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Spectroscopic ellipsometry of interfacial phase transitions in fluid metallic systems: KxKCl1-x and Ga1-xBix [online]

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ISBN: 3937300082 Year: DOI: 10.5445/KSP/812004 Language: ENGLISH
Publisher: KIT Scientific Publishing
Subject: Chemistry (General)
Added to DOAB on : 2019-07-30 20:01:59

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The investigation of the interfacial phase transitions in fluid systems with short-range intermetallic interactions are of great interest. The phenomena were studied in two systems exhibiting a liquid-liquid miscibility gap: at the fluid/wall interface in fluid KxKCl1-x and at the fluid/vacuum interface of the Ga1 xBix alloys. To characterize the interfacial changes of the ultra thin films (composition, thickness and their evolution with time) the spectroscopic ellipsometry was performed over a wide spectral range. Whereas in the experiments on KxKCl1-x an existing ellipsometer could be used, a completely new UHV-apparatus including the in-situ phase modulation ellipsometer had to be developed for Ga1 xBix alloys. For the KxKCl1-x system new results on complete wetting at solid-liquid coexistence as well as in the homogenous liquid phase (prewetting) are presented. The spectra show the typical F center absorption which indicates that the film is a salt-rich phase. The thickness strongly increases approaching the monotectic from 30 to 440 nm, which is in agreement with the tetra point wetting scenario. For this interpretation a quantitative description of the excess Gibbs energy has been developed. For the Ga1 xBix system the results on complete wetting, surface freezing and oscillatory interfacial instabilities are presented. The high-precision spectra have been recorded approaching the liquid-liquid miscibility. These spectra have been modeled using a Ga-Bi effective medium approximation for the substrate covered by a film of liquid Bi. The measurements give evidence of tetra point wetting in the Ga-Bi system. First ellipsometric study of the surface freezing in Ga-Bi has been performed. Within the miscibility gap a very interesting effect of surface and bulk oscillatory instability was observed. The details of this process at present are not well understood, but a qualitative description is given.

Compact Stars in the QCD Phase Diagram

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ISBN: 9783039219582 / 9783039219599 Year: Pages: 273 DOI: 10.3390/books978-3-03921-959-9 Language: eng
Publisher: MDPI - Multidisciplinary Digital Publishing Institute
Subject: Mathematics --- Science (General)
Added to DOAB on : 2020-01-30 16:39:46
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The book edition of the Universe Special Issue “Compact Stars in the QCD Phase Diagram” is devoted to the overarching aspects shared between heavy-ion collisions and compact star astrophysics in investigating the hadron-to-quark matter phase transition in the equation of state of strongly interacting matter in different regions of the phase diagram of QCD. It comprises 22 review and research articles that, together, will serve as a useful guide in educating both young and senior scientists in this emerging field that represents an intersection of the communities of strongly interacting matter theory, heavy-ion collision physics and compact star astrophysics.

Keywords

heavy-ion collisions --- directed flow --- hydrodynamics --- deconfinement --- hybrid stars --- neutron stars --- equation of state --- ? meson condensation --- maximum mass --- ? resonances --- finite temperature --- finite density --- quark-gluon plasma --- finite size --- speed of sound --- neutron stars --- equation of state --- in-medium effects --- neutrino --- Quantum Chromodynamics --- dense matter --- vector interaction --- neutron stars --- equation of state --- QCD matter --- phase transition --- critical point --- modified excluded-volume mechanism --- dense matter --- equation of state --- stars: neutron --- pulsars: general, pulsars: PSR J0737 ? 3039A --- pulsars: PSR J1757 ? 1854 --- relativistic heavy-ion collisions --- monte carlo simulations --- transport theory --- strangeness --- neutron stars --- star oscillations --- hadron–quark continuity --- neutron stars --- QCD phase diagram --- neutron stars --- stellar magnetic field --- stellar structure --- stellar evolution --- neutron star --- equation of state --- phase transition --- quark matter --- pulsars --- quark stars --- general relativity --- Gravitational waves --- Gamma-ray bursts --- nuclear matter --- neutron stars --- quarks --- combustion --- neutron star --- QCD matter --- phase transition --- critical point --- neutron stars --- gravitational waves --- equation of state --- chiral symmetry --- axion QED --- quark-hole pairing --- cold-dense QCD --- magnetic DCDW --- quark matter --- hadronic matter --- quark deconfinement --- neutron star matter --- nuclear equation of state --- phase transition --- crystalline structure --- neutrino emissivities --- cluster virial expansion --- quark-hadron matter --- Mott dissociation --- Beth-Uhlenbeck equation of state --- heavy-ion collisions --- supernova explosions --- mass-twin stars --- nuclear symmetry energy --- heavy-ion collisions --- transport theory --- collective flow --- light cluster emission --- meson production --- quark-hadron phase transition --- pasta phases --- speed of sound --- hybrid compact stars --- mass-radius relation --- GW170817

