthesized via reversible addition–fragmentation chain transfer (RAFT) polymerization. The effect of the density of the polymer coating on the plasmonic properties in the visible range of light are investigated for various local environmental conditions such as temperature, pH and chloride ion concentration employing UV/VIS spectroscopy, X-ray diffraction (XRD), and scanning electron microscopy (SEM). It has been found that contrary to uncoated AgNPrs, the polymer modified AgNPrs resist against degradation processes induced by chloride ions. Depending on the surface coverage of the AgNPrs with the polymer, the degradation process can be used to adjust the optical properties of the AgNPrs. The functionalized PNIPAM modified AgNPrs display a thermal responsive behaviour, which can be observed as a reversible shift of the plasmon peak upon heating and cooling above or below the lower critical solution or phase transition temperature of the polymer (LCST). The modified AgNPrs could be employed to sense Cl− in a concentration range promising for the diagnosis of cystic fibrosis. Based on the present results we also present a more general concept for the use of polymer decorated silver nanoprisms as improved sensors for the microenvironment of the particles making use of the local field enhancement, polymer coating, as well as switching of the plasmon response, which enables fine-tuning of plasmon resonances and ultimately dynamic sensing with coated triangular silver nanoprisms.

Nanostructure formation on bulk metals (silver, gold, copper and titanium) by femtosecond Ti-sapphire laser irradiation (775 nm, 150 fs) is studied aiming the production of low-reflectivity surfaces and the better understanding of the development process. The experiments were performed in nitrogen, air, oxygen and helium environments at atmospheric pressure. The samples were irradiated with fluences in the 0.1–2 J/cm2 range and an average pulse number of 100 falling over a given area. The reflectivity of the treated surfaces was determined by a microspectrometer in the 450–800 nm range and their morphology was studied by scanning electron microscopy. The gas ambience influenced the results via two effects: formation processes and the chemically-induced modifications of the nanostructures. In case of He the nanoparticle aggregates–otherwise generally present–are predominantly missing, which leads to a lower darkening efficiency. The presence of oxygen enhances the darkening effect for copper mostly at lower fluences, while causes a slow increase in reflectivity in the case of titanium (in case of pure oxygen) in the high fluence range. The surface morphology in case of nitrogen and air were quite similar probably due to their close molecular mass values.

Ge-Sb-Te alloys are promising materials for non-volatile memory applications. Alloying of the materials with various elements is considered as prospective approach to enhance material properties. This work reports on the preparation and characterization of pure Ge-Sb-Te-O (GSTO) and alloyed with La-Sr-Mn-O (LSMO) thin films. Thermal heating of amorphous thin films to different temperatures show distinct crystallization behavior. A general trend is the decrease in the size of GSTO crystallites and the suppression in the formation of stable trigonal GSTO phase with increasing content of LSMO. Microstructural studies by transmission electron microscopy show the formation of metastable GSTO nanocrystallites dispersed in the amorphous matrix. Analysis of local chemical bonding by X-ray spectroscopy reveal the presence of different oxides in the GSTO-LSMO composites. Moreover, the composites with a high LSMO content exhibit higher crystallization temperature and significant larger sheet resistance in amorphous and crystalline phase, while a memory device made of GSTO-LSMO alloy reveals bipolar switching and synaptic behavior. In addition, the amount of LSMO in GSTO-LSMO thin films influences their optical properties and band gap. Overall, the results of this work reveal the highly promising potential of GSTO-LSMO nanocomposites for data storage and reconfigurable photonic applications as well as neuro-inspired computing.

Thin layers of titanium(IV) ethoxide [Ti(OEt)4] as a metal–organic precursor were spin-coated onto silicon wafers under inert conditions and subsequently photochemically converted to thin titanium(IV) oxide (TiOx) films employing vacuum ultraviolet (VUV) radiation from a xenon excimer lamp. The photochemical conversion was performed below 35 °C and at ambient pressure in a nitrogen atmosphere with an optimized content of oxygen. Ti(OEt)4 decomposition and its kinetics were monitored and analyzed by gas chromatography and infrared spectroscopy. Precursor layers with a thickness between 270 and 1060 nm could be converted into much thinner TiOx films (40–165 nm). The decrease in thin film thickness was found to coincide with the removal of organic side chains and densification to a compact oxide network. For precursor layers with a thickness of up to 550 nm, VUV irradiation with a moderate radiant exposure (He) of 2.3 J cm–2 led to almost carbon-free amorphous layers with a composition close to stoichiometri...

