We report on an efficient assembly approach to a variety of electrostatically stabilized all-inorganic semiconductor nanocrystals (NCs) via their linking with appropriate ions into multibranched gel networks. These all-inorganic non-ordered 3D assemblies can combine strong interparticle coupling which facilitates charge transport between the NCs with their diverse morphology, composition, size, and functional capping ligands. Moreover, the resulting dry gels (aerogels) are highly porous monolithic structures, which preserve the quantum confinement of their building blocks. The inorganic semiconductor aerogel made of 4.5 nm CdSe colloidal NCs, capped with iodide ions and bridged with Cd2+ ions, exhibited a surface area as high as 146 m2/g.

Chemical synthesis of materials is facing enormous challenges at the present time. The necessary transition toward more sustainable economic processes requires new materials as well as optimized production of well-established materials. However, inorganic materials (e.g., ceramics or alloys) are typically produced industrially by high-temperature processes at up to 2000 °C. A relatively new approach for inorganic synthesis is based on so-called ionic liquids. Ionic liquids (ILs) — often defined as salts with melting points below 100 °C[1] — are usually composed of sterically demanding organic cations and (often) polyatomic anions, which can be selected in order to tune the properties of the IL. Owing to the distinctive physicochemical properties of ILs (e.g., wide liquidus range, high redox and thermal stability, (usually) negligible vapor pressure, tunable polarity), they have gained interest for a wide range of applications. Among the numerous inorganic materials accessible in ILs have been remarkable examples, especially in main-group element chemistry. For instance, a new metastable modification of germanium in the clathrate-II structure[2] or the largest known naked, main-group element cluster [Sn36Ge24Se132]24– (“Zeoball”).[3] The introduction of Lewis-acidic ILs has enhanced the convenience of polycation syntheses and enabled substitution of carcinogenic or toxic substances like benzene, SO2, or AsF5.[4] A considerable number of polycations of group 15 or 16 elements has been synthesized in ILs. The utilization of an IL as reaction medium can be decisive for the composition, structure, and physical properties of the (polycationic) reaction product.[5] In order to broaden the knowledge on synthesis techniques for inorganic materials near ambient temperature based on ILs, this thesis aimed at two goals: • Explorative synthesis of new inorganic compounds in ILs • Elucidating the influence of ILs on product formation For these two goals, metal-rich (polycationic) compounds of group 15 were chosen as promising chemical system, owing to the effectiveness of alkylimidazolium-based Lewis-acidic ILs for the synthesis of this class of compounds. A variety of new polycationic compounds has been successfully synthesized in Lewis-acidic ILs based on 1-n-butyl-3-methylimidazolium (or 1-ethy-3-methylimidazolium) halides and halogenido-aluminates. Determination of the crystal structures by single-crystal X-ray diffraction enabled analysis of their bonding situation supported by quantum-chemical calculations. In general, the employed ILs enabled syntheses with a high selectivity for the yielded polycation. Depending on the investigated chemical system, the following parameters were pinpointed to have significant influence: • Choice of starting materials • Choice of cation as well as anion of the IL • Reaction temperature • Concentration of starting materials in the IL The investigations were supported by NMR spectroscopy, which led to the discovery of nanoparticles of red phosphorus. This