Advancements in Gel Science—A Special Issue in Memory of Toyoichi Tanaka

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ISBN: 9783039213436 / 9783039213443 Year: Pages: 178 DOI: 10.3390/books978-3-03921-344-3 Language: eng
Publisher: MDPI - Multidisciplinary Digital Publishing Institute
Subject: Technology (General) --- Chemical Technology
Added to DOAB on : 2019-12-09 11:49:15
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A gel is a state of matter that consists of a three-dimensional cross-linked polymer network and a large amount of solvent. Because of their structural characteristics, gels play important roles in science and technology. The science of gels has attracted much attention since the discovery of the volume phase transition by Professor Toyoichi Tanala at MIT in 1978. MDPI planned to publish a Special Issue in Gels to celebrate the 40th anniversary of this discovery, which received submissions of 13 original papers and one review from various areas of science. We believe that readers will find this Special Issue informative as to the recent advancements of gel research and the broad background of gel science.

Keywords

gel --- thermoresponsive property --- monomer sequence --- co-crosslinking --- copolymerization --- acrylamide derivative --- swelling --- volume phase transition --- agarose gel --- compression --- solvent transport --- sucrose --- xylitol --- volume phase transition --- effects of electric charge --- swelling of thermosensitive gels --- sol-gel transition --- site-bond correlated-percolation model for polymer gelation --- gelation temperature --- cloud point temperature --- spinodal temperature --- spinodal decomposition --- janus particle --- anisotropic shape --- phase separation --- wetting --- micrometric confinement --- micropipette aspiration --- PVA gel --- gamma ray sterilization --- artificial hydrogel cartilage --- frictional property --- wear --- xerogel --- Brunauer-Emmett-Teller theory --- Barrett-Joyner-Halenda analysis --- temperature --- solids content --- drying --- solvent exchange --- microgel --- electrophoresis --- light scattering --- paint coating --- wrinkle --- swelling --- buckling --- Sephadex® (crosslinked dextran) --- crosslink density (density of crosslinks) --- ice grain --- ice crystallization during rewarming --- glassy water --- X-ray CT --- XRD --- poly(vinyl alcohol) --- chemical gel --- microcrystallite --- hydrogen bond --- swelling behavior --- hysteresis --- hydrogel --- friction --- fatigue --- wear --- fracture --- crack --- adhesion --- delamination --- poly (acryl amide) gel --- time domain reflectometry (TDR) of dielectric spectroscopy --- pulse field gradient spin echo method of nuclear magnetic resonance (PFG-NMR) --- scaling analysis --- fractal analysis --- heterogeneous gelation dynamics --- moving boundary picture --- phase transition dynamics --- kinetic coefficient --- blood coagulation --- n/a