This research is focused on investigation of coupled plasmonic/metal-semiconductor nanomaterials. A two-step laser-assisted method is demonstrated for formation of plasmonic Ag nanoparticles (NPs) distributed into porous metal–oxide semiconductors. The mosaic Ag-ZnO target is used for laser ablation and, subsequently, laser annealing of the deposited layer is applied. The plasmon resonance properties of the nanostructures produced are confirmed by optical transmission spectroscopy. The wurtzite structure of ZnO is formed with tilted c-axis orientation and, respectively, a mixed Raman mode appears at 580 cm−1. The oxygen pressure applied during a deposition process has impact on the morphology and thickness of the porous nanostructures, but not on the size and size distribution of AgNPs. The porous nanocomposites exhibited potential for SERS applications, most pronounced for the oxygen deficient sample, grown at lower oxygen pressure. The observed considerable SERS enhancement of R6G molecules on AgNP/ZnO can be attributed to the ZnO-to-molecule charge transfer contribution, enhanced by the additional electrons from the local surface plasmon resonance (LSPR) of AgNPs to the ZnO through the conduction band.

This study presents a new method focussing on electrostatic interactions during fouling of microfiltration membranes. Therefore, a new fouling test system was developed. To investigate the impact of surface charge on membrane fouling charged polystyrene beads were used. Also, the tested polyethersulfone membranes were modified with differently charged functional groups. Zeta potential measurements were conducted to describe the charged state of the membranes and particles. Fouling was investigated by filtration of the particle suspensions through the different membranes. It was found that oppositely charged surfaces of the membrane and particle lead to membrane fouling due to electrostatic attraction. Accordingly, no fouling occurred for the combination of evenly charged surfaces due to electrostatic repulsion. Additional experiments with a zwitterionic membrane surface revealed that fouling significantly depends on the pH value. Possessing an isoelectric point of pH 7 this membrane can exists in a positively charged, uncharged, or negatively charged state. Again, fouling occurred when electrostatic attraction was present while electrostatic repulsion resulted in antifouling. In the case of an uncharged surface fouling occurred in general due to the absence of electrostatic interactions. These new findings allowed us to establish a new standard fouling test that reveals the influence of electrostatic interactions in a fouling problem. To further demonstrate the advantages of this system standard protein fouling experiments were conducted and compared. It was found that different types of interactions and changes in the tertiary structure of proteins have to be considered. Thus, the gained results were difficult to interpret and false assumptions may occur. In contrast, electrostatic forces are sufficient to explain the fouling of polystyrene beads. The fouling test system presented by the authors is solely focused on electrostatic interactions and has, therefore, a clear advantage compared to the common protein test system.

The zeta potential of membrane surfaces and the resulting electrostatic interactions are determining factors of membrane fouling. This study investigates the influence of environmental parameters like pH value, salt concentration, or ion valence on the zeta potential of polymer membranes and the resulting fouling. To control electrostatic forces charged polystyrene beads were used as fouling reagents. Also, polyethersulfone and polyvinylidene fluoride membranes were modified to possess an either positive or negative surface charge. Afterwards, suspensions of beads were filtered through the membranes in different electrolytic environments. Fouling occurred when membrane and beads are oppositely charged. Bead adsorption was not observed when both surfaces are evenly charged. The latter was found to be influenced by electrolyte concentration. High salt concentrations or present bivalent ions reduced the electrostatic repulsion between evenly charged surfaces and led to membrane fouling. Low salt concentrations did not influence the electrostatic repulsion. Thus, critical salt concentrations were determined and used to identify the critical zeta potential. In addition, the fouling of a zwitterionic membrane surface was investigated regarding its pH dependence. A critical zeta potential that is associated with membrane fouling was identified. The critical zeta potentials are similar for both pH and salt concentration dependence.