finding may stimulate the development of an easily accessible, reactive form of phosphorus without the hazardous drawbacks of the white allotrope. In addition, in situ NMR measurements in ILs were proven a viable option for mechanistic investigations. Conventional solid-state reaction as well as ionothermal syntheses yielded the new layered compounds M2Bi2S3(AlCl4)2 (M = Cu, Ag), which can be interpreted as Bi2S3 molecules embedded in MAlCl4 salts. The choice of starting materials was found to have a crucial influence on the crystallized polytype. Omitting the IL hindered the formation of crystals suitable for single-crystal structure determination. The three new main-group element heteropolycations [Bi6Te4Br2]4+, [Bi3S4AlCl]3+, and [Sb13Se16]7+ as well as known [Bi4Te4]4+ has been synthesized under ionothermal conditions. The Lewis-acidic ILs proved to be exceptional solvents for elements and their halides, and likewise for Bi2S3 and Bi2Te3. Hence, these solvents are not only advantageous reaction media for pnictogen and chalcogen chemistry but also potential (selective but expensive) ore-processing agents. These excellent solvent capabilities extend to complex ternary compounds including heavy transition metals such as Bi16PdCl22 and elemental platinum. This gave rise to the synthesis of metal-rich salts containing [Bi10]4+ antiprisms with an endohedral palladium or, for the first time, platinum atom. Furthermore, the filled bismuth polycation [Rh@Bi9]4+ or the complex cluster [Rh2Bi12]4+ could be obtained from dissolution and conversion of Bi12−xRhX13–x (X = Cl, Br) depending on the employed IL. Real-space bonding analysis revealed that [Rh2Bi12]4+ acquires a unique standing between dative bonding by bismuth polyions and mixed clusters following Wade-Mingos rules. References [1] J. S. Wilkes, P. Wasserscheid, T. Welton, in Ionic Liquids in Synthesis (Eds.: P. Wasserscheid, T. Welton), Wiley-VCH Verlag GmbH & Co. KGaA, 2007, pp. 1–6. [2] A. M. Guloy, R. Ramlau, Z. Tang, W. Schnelle, M. Baitinger, Y. Grin, Nature 2006, 443, 320–323. [3] Y. Lin, W. Massa, S. Dehnen, J. Am. Chem. Soc. 2012, 134, 4497–4500. [4] E. Ahmed, D. Köhler, M. Ruck, Z. Anorg. Allg. Chem. 2009, 635, 297–300. [5] E. Ahmed, J. Beck, J. Daniels, T. Doert, S. J. Eck, A. Heerwig, A. Isaeva, S. Lidin, M. Ruck, W. Schnelle, et al., Angew. Chem. 2012, 124, 8230–8233; Angew. Chem. Int. Ed. 2012, 51, 8106–8109.

Milch dient der Versorgung neugeborener Säugetiere mit allen lebensnotwendigen Nährstoffen, wie Proteinen, Fetten, Kohlenhydraten, Vitaminen und Mineralstoffen. Insbesondere die Proteingruppe der Caseine, die in der Milch zum Großteil zu Caseinmicellen assoziiert vorliegen, stellen essentielle Aminosäuren bereit und transportieren große Mengen Calcium und Phosphor (Fox, 2008; Horne, 2008). Neben der Bedeutung als erste Nahrungsquelle für Neugeborene haben sich Milch und Milchprodukte zu einem der wichtigsten Handels- und Verarbeitungsgüter entwickelt. In Deutschland ist vorrangig der Konsum von Kuhmilch verbreitet. Zunehmend wird aber auch die Milch von Büffel, Schaf und Ziege direkt oder verarbeitet konsumiert (Fox, 2008; Töpel, 2016). Dabei unterscheidet sich die Zusammensetzung der Milch zwischen den verschiedenen Tierarten zum Teil beträchtlich. Diese Unterschiede betreffen nicht nur die Anteile der Hauptnährstoffe, sondern auch die Eigenschaften und die Zusammensetzung der Caseinmicellen (CM) (Fox, 2008). Die Eigenschaften und die Stabilität gegenüber einer Calciumkomplexierung wurden für bovine Caseinmicellen in der Literatur bereits ausführlich diskutiert (Horne, 1984; Banon & Hardy, 1992; Needs et al., 2000; O’Connell et al., 2001; Huppertz et al., 2004). Über die Micellen anderer Tierarten lagen zu Beginn der Untersuchungen