Synthesis and Applications of New Spin Crossover Compounds

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ISBN: 9783039213610 / 9783039213627 Year: Pages: 254 DOI: 10.3390/books978-3-03921-362-7 Language: eng
Publisher: MDPI - Multidisciplinary Digital Publishing Institute
Subject: Science (General) --- Physics (General)
Added to DOAB on : 2019-12-09 11:49:15
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The crystal chemistry of spin crossover (SCO) behavior in coordination compounds can potentially be in association with smart materials—promising materials for applications as components of memory devices, displays, sensors and mechanical devices and, especially, actuators, such as artificial muscles. This Special Issue is devoted to various aspects of SCO and related research, comprising 18 interesting original papers on valuable and important SCO topics. Significant and fundamental scientific attention has been focused on the SCO phenomena in a wide research range of fields of fundamental chemical and physical and related sciences, containing the interdisciplinary regions of chemical and physical sciences related to the SCO phenomena. Coordination materials with bistable systems between the LS and the HS states are usually triggered by external stimuli, such as temperature, light, pressure, guest molecule inclusion, soft X-ray, and nuclear decay. Since the first Hofmann-like spin crossover (SCO) behavior in {Fe(py)2[Ni(CN)4]}n (py = pyridine) was demonstrated, this crystal chemistry motif has been frequently used to design Fe(II) SCO materials to enable determination of the correlations between structural features and magnetic properties.

Keywords

spin crossover --- spin transition --- cobalt(II) ion --- paramagnetic ligand --- aminoxyl --- switch --- mosaicity --- spin crossover --- X-ray diffraction --- fatigability --- single crystal --- phase transition --- structural disorder --- spin-crossover --- dinuclear triple helicate --- Fe(II) --- solvent effects --- metal dithiolene complexes --- [Au(dmit)2]?, [Au(dddt)2]? --- ion-pair crystals --- [Fe(III)(3-OMesal2-trien)]+ --- coordination complexes --- crystal structure --- magnetic properties --- magnetic susceptibility --- magnetization --- spin-crossover transition --- Fe(II) complex --- dipyridyl-N-alkylamine ligands --- high spin (HS) --- low spin (LS) --- spin cross-over (SCO) --- magnetic transition --- cobalt oxide --- spin polaron --- impurity effect --- spin-state crossover --- coordination polymer --- supramolecular isomerism --- spin crossover --- crystal engineering --- spin crossover --- X-ray absorption spectroscopy --- soft X-ray induced excited spin state trapping --- high spin --- spin-crossover --- LIESST effect --- hydrogen bonding --- ?-? interactions --- charge-transfer phase transition --- iron mixed-valence complex --- hetero metal complex --- dithiooxalato ligand --- substitution of 3d transition metal ion --- ferromagnetism --- dielectric response --- 57Fe Mössbauer spectroscopy --- Fe(III) coordination complexes --- hexadentate ligand --- Schiff base --- spin crossover --- UV-Vis spectroscopy --- SQUID --- EPR spectroscopy --- spin-crossover --- optical microscopy --- reaction diffusion --- spin crossover --- Fe(III) complex --- qsal ligand --- thermal hysteresis --- structure phase transition --- counter-anion --- solvate --- lattice energy --- optical conductivity spectrum --- spiral structure --- 1,2-bis(4-pyridyl)ethane --- supramolecular coordination polymer --- chiral propeller structure --- atropisomerism --- spin crossover --- iron(II) complexes --- C–H···? interactions --- magnetic properties --- thermochromism --- spin crossover --- linear pentadentate ligand --- iron(II) --- mononuclear --- 1,2,3-triazole --- crystal structure --- magnetic properties --- DFT calculation --- intermolecular interactions --- amorphous --- spin crossover --- Cu(II) complexes --- nitroxides --- phase transitions --- magnetostructural correlations --- iron (II), spin crossover --- X-ray diffraction --- coordination polymers --- n/a