A major goal of membrane science is the improvement of the membrane performance and the reduction of fouling effects, which occur during most aqueous filtration applications. Increasing the surface hydrophilicity can improve the membrane performance (in case of aqueous media) and decelerates membrane fouling. In this study, a PES microfiltration membrane (14,600 L m&minus, 2 h&minus, 1 bar&minus, 1) was hydrophilized using a hydrophilic surface coating based on amide functionalities, converting the hydrophobic membrane surface (water contact angle, WCA: ~90&deg, ) into an extremely hydrophilic one (WCA: ~30&deg, ). The amide layer was created by first immobilizing piperazine to the membrane surface via electron beam irradiation. Subsequently, a reaction with 1,3,5-benzenetricarbonyl trichloride (TMC) was applied to generate an amide structure. The presented approach resulted in a hydrophilic membrane surface, while maintaining permeance of the membrane without pore blocking. All membranes were investigated regarding their permeance, porosity, average pore size, morphology (SEM), chemical composition (XPS), and wettability. Soxhlet extraction was carried out to demonstrate the stability of the applied coating. The improvement of the modified membranes was demonstrated using dead-end filtration of algae solutions. After three fouling cycles, about 60% of the initial permeance remain for the modified membranes, while only ~25% remain for the reference.

In the present work, highly ordered titanium dioxide (TiO2) nanotube anodes were grown using a rapid anodization process. The photoelectrochemical performances of these electrodes strongly depend on the anodization conditions. Parameters such as electrolyte composition, anodization potential and anodization time are shown to affect the geometrical parameters of TiO2 nanotubes. The optimal anodization parameters are determined by photocurrent measurements, linear sweep voltammetry and electrochemical impedance spectroscopy. The thickness of the tube wall and its homogeneity is shown to strongly depend on the anodization potential, and the formation mechanism is discussed. This study permits the optimization of the photocurrent density and contributes to further improvement of the photoelectrochemical water-splitting performance of TiO2 nanotube photoelectrodes.

Noble metal catalysts possess outstanding catalytic behaviors in organic reactions, photocatalysis, electrocatalysis and many other applications. Peptide fibrils are used for the controllable nanostructuring of metal nanoparticles with specific sizes, shapes and high-surface area structures. The degradation of these fibrils with O2-plasma yields interconnected networks of nanoparticles, similar to metallic nanowires. Herein, platinum nanoparticles (Pt-NPs) were synthesized by reduction using VUV excimer radiation. The particle size was characterized by dynamic light scattering (DLS). Due to agglomeration, the metal nanoparticles were stabilized using poly(vinyl pyrrolidone) (PVP) and the same synthesis procedure. The influence of the polymer PVP molecular weight (Mwt), PVP concentration (Cp) and VUV irradiation time on platinum nanoparticle size was investigated. Small (2–3 nm) Pt-NPs are formed in the case of PVP with Mwt = 10 000 g mol−1. With increasing PVP Mwt, decreasing PVP concentration and shorter irradiation times, larger sized nanoparticles appear. The applicability of templated platinum nanoparticles, both the PVP-stabilized and non-stabilized Pt-NPs, immobilized via electrostatic interactions on the solid phase-synthesized aniline-GGAAKLVFF (AFP) peptide fibrils was investigated to serve as possible electrode material. The plasma treatment of the nanoparticle-fibril-assemblies was also studied as a novel technique. The Pt-NPs-AFP fibrils and the PVP-stabilized-Pt-NPs-AFP fibrils nanohybrids were employed to modify electrodes and then subjected to O2-plasma treatment. These O2-plasma treated/modified electrodes exhibited high electrocatalytic activities towards oxygen reduction in cyclic voltammetry measurements. Thus, the aforementioned nanocomposites hold great potential for polymer electrolyte fuel cells and other electrochemical applications in miniature devices and microfluidic chips.

Titanium dioxide (TiO2) is described as an established material to remove pollutants from water. However, TiO2 is still not applied on a large scale due to issues concerning, for example, the form of use or low photocatalytic activity. We present an easily upscalable method to synthesize high active TiO2 nanoparticles on a polyethersulfone microfiltration membrane to remove pollutants in a continuous way. For this purpose, titanium(IV) isopropoxide was mixed with water and hydrochloric acid and treated up to 210 &deg, C. After cooling, the membrane was simply dip-coated into the TiO2 nanoparticle dispersion. Standard characterization was undertaken (i.e., X-ray powder diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy, water permeance, contact angle). Degradation of carbamazepine and methylene blue was executed. By increasing synthesis temperature crystallinity and photocatalytic activity elevates. Both ultrasound modification of nanoparticles and membrane pre-modification with carboxyl groups led to fine distribution of nanoparticles. The ultrasound-treated nanoparticles gave the highest photocatalytic activity in degrading carbamazepine and showed no decrease in degradation after nine times of repetition. The TiO2 nanoparticles were strongly bound to the membrane. Photocatalytic TiO2 nanoparticles with high activity were synthesized. The innovative method enables a fast and easy nanoparticle production, which could enable the use in large-scale water cleaning.

