Konstantinos Andrikopoulos

Foundation for Research and Technology - Hellas | forth · Institute of Chemical Engineering Sciences (ICE-HT)

Nanomaterials are integrated within consumer products to enhance specific properties of interest. Their release throughout the lifecycle of nano-enabled products raises concerns; specifically, mechanical strains can lead to the generation of fragmented materials containing nanomaterials. We investigated the potential release of single-walled carbon...

The impact of titanium dioxide (TiO2) on the physical properties of Poly(lactic acid) (PLA) is explored, along with the combined effect of Atomic Layer Deposition of zinc oxide (ZnO) on the nanocomposite films’ surface. PLA/TiO2 bionanocomposites are prepared via melt-extrusion and characterized in terms of their morphological, thermal and mechanic...

The modification of cotton fabrics with water-soluble cationic copolymers for salt-free dyeing applications with reactive dyes is explored in the present work. To this end, a family of bifunctional water-soluble cationic copolymers was designed through the chemical modification of poly(4-vinyl benzyl chloride), PVBC, with triethylamine, TEAM. These...

In this work, we present the structural, optical and photocatalytic properties of CdS semiconducting nanostruc-tures, doped with palladium-and cobalt-based species. XRD analysis, corroborated by Raman and XPS, demonstrated the growth of CdS crystallites in the hexagonal structure, whereas solvothermal conversion of neat precursor metal salts result...

Cotton cationization with low molecular weight or polymeric cationic modifiers allows the effective dyeing of cotton substrates with reactive dyes under salt-free and more environmentally friendly conditions. The current work focuses on the spectroscopic study of the intermolecular interactions, which dictate the physicochemical process associated...

In this work, we present the structural, optical and photocatalytic properties of CdS semiconducting nanostructures, doped with palladium‐ and cobalt‐based species. XRD analysis, corroborated by Raman and XPS, demonstrated the growth of CdS crystallites in the hexagonal structure, whereas solvothermal conversion of neat precursor metal salts result...

Though an important and chronic source of dyes released to the environment, the determination of the release of dyes that occurs during household or industrial washing is usually disregarded. The main scope of this study is to reveal the extent of dye release through washing, and to understand if the modification of cotton fabrics with cationic pol...

Wood and wood-based products are extensively used in the building sector due to their interesting combination of properties. Fire safety and fire spread, however, are of utmost concern for the protection of buildings. Therefore, in timber structures, wood must be treated with fire-retardant materials in order to improve its reaction to fire. This a...

The modification of cotton fabrics with water-soluble cationic copolymers for salt-free dyeing applications with reactive dyes is explored in the present work. To this end, a family of bifunctional water-soluble cationic copolymers was designed through the chemical modification of poly(4-vinyl benzyl triethylammonium chloride), PVBC, with triethyla...

In the current study, a mixed microbial culture (MMC) of poly-hydroxyalkanoate (PHA) producers was developed under nutrient stress and assessed as a biocatalyst for the production of high-yielding PHAs from fermented discarded fruit juices (DFJ). The structure of the MMC was analyzed periodically to determine its microbial dynamics, revealing that...

The global trend in restrictions on pollutant emissions requires the use of catalytic converters in the automotive industry. Noble metals belonging to the platinum group metals (PGMs, platinum, palladium, and rhodium) are currently used for autocatalysts. However, recent efforts focus on the development of new catalytic converters that combine high...

In the current study, we propose a simple hydrothermal pathway to synthesize nano-structured Mg(OH)2 after application of thermal decomposition followed by hydration of commercial minerals based on hydromagnesite and huntite. The synthesis of nano-materials is performed without the use of any catalyst. The effect of decomposition temperature on the...

The present work describes the synthesis of metal-doped CdS/MoS 2 heterojunctions, prepared by a two-step microwave-assisted solvothermal approach. The samples were characterized by X-ray diffraction spectroscopy (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), Raman analysis as well as diffuse reflectance spectros...

Although the spin-crossover (SCO) phenomenon is well documented, tuning the SCO behaviour remains a challenging task. This could be mainly attributed to the ‘delicate’ nature of the phenomenon; cooperativity expressed through differences in particle size and morphologies, and electrostatic interactions could significantly affect the process. The go...

In this study, a simple, fast, one-pot approach for the isolation of nanowires (NWs) in coordination chemistry is reported. Nanowires (NWs) of spin-crossover (SCO) materials are extremely rare. Here, an innovative and easy synthetic process was developed to prepare NWs of a switchable polymorph of the known complex trans-[Fe(NCS)2(abpt)2] using a w...

The current work reports on a systematic study related to the vibrational modes of the ester carbonyl group in drawn polyesters. We have observed and try to explain how the presence of aromatic units in the molecular structure substantially affects the respective elements of the Raman tensor in contrast to the dipole moment derivative vector which...

Abstract The purpose of the present study was to analyze normal and degenerated menisci with Raman methodology on thin sections of formalin fixed paraffin embedding tissues and to correlate the Raman findings with the grade of meniscus degeneration. Menisci (n = 27) were removed from human knee joints after total knee replacement or meniscectomy. F...

Among the various organic pollutants and industrial chemicals, 4‐nitrophenol has been one of the most monitored substances in aqueous environments, due to its enhanced solubility in such systems. This research reports for the first time the microwave‐assisted synthesis of CdS/carbon/MoSx hybrids and the subsequent utilization of such systems as pho...

Tissue engineered constructs have the potential to respond to the unmet medical need of treating deep osteochondral defects. However, current tissue engineering strategies struggle in the attempt to create patterned constructs with biologically distinct functionality. In this work, a developmentally-inspired modular approach is proposed, whereby di...

The production and use of the pigment extracted from the murex molluscs is discussed here in association with the purple textile dyeing industry in the Prehistoric Aegean. “True” purple has been identified in a number of archaeological finds dating from the early Late Bronze Age, found in old and recent excavations at three different but contempora...

Hybrid polymeric materials incorporating carbon nanostructures or inorganic constituents stand as a promising class of materials exhibiting distinct but also complementary features. Carbon nanotubes have been proposed as unique candidates for polymer reinforcement; however, sustained efforts are further needed in order to make full use of their pot...

The incorporation of spin crossover (SCO) properties into metal–organic frameworks (MOFs) has led to an appealing subclass of multifunctional MOFs. Because temperature is the most common way to manipulate the SCO phenomenon, the spin state of relevant complexes is conveniently monitored by variable‐temperature magnetic susceptibility (χMT) measurem...

BaTiO3 is one of the most widely used ceramic components in capacitor formulation due to its exceptional ferroelectric properties. The structural transition from the ferroelectric tetragonal to the paraelectric cubic phase has been studied in both nano-and micro-BaTiO3 particles. Several experimental techniques were employed for characterization pu...

Nanoscale two‐dimensional nanostructures have shown great potential as functional components in photocatalysis. Here, investigations on the synthesis of heterostructured hybrids, comprised of 0