Molecular Magnets

Authors: ---
ISBN: 9783038977100 Year: Pages: 166 DOI: 10.3390/books978-3-03897-711-7 Language: eng
Publisher: MDPI - Multidisciplinary Digital Publishing Institute
Subject: Science (General) --- Chemistry (General)
Added to DOAB on : 2019-03-21 14:08:22
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Molecular magnets show many properties not met in conventional metallic magnetic materials, i.e. low density, transparency to electromagnetic radiation, sensitivity to external stimuli such as light, pressure, temperature, chemical modification or magnetic/electric fields, and others. They can serve as “functional” materials in sensors of different types or be applied in high-density magnetic storage or nanoscale devices. Research into molecule-based materials became more intense at the end of the 20th century and is now an important branch of modern science. The articles in this Special Issue, written by physicists and chemists, reflect the current work on molecular magnets being carried out in several research centers. Theoretical papers in the issue concern the influence of spin anisotropy in the low dimensional lattice of the resulting type of magnet, as well as thermodynamics and magnetic excitations in spin trimers. The impact of external pressure on structural and magnetic properties and its underlying mechanisms is described using the example of Prussian blue analogue data. The other functionality discussed is the magnetocaloric effect, investigated in coordination polymers and high spin clusters. In this issue, new molecular magnets are presented: (i) ferromagnetic high-spin [Mn6] single-molecule magnets, (ii) solvatomagnetic compounds changing their structure and magnetism dependent on water content, and (iii) a family of purely organic magnetic materials. Finally, an advanced calorimetric study of anisotropy in magnetic molecular superconductors is reviewed.

Advances in Chitin/Chitosan Characterization and Applications

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ISBN: 9783038978022 9783038978039 Year: Pages: 414 DOI: 10.3390/books978-3-03897-803-9 Language: eng
Publisher: MDPI - Multidisciplinary Digital Publishing Institute
Subject: Science (General) --- Biology --- Biochemistry
Added to DOAB on : 2019-04-25 16:37:17
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Functional advanced biopolymers have received far less attention than renewable biomass (cellulose, rubber, etc.) used for energy production. Among the most advanced biopolymers known is chitosan. The term chitosan refers to a family of polysaccharides obtained by partial de-N-acetylation from chitin, one of the most abundant renewable resources in the biosphere. Chitosan has been firmly established as having unique material properties as well as biological activities. Either in its native form or as a chemical derivative, chitosan is amenable to being processed—typically under mild conditions—into soft materials such as hydrogels, colloidal nanoparticles, or nanofibers. Given its multiple biological properties, including biodegradability, antimicrobial effects, gene transfectability, and metal adsorption—to name but a few—chitosan is regarded as a widely versatile building block in various sectors (e.g., agriculture, food, cosmetics, pharmacy) and for various applications (medical devices, metal adsorption, catalysis, etc.). This Special Issue presents an updated account addressing some of the major applications, including also chemical and enzymatic modifications of oligos and polymers. A better understanding of the properties that underpin the use of chitin and chitosan in different fields is key for boosting their more extensive industrial utilization, as well as to aid regulatory agencies in establishing specifications, guidelines, and standards for the different types of products and applications.

Keywords

aerogels --- chitosan --- ionic liquids --- ionogels --- zinc–chitosan complexes --- characterization --- bio-sorbent --- phosphate --- adsorption --- mechanism --- thermodynamic --- chitosan --- hydrogel --- phase transition --- gelation mechanism --- chitosan --- defense responses --- fruits --- nanoparticles --- plant growth --- pesticides --- Boron --- chitosan --- iron(III) hydroxide --- neodymium --- sorption --- chitin --- chitosan --- chitosan derivative --- chitin derivative --- oral care --- skin care --- hear care --- marine resources --- over-the counter-drug --- polymer carrier --- chitin --- chitosan --- nanostructured biomaterial --- polymer --- self-masking nanosphere lithography --- cicada --- chitosan --- self-assembled --- polyelectrolyte complex --- nanoparticle --- drug delivery --- Citrobacter --- biosynthesis --- bioflocculant --- chitosan --- metabolic pathway --- PEO/chitosan blend --- swelling --- mechanical properties --- wet and dried states --- chitosan --- biological activity --- medical applications --- chitosan --- PCL --- strontium --- scaffolds --- craniofacial engineering --- chitin --- chitosan --- derivatization --- controlled functionalization --- click chemistry --- graft copolymer --- cyclodextrin --- dendrimer --- ionic liquids --- chitin deacetylases --- chitosan --- chitooligosaccharides --- carbohydrate esterases --- structure --- substrate specificity --- deacetylation pattern --- binary --- chitosan --- desorption --- iron --- lead --- mercury --- salt effects --- single --- sorption competition --- chitosan supported copper --- heterogeneous catalyst --- organosilicon compound --- easily recyclable --- chitosan --- papermaking --- wet-end --- coating --- wastewater --- ionic cross-linking --- eco-friendly formulations --- thermal transition sol-gel --- drug delivery systems --- MTDSC --- DSC --- gene delivery --- non-viral vectors --- chitosan structure --- pDNA --- siRNA --- TEOS --- methylene blue --- chitosan --- modelling --- cross-linking --- interpenetrating --- XRD --- FTIR