hingegen kaum Informationen vor. Ein Ziel der vorliegenden Arbeit war es deshalb, die Caseinmicellen aus der Milch der wiederkäuenden Paarhufer Kuh, Büffel, Schaf, Ziege und Kamel und der nicht wiederkäuenden Unpaarhufer Pferd und Esel sowie aus Humanmilch bezüglich Größe, Struktur, Zusammensetzung und Stabilität zu charakterisieren und daraus Erkenntnisse zum tierartspezifischen Micellaufbau abzuleiten. Hierzu wurden die Caseinmicellen mit Hilfe der Ultrazentrifugation von der Molke abgetrennt und in tierartspezifischem, synthetischem Milchultrafiltrate (SMUF) resuspendiert. Untersuchungen der hydrodynamischen Durchmesser mittels dynamischer Lichtstreuung zeigten, dass die CM der Nicht-Wiederkäuer Stute und Esel sowie des Kamels deutlich größer waren als die der Wiederkäuer Kuh, Büffel, Schaf und Ziege, wohingegen sich die humanen CM als die kleinsten zeigten. Mittels Rasterelektronenmikroskopie (REM) konnten aufgrund der beobachteten unterschiedlichen Oberflächenstrukturen für einige Tierarten Hinweise hinsichtlich einer größen- und κ-Casein-abhängigen Ausbildung von κ Casein ‚bunches‘ oder einer ‚hairy layer‘ an der Oberfläche der kolloidalen Partikel erhalten werden. Anhand der Aminosäurezusammensetzung der micellaren Proteine konnte abgeleitet werden, dass bei allen Tierarten vor allem Phosphoserin sowie die hydrophoben Aminosäuren maßgeblich am Aufbau der CM beteiligt sein dürften. Hierbei wurden jedoch tierartspezifische Unterschiede festgestellt. Bei den Wiederkäuern wurde eine besonders starke Assoziation der Caseinmonomere über Phosphoserincluster vermutet, während bei den Nicht-Wiederkäuern und insbesondere bei den humanen CM auch hydrophobe Wechselwirkungen eine entscheidende Rolle spielen. Calcium und anorganischer Phosphor konnten als die bedeutendsten micellaren Salze identifiziert werden, die in besonders hohen Gehalten in den CM von Stute und Esel vorkamen. Humane Micellen wiesen deutlich niedrigere Mineralstoffgehalte auf, weshalb die Bedeutung der elektrostatischen Wechselwirkungen für die Verknüpfung der Caseinmonomere geringer eingeschätzt wurde als bei den weiteren untersuchten Tierarten. In Bezug auf die Stabilität gegenüber einer Calciumkomplexierung mit Ethylenglycol-bis(2-aminoethylether)-N,N,N\',N\'-tetraessigsäure (EGTA) unterschieden sich die CM der Tiere sehr deutlich voneinander. Instabile Micellen zeichneten sich durch eine starke Abnahme der Trübung, eine Zunahme des extra-micellaren Caseins sowie eine schneller einsetzende Verkleinerung des hydrodynamischen Durchmessers aus. Für die Micellstabilität ergab sich die folgende Reihenfolge: Kuh << Büffel < Ziege < Schaf < Kamel = Stute < Esel < Mensch. Caseinmicellen eignen sich, neben dem natürlichen Transport von Aminosäuren und Mineralstoffen, als Nanotransporter für bioaktive Substanzen wie Vitamin D2 (Semo et al., 2007), β-Carotin (Sáiz-Abajo et al., 2013), Curcumin (Sahu et al., 2008), Triclosan (Roach et al., 2009) oder auch dem antibakteriellen Enzym Lysozym (de Roos et al., 1998; Anema & de Kruif, 2013). Da zu Beginn der Untersuchungen ausschließlich Daten zur Beladung boviner Caseinmicellen mit Hühnereiweißlysozym (HEWL) verfügbar waren, sollte zunächst die Stabilität der tierartspezifischen Micellen und die Effektivität der Beladung mit Lysozym beurteilt werden. Zusätzlich sollte die antibakterielle Wirksamkeit der mit Lysozym beladenen Caseinmicellen verschiedener Säugetiere sowohl in vitro als auch in orientierenden Untersuchungen gegenüber Bakterien erfasst werden. Dabei konnte gezeigt werden, dass die CM aller untersuchten Tierarten mit HEWL beladen werden können. Hinsichtlich der Stabilität der CM sowie der Aufnahmekapazität wurden jedoch tierartspezifische Unterschiede festgestellt. Allgemein konnten die CM aus