A UV-assisted process allows full-faced or local deposition of silver domains on textiles made of natural as well as synthetic fibers, which act as nuclei for subsequent galvanic metallization. SEM and XPS analyses indicate that the process generates particulate depositions – particles, aggregates – of elementary silver. Masking the UV irradiation confines silver deposition strictly to the exposed areas thus allowing patterning. Adhesion of the deposited silver is high on the studied natural fiber cotton and polyamide fibers. Adhesion on smooth and chemically inert synthethic fibers such as, e.g., poly(ethylene terephthalate) or para- and meta-aramids could be enhanced by finishing with poly(vinylamine) thus providing complex-forming amino groups. Although the process does not deposit a closed, electrically conducting layer, all studied samples could be metallized by galvanization. The resulting metal coatings exhibit high conductivity and wash stability. Following a patterned silver deposition, the subsequent galvanic metallization produced conductive patterns of identical geometry thus opening an avenue towards printed circuits on textile fabrics.

Oligopeptides containing internal π-system units are shown to self-assemble in water near nanoparticles into fibrillar nanostructures. We have investigated the biopolymer hybrid monomer of the overall structure `peptide-π-system-peptide' with the sequence VDFAG – perylene diimide (PDI) – GAFDV in the presence of Ag-nanoparticles. Unique to these self-assembling monomers is the fact that the π-conjugated unit has been directly embedded within the peptide backbone by way of a special synthetic coupling. The symmetric peptide-based molecular design enforces intimate π-π communication within the aggregates after self-assembly, making these nano structures attractive for optical or electronic applications. The assembly process can in principle be followed by the change in optical spectra of the monomer and ordered monomer π-systems. Here we show that the Ag-nanoparticles act as seeds for the fibrillation, which makes the fibrils grow in a defined fashion and the supramolecular assembly can be followed via the optical spectrum of the plasmon resonances of the silver nanoparticles, which depend sensitively upon the local environment, making the optical plasmon resonance spectra a nice probe for the assembly process, as well as the interaction of monomers and fibrillar structures in contact with the nanoparticles. While it has been known that these systems may aggregate under certain conditions towards nano fibrils the new aspect here is the controlled and accelerated fibrillation near silver nanoparticles, which results in fibrils of 15–150 nm in diameter and up to 10 μm long, partially incorporating the seed nanoparticles. This approach provides a novel avenue to synthesize bioorganic-hybrid systems (in high yields) in contact with Ag metal nanoparticles and possibly enables us to control the location of growth for the materials in future applications.

Defined arrangements of individual molecules are covalenty connected (""printed"") onto SAM-functionalised gold substrates with nanometer resolution. Substrates were initially pre-functionlised by coating with 3,3'-dithiodipropionic acid (DTPA) to form a self-assembled monolayer (SAM), which was characterised by atomic force microscopy (AFM), contact angle goniometry, cyclic voltammetry and surface plasmon resonance (SPR) spectroscopy. Pre-defined ""ink"" patterns displayed on DNA origami-based single-use carriers (""stamp"") were covalently conjugated to the SAM using 1-ethyl-3-(3-dimethylamino-propyl)carbodiimide (EDC) and N-hydroxy-succinimide (NHS). These anchor points were used to create nanometer-precise single-molecule arrays, here with complementary DNA and streptavidin. Sequential steps of the printing process were evaluated by AFM and SPR spectroscopy. It was shown that 30% of the detected arrangements closely match the expected length distribution of designed patterns, whereas another 40% exhibit error within the range of only 1 streptavidin molecule. SPR results indicate that imposing a defined separation between molecular anchor points within the pattern through this printing process enhances the efficiency for association of specific binding partners for systems with high sterical hindrance. This study expands upon earlier findings where geometrical information was conserved by the application of DNA nanostructures, by establishing a generalisable strategy which is universally applicable to nearly any type of prefunctionalised substrate such as metals, plastics, silicates, ITO or 2D materials.