Smart and Functional Polymers

Authors: --- ---
ISBN: 9783039215904 / 9783039215911 Year: Pages: 306 DOI: 10.3390/books978-3-03921-591-1 Language: eng
Publisher: MDPI - Multidisciplinary Digital Publishing Institute
Subject: Science (General) --- Chemistry (General) --- Inorganic Chemistry
Added to DOAB on : 2019-12-09 11:49:16
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This book is based on the Special Issue of the journal Molecules on “Smart and Functional Polymers”. The collected research and review articles focus on the synthesis and characterization of advanced functional polymers, polymers with specific structures and performances, current improvements in advanced polymer-based materials for various applications, and the opportunities and challenges in the future. The topics cover the emerging synthesis and characterization technology of smart polymers, core?shell structure polymers, stimuli-responsive polymers, anhydrous electrorheological materials fabricated from conducting polymers, reversible polymerization systems, and biomedical polymers for drug delivery and disease theranostics. In summary, this book provides a comprehensive overview of the latest synthesis approaches, representative structures and performances, and various applications of smart and functional polymers. It will serve as a useful reference for all researchers and readers interested in polymer sciences and technologies.

Keywords

amphiphilicity --- phase change --- polyamino acids --- degradability --- fine-tuning --- pH responsive --- poly(methacrylamide)s --- phase transition --- catalyst --- CO2 --- heterogeneous catalysis --- molecular sieve --- polyether imidazole ionic liquid --- Vitamin E --- albumin --- core-shell nanoparticles --- paclitaxel --- multi-drug resistance --- breast cancer --- conducting polymer --- composite --- electrorheological --- smart fluid --- viscoelastic --- controlled polymerization --- reversible polymerization --- sustainable polymers --- pH responsive polymers --- nanomedicine --- tumor imaging --- drug delivery --- polymerization dispersion method --- polyaniline --- polyvinyl alcohol --- glutaraldehyde --- chemical activation --- Glycopolymer --- post-polymerization functionalization --- perfluoroaryl azides --- Staudinger reaction --- castor oil --- biomedical devices --- polyurethanes --- polycaprolactone-diol --- chitosan --- fluoropolymers --- melt-shear organization --- chemical resistance --- solvent responsiveness --- hydrophobicity --- core/shell particles --- emulsion polymerization --- particle processing --- ?-NaYF4 --- rare earth upconversion nanoparticles --- core–shell structure --- hydrogels --- applications --- targeted drug delivery --- drug release --- hydrophobic drug delivery --- clinical translation --- versatile platform --- administration routes --- diverse therapeutic areas --- hearing loss --- saffron --- endophytic exopolysaccharide --- gentamicin --- cochlear hair cell --- polymeric nanoparticles --- stimuli-sensitive polymers --- co-delivery systems --- synergistic effect --- nucleic acid delivery --- chemotherapy --- phenylboronic acid --- gel --- glucose sensitivity --- drug delivery --- diabetes therapy --- amphiphilic copolymer --- hydrolyzable polyurea --- micelle --- controlled drug delivery --- cancer chemotherapy --- polymerization or post-polymerization modification methods --- polymer-based supramolecular chemistry --- stimuli-responsive polymers --- shape memory polymers --- self-healing polymers --- polymers for industrial catalysis --- polymers for water or effluent treatment --- polymers for sensing, separation, and purification --- polymers for fabrication --- renewable polymer materials used for agriculture --- functional polymers used in food science --- polymers for information storage, electronics, and energy conversion --- functional polymers for diagnosis, imaging, drug delivery, and tissue engineering --- polymers with biological activity (e.g., antitumor, antidiabetic, and antimicrobial activity) --- polymer-based medical devices

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