Wiederkäuer- und aus Humanmilch als stabiler beschrieben werden, wobei die HEWL-Aufnahme bei den CM der Wiederkäuer höher war. Die lytische Enzymaktivität des HEWL in vitro veränderte sich infolge der Micellassoziation für die meisten untersuchten Tierarten im Vergleich zu frei vorliegendem HEWL nicht. Für die antibakterielle Wirksamkeit gegenüber Bacillus subtilis wurden hingegen Unterschiede zwischen den verschiedenen Tierarten beobachtet. Für die HEWL-haltigen CM von Büffel und Ziege ergaben sich die gleichen Wachstumsverzögerungen wie bei freiem HEWL in SMUF. Im Gegensatz dazu wurde die bakteriostatische Wirkung durch die HEWL-Micellen von Kuh, Kamel und Mensch inhibiert, durch die von Schaf, Stute und Esel hingegen verstärkt. Neben der Funktionalisierung der Caseinmicellen durch den Einbau bioaktiver Substanzen, können die Partikel auch chemisch modifiziert werden. Eine Möglichkeit stellt hierbei die Glykierung dar. Glykierungsreaktionen zwischen den Carbonylgruppen reduzierender Zucker und Aminosäureseitenketten wurden für nicht-micellare Caseine in einer Vielzahl an Studien untersucht (Zin El-Din & Aoki, 1993; Morales & van Boekel, 1996; Pellegrino et al., 1999; Lima et al., 2009; Akıllıoğlu & Gökmen, 2014). Über den Einfluss der micellaren Anordnung der Caseine auf die Glykierungsreaktionen war nur wenig bekannt. Erkenntnisse diesbezüglich könnten einen Beitrag zur Aufklärung des Aufbaus der Caseinmicellen leisten. Die Untersuchungen zeigten, dass bei der Erhitzung von micellaren und nicht-micellaren Caseinen für 0 - 4 h bei 100 °C in Gegenwart der reduzierenden Zucker Lactose und Glucose hauptsächlich die frühe Phase der Maillard Reaktion abläuft. Die Bildung der Amadori-Produkte erfolgte dabei in den CM und im nicht micellaren Natrium-Caseinat (NaCas) in gleichem Maße. Hieraus wurde eine ähnliche Zugänglichkeit der reaktiven Aminosäureseitenketten in den micellaren und nicht micellaren Caseinen geschlussfolgert. Signifikante Unterschiede konnten hinsichtlich der Produktbildung der späten Phase der Maillard-Reaktion beobachtet werden. Während Nε-Carboxymethyllysin (CML) im NaCas in höheren Gehalten detektiert wurde, trat in den CM eine verstärkte Pyrralin-Bildung auf. Zudem bewirkte eine Inkubation in Gegenwart von Lactose eine bevorzugte CML-Bildung, wohingegen mit Glucose Pyrralin in höheren Mengen gebildet wurde. Die Maillard-induzierten Proteinquervernetzungsprodukte Glyoxal-Lysin-Dimer und Pentosidin wurden im Vergleich zum zuckerunabhängig gebildeten Lysinoalanin in deutlich geringeren Gehalten erfasst. Hohe Oligomerisierungsgrade zwischen 50 und 84 % zeigten jedoch, dass die Proteinquer-vernetzungen, die im Zuge der Glykierung entstehen, quantitativ von größerer Bedeutung sind. Anhand der Bestimmung der hydrodynamischen Durchmesser und mit Hilfe von REM-Aufnahmen konnte eine weitgehend intra-micellare Proteinquervernetzung abgeleitet werden. Die Ausbildung intra-micellarer Oligomere bewirkte dabei eine höhere Micellstabilität gegenüber einem Calciumentzug durch EGTA. Die vorliegenden Untersuchungen deuten darauf hin, dass die hydrophilen Zuckermoleküle über die von Dalgleish (2011) vorgeschlagenen Wasserkanäle in die CM eindringen und die frühe Phase der Maillard-Reaktion anschließend vor allem in diesen Regionen erfolgt. Die weiteren Phasen der Maillard-Reaktion könnten dann, durch ein tieferes Eindringen der reaktiven Komponenten, zunehmend auch in dehydratisierteren Bereichen ablaufen. Bezüglich des Aufbaus der Caseinmicellen unterstützen die in dieser Arbeit gewonnen Ergebnisse die Vorstellungen des Internal Structure Modells.

This work aims towards the development of a modular system for fabrication of monodisperse microgels made of poly(2-oxazoline)s for use in the field of regenerative therapy.