In this study we present results from immersion freezing experiments with size-segregated mineral dust particles. Besides two already existing data sets for Arizona Test Dust (ATD), and Fluka kaolinite, we show two new data sets for illite-NX, which consists mainly of illite, a clay mineral, and feldspar, a common crustal material. The experiments were carried out with the Leipzig Aerosol Cloud Interaction Simulator. After comparing the different dust samples, it became obvious that the freezing ability was positively correlated with the K-feldspar content. Furthermore, a comparison of the composition of the ATD, illite-NX, and feldspar samples suggests that within the K-feldspars, microcline is more ice nucleation active than orthoclase. A coating with sulfuric acid leads to a decrease in the ice nucleation ability of all mineral dusts, with the effect being more pronounced for the feldspar sample.

Natural attenuation maybe a cost-efficient option for bioremediation of contaminated sites but requires knowledge about the activity of degrading microbes under in situ conditions. In order to link microbial activity to the spatial distribution of contaminant degraders, we combined the recently improved in situ microcosm approach, so-called 'direct-push bacterial trap' (DP-BACTRAP), with nano-scale secondary ion mass spectrometry (NanoSIMS) analysis on samples from contaminated constructed wetlands. This approach is based on initially sterile microcosms amended with (13)C-labelled benzene as a source of carbon and energy for microorganisms. The microcosms were introduced directly in the constructed wetland, where they were colonised by indigenous microorganisms from the sediment. After incubation in the field, the samples were analysed by NanoSIMS, scanning electron microscopy (SEM) and fluorescence microscopy in order to visualise (13)C-labelled microbial biomass on undisturbed samples from the microcosms. With the approach developed, we successfully visualised benzene-degrading microbes on solid materials with high surface area by means of NanoSIMS. Moreover, we could demonstrate the feasibility of NanoSIMS analysis of unembedded porous media with a highly complex topography, which was frequently reasoned to not lead to sufficient results.

The aim of the work was to investigate mechanistic details of the preparation of graphene-like materials (GLM) via reduction of graphene oxide (GO) in aqueous dispersions by electron beam (EB) generated reducing free radicals.A 10 MeV linear accelerator was employed to irradiate aqueous GO dispersions at ambient temperatures. The kinetics of GO reduction was followed using UV-Vis spectroscopy. The resulting GLM were characterized by X-ray photoelectron spectroscopy (XPS), Transmission electron microscopy (TEM), Raman spectroscopy and conductivity measurements.The reduction of GO could be afforded with high efficiency within minutes at room temperature via the reaction of GO with reducing radicals generated by EB irradiation. The detailed investigation of the reduction mechanism allowed a selection of the best reducing free radicals in terms of both their efficiency and environmental impact of their precursors and final products.The EB-treatment of aqueous GO dispersions is a highly efficient, environmentally friendly, cost-effective and easily up-scalable method for the preparation of GLM. The efficiency of the new reduction approach is comparable with the best existing methods.

This study focuses on the development of novel biocompatible macroporous cryogels by electron-beam assisted free-radical crosslinking reaction of polymerizable dextran and hyaluronan derivatives. As a main advantage this straightforward approach provides highly pure materials of high porosity without using additional crosslinkers or initiators. The cryogels were characterized with regard to their morphology and their basic properties including thermal and mechanical characteristics, and swellability. It was found that the applied irradiation dose and the chemical composition strongly influence the material properties of the resulting cryogels. Preliminary cytotoxicity tests illustrate the excellent in vitro-cytocompatibility of the fabricated cryogels making them especially attractive as matrices in tissue regeneration procedures.

In this study the influence of polyethylene glycol pore forming agents and the monomer selection on the conversion, the morphology and swelling properties of electron-beam derived macroporous cryogels was investigated. The cryogels were synthesized at subzero temperatures from aqueous solutions by applying a pulsed electron beam of a high-energy linear accelerator. The macroporous structure is templated by the ice crystals and the morphology and swelling characteristics depend on the type of monomers used. Pore forming agents introduce smaller pores in the naturally non-porous cryogel walls. The porous structure and swelling properties can be tailored by the choice of the monomer. The systems were thoroughly analyzed by scanning electron microscopy, X-ray photoelectron spectroscopy, thermogravimetrical analysis and mercury intrusion porosimetry.