Adsorption is a versatile purification technique to selectively separate different peptide fractions from a mixture using mild operation conditions. Porous carbons are ideally suited to separate ACE-inhibiting dipeptides by combining tailored size exclusion and polarity selectivity. The desired peptide fraction is mostly hydrophobic and very small and should adsorb inside hydrophobic micropores. The second topic of this thesis is linked to energy storage. The lithium-sulfur battery is a promising alternative to common lithium-ion batteries with theoretical capacities of up to 1672 mAh g−1 sulfur. The second aim of this thesis is to conduct an in-depth investigation of polysulfides interacting with selected carbon materials in a simplified battery electrolyte environment. The focus of this study is laid on the impact of surface polarity and pore size distribution of the carbon to develop a quantitative correlation between polysulfide retention and porosity metrics. Both, the enrichment of ACE-inhibitors and the retention of polysulfides rely on liquid phase adsorption in porous materials, linking the above mentioned topics. This thesis not only aims to develop an enrichment process or to find a superior battery cathode but also strives to explore structure-property relationships that are universally valid. Understanding the complex interplay of pore size and polarity leading to selective interactions between pore wall and the adsorbed species is given a high priority.

Bluthochdruck zählt zu einer der häufigsten Zivilisationskrankheiten und ist der Hauptfaktor für die Entstehung kardiovaskulärer Erkrankungen. Das Präventionspotenzial bei Hypertonie ist sehr hoch, da lebensstilassoziierte Faktoren wie Übergewicht, hoher Kochsalz- und Alkoholkonsum oder Stress die Entstehung eines erhöhten Blutdrucks wesentlich begünstigen. Daher wird eine antihypertensive Therapie meist mit nicht-medikamentösen Maßnahmen eingeleitet. Für die Regulation des Blutdrucks ist die nähere Betrachtung des Angiotensin-Converting Enzymes (ACE) wichtig, da es eines der Schlüsselenzyme des Renin-Angiotensin-Aldosteron-Systems und des Kallikrein-Kinin-Systems darstellt. Die Möglichkeit, dass ACE-inhibierende Peptide aus Lebensmittelproteinen über die Nahrungsmittelaufnahme einen positiven physiologischen Effekt auf den Blutdruck ausüben, ist ein vielversprechender Ansatz zur Unterstützung einer nicht-medikamentösen Therapie bei Hypertonie. In der Literatur sind zahlreiche Peptide beschrieben, welche eine inhibitorische Wirkung auf das ACE in vitro besitzen. Die vorliegende Arbeit beschäftigte sich mit der Klasse der tryptophanhaltigen Dipeptide, die in der Literatur als potente, natürliche ACE-Inhibitoren beschrieben sind. Die tryptophanhaltigen Peptide wurden hinsichtlich ihrer Gewinnung, ihrer Hemmwirkung auf das Zielenzym und bezüglich ihrer Bioverfügbarkeit in vitro und in vivo untersucht.

Die Funktionalisierung von tetra-PEG Makromolekülen mit fotoreaktiven Gruppen und die anschließende Umsetzung zu Hydrogelen durch fotochemische Vernetzung werden beschrieben. Die Funktionalisierung der Makromoleküle wird mittels UV-Vis- und NMR-Spektroskopie nachgewiesen, während der Verlauf der Vernetzung über die dynamische Lichtstreuung und IR-Spektroskopie betrachtet wird. Die hergestellten Hydrogele werden hinsichtlich des Sol-Anteils und der Quelleigenschaften untersucht. Über den Umsatz wird die Konzentration der Netzketten theoretisch berechnet. Einen weiteren Schwerpunkt bildet die Charakterisierung der Hydrogele hinsichtlich der mechanischen Eigenschaften. Über den Speichermodul wird die Konzentration der Netzketten experimentell bestimmt. Mittels dynamischer Lichtstreuung werden die kooperativen Diffusionskoeffizienten und Maschenweiten der Hydrogele bestimmt.

Yolk-shell nanostructures/yolk-shell nanoparticles are defined as a hybrid structure, a mixture of core/shell and hollow particles, where a core particle is encapsulated inside the hollow shell and may move freely inside the shell. Of the various classifications of yolk-shell nanostructures, a structure with an inorganic core and inorganic shell (inorganic/inorganic) has been studied widely due to their unique optical, magnetic, electrical, mechanical, and catalytic properties. In the work presented here, among the different inorganic/inorganic yolk-shell nanostructures noble metal@silica yolk-shell nanostructures has been chosen as the topic of interest. Silica shell possesses many advantages such as chemical inertness, tunable pore sizes, diverse surface morphologies, increasing suspension stability, no reduction in LSPR properties of noble metal nanoparticles when used as a coating for such particles. Noble metal nanoparticles such as AgNPs and AuNPs, on the other hand, possess unique structural, optical, catalytic, and quantum properties. Hence yolk-shell nanostructures with a combination of Ag or Au core and a silica shell (Ag@SiO2 and Au@SiO2) would open to endless possibilities. In this study, four areas were mainly explored: mechanism of silica shell formation over a given template, the synthetic modifications of Ag@SiO2 and Au@SiO2 yolk-shell nanostructures, their application as a potential catalyst, and devising of a flow type catalytic reactor. Despite the growing number of contributions on the topic of yolk-shell nanostructures, particularly Au@SiO2 and Ag@SiO2 yolk-shell nanostructures, a potential for improvement lies in all four aforementioned areas. As an initial study, the effect of different processing conditions as well as the mechanism of silica shell formation over reactive block copolymer templates was investigated. An asymmetric PS-b-P4VP block copolymer was chosen as a structure directing component to deposit silica shell. In order to deposit silica shell, PS-b-P4VP micelles with a collapsed PS core and a swollen P4VP corona was prepared via a solvent exchange method. The growth of silica shell over the PS-b-P4VP micelles (reactive template) was done using in-situ DLS and TEM. The experimental data obtained revealed the 4 distinct stages involved in the silica shell formation over the reactive BCP micellar template starting from the accumulation of silica precursor around the P4VP corona followed by a reactive template mediated hydrolysis-condensation reaction of the silica precursor which eventually lead to the shell densification and shell growth around the micelles. An understanding of the mechanism of silica shell formation over reactive templates provides a direct way to encapsulate various active species such as metal nanoparticles and quantum dots and paves the way for the template mediated synthesis of hybrid nanostructures such as yolk-shell nanoparticles. These studies also serve as a platform to fine-tune the properties of such hybrid nanostructures by varying the reaction parameters during silica shell deposition and reaction time. The next part of the work focused mainly on the synthesis, process optimisation and characterization of Ag@SiO2 and Au@SiO2 yolk-shell nanostructures, and their potential use as a nanocatalyst. A well-known soft template mediated synthesis of the yolk-shell nanostructure was adopted for the present work. For this PS-b-P4VP micelle was used as a dual template for both encapsulation of nanoparticle and the deposition of silica shell. The nanoparticles were entrapped selectively to the BCP micellar core and silica deposition was done by reacting the nanoparticle-loaded micelles with an acidic silica sol which lead to the formation of Ag@PS-b-P4VP@SiO2 or Au@PS-b-P4VP@SiO2 particles with respect to the nanoparticle used. In the case of Ag@PS-b-P4VP particles, upon silica deposition, a partial dissolution of AgNPs was observed whereas AuNPs were stable against dissolution. Hence yolk-shell nanostructures with AuNPs were studied further. As-prepared Au@PS-b-P4VP@SiO2 particles were then subjected to pyrolysis to remove the BCP template. The resulting yolk-shell nanostructures comprised of an AuNP core and a hollow mesoporous silica shell. Upon removal of the BCP template, the Au@SiO2 particles fused together and formed large aggregates. The catalytic properties of Au@SiO2 yolk-shell nanoparticles were explored using a model reaction of reduction of 4-nitrophenol and proved to have good catalytic activity and efficient recyclability. It was observed that catalytic efficiency was hindered by the particle aggregates formed after pyrolysis by creating an inhomogeneity in the system and inaccessibility of the catalytic surface for the reactants. Hence synthetic modifications were needed to overcome such drawbacks. Next part of the work deals with the synthetic modification of Au@SiO2 yolk-shell nanoparticles done by embedding them in a porous silica structure (PSS). Such structural morphology was attained by gelating the excess silica precursor while synthesising the Au@PS-b-P4VP@SiO2 particles. The pyrolytic removal of block copolymer results in the formation of Au@SiO2@PSS catalyst and the porous nature of both the shell and the silica structure provides an easy access for the reactants to the nanocatalyst surface located inside. The catalytic properties of Au@SiO2@PSS were studied using a model reaction of catalytic reduction of 4-nitrophenol (4-NP) and reductive degradation of different dyes. Kinetic studies show that Au@SiO2@PSS catalyst possesses enhanced catalytic activity as compared to other analogous systems reported in the literature so far. Furthermore, catalytic experiments on the reductive degradation of different dyes show that Au@SiO2@PSS catalyst can be considered as a very promising candidate for wastewater treatment. Another proposed direction of applying the Au@SiO2 yolk-shells is by devising a continuous flow catalytic system composed of Au@SiO2 yolk-shell nanoparticles for the effective degradation of azo dyes as a promising candidate for wastewater treatment. This was done by infiltrating the Au@PS-b-P4VP@SiO2 particles inside a porous glass substrate (frits) and the subsequent pyrolytic removal of the BCP template resulting in the formation of Au@SiO2 yolk-shell nanostructures sintered inside the frit pores. The flow catalytic reactor was exploited in terms of studying its catalytic activity in the degradation of azo dyes and 4-nitrophenol and proved to have a catalytic efficiency of ca. 99% in terms of reagent conversion and has a long-term stability under flow. Thus, with a few modifications, these flow type systems can open the doors to a very promising continuous flow catalytic reactor in the future.

To understand the mechanism of a pressure-induced structural phase transition, it is important to know which bonding changes lead to the stabilization of the new structure. A useful approach in this regard is the quantum chemical topology, which provides a large variety of indicators for the characterization of interatomic interactions. In this work, a number of topological indicators are used to analyze the bonding changes during the pressure-induced phase transition from the cubic diamond (cd) to the β-Sn-type structure of the elements of the 14th group of the periodic table. The ability of these indicators to reflect the presence of the cd → β-Sn transition in experiment for Si, Ge and Sn and its absence for carbon is investigated. Furthermore, the effect of pressure on the interatomic interactions in the cd- and β-Sn-type structures is examined. It is observed that the energy change along the cd → β-Sn transformation pathway correlates with the evolution of certain parameters of the electron density and the electron localizability indicator (ELI-D). Accordingly, criteria of structural stability were formulated based on characteristics of interatomic interactions. These results can serve as guidelines for the investigation of other solid-state phase transformations by the topological methods.

The contamination of foods with hydrocarbon mixtures migrating from food contact materials (FCM) was first observed for jute and sisal bags treated with batching oil in the 1990s. Since the millennium, the focus has shifted to printing inks and recycled cardboard packaging as most recognized sources for hydrocarbon contamination from FCM. Mineral oil containing printing inks can either release hydrocarbons directly from the printing of folding boxes into food or indirectly entering the recycling chain of cardboard material by printed products, such as newspapers. The contamination of dry foods with mineral oil hydrocarbons (MOH) from recycled fiber packaging has been reported to reach up to 100 mg/kg [1]. Using LC-GC-FID technique the MOH were categorized into mineral oil saturated hydrocarbons (MOSH) and mineral oil aromatic hydrocarbons (MOAH). The molecular mass, which is assumed to be toxicological relevant, is derived from the GC retention times of accumulated MOSH in human tissues and is limited to n C16 to n-C35 [2]. MOSH is the most significant contaminant of the human body reaching 1-10 g per person, which is of particular concern since a formation of microgranulomas (causing inflammatory reactions) in the liver was observed in rats fed with saturated hydrocarbons [3]. Furthermore, some MOAH are assumed to be genotoxic analogous to polycyclic aromatic hydrocarbons [3]. In the latest draft of a German ‘Mineral Oil Regulation’ the following limits for the migration of MOH from recycled fiber are proposed: for MOSH C16-20 4.0 mg/kg, MOSH C21-35 2.0 mg/kg and for MOAH 0.5 mg per kg food [4]. Functional barriers reducing the migration of undesirable compounds from recycled cardboards (such as MOH and other contaminants) could be a part of the solution for this issue. Supporting that approach in this study, the boxes of recycled cardboard featuring a barrier layer on the internal surface or an integrated adsorbent available early in 2014 were investigated for their efficiency in reducing migration of mineral oil hydrocarbons into dry food. A practice-oriented one-year storage test was performed with wheat flakes in seven configurations: a box of virgin fibers, two boxes of unprotected recycled cardboard, three cardboards with barrier layers (a flexo-printed polyacrylate layer, a polyvinyl alcohol coating and a multilayer involving polyester) and a cardboard containing activated carbon. The highest migration of MOH (C16-24) was observed in the boxes of unprotected recycled cardboard (MOSH: 11.4 mg/kg, MOAH: 2.4 mg/kg). Of the three investigated barrier layers only two reduced migration of MOH into food below the limits of the 3rd draft of the German mineral oil ordinance (2014) until the end of shelf life. The cardboard box involving active carbon as adsorbent prevented detectable migration of mineral oil hydrocarbons (<0.1 mg/kg). In the case of virgin fiber, which was virtually free of MOH (<1 mg/kg), migration close to the proposed limits was detected (C16-24, MOSH: 1.5 mg/kg, MOAH: 0.4 mg/kg). Therefore, it has been proven that the transport box (corrugated board) substantially contributed to the transfer of MOH into food. Plastic FCM can also release hydrocarbons, such as polyolefin oligomeric hydrocarbons (POH), into food. These POH are of synthetic nature and are formed during the polymerization process of polyolefins (150 – 3000 mg/kg in granulates of homo/hetero polymers involving ethylene and propylene). This group of synthetic contaminants contain also saturated hydrocarbons (POSH) analogous to mineral oils, but contrary no aromatic hydrocarbons. Further, a significant amount (10 – 50%) of monounsaturated hydrocarbons (POMH) was determined in the oligomeric fraction of polyolefins, which are not detectable in mineral oil products. Therefore, these POMH can be used as a marker for POH migration. A method based on two-dimensional high performance liquid chromatography on-line coupled to gas chromatography (on-line HPLC-HPLC-GC) was developed to enable the separate analysis of saturated, monounsaturated and aromatic hydrocarbons in extracts of packaging materials like polyolefins or paperboard and foods, repectively. It is an extension of the HPLC-GC method for MOSH and MOAH [1] using an additional argentation HPLC column, since normal-phase HPLC on silica gel did not preseparate saturated from monounsaturated hydrocarbons. Further, this method and comprehensive two-dimensional GC (GCxGC) was used to investigate the concentration of different oligomer types in polypropylene (PP) and polyethylene (PE) based sealing layers as well as their corresponding granulates. The analyzed sealing layers contained 180-995 mg/kg POSH and 90-435 mg/kg POMH (C16-35). Only in sealing layers involving low-density PE, oxidized polyolefin oligomers as well as cyclic oligomers (alkylated cyclopentanes and hexanes) have been detected. The transfer of POH (C16-35) from the investigated sealing layers into food can be substantial (>50%) and can reach more than 2 mg per kg food. The level of contamination depends on the oligomer content of the sealing layer, the fat content of the food, the processing temperature and the surface-volume ratio. Hot melt adhesives are widely utilized to glue cardboard boxes used as food packaging material. The analysed raw materials of hot melts mainly consisted of paraffinic waxes, hydrocarbon resins and polyolefins. The hydrocarbon resins, functioning as tackifiers, were the predominant source of hydrocarbons of sufficient volatility to migrate via gaseous phase into dry foods. The 18 hydrocarbon resins analyzed contained 8.2-118 g/kg saturated and up to 59 g/kg aromatic hydrocarbons (C16-24). These synthetic tackfier resins, especially the oligomers ≤C24, have been characterized structurally and migration into food was estimated using a food simulant and by the analysis of real food samples. About 0.5-1.5 % of the potentially migrating substances (C16 24) of a hot melt were found to be transferred into food under storage conditions, which can result in a food contamination of approximately 1 mg/kg food in this case. The order of magnitude depends on the absolute amount of potentially migrating substances from the hot melt, the hot melt surface, contact time, amount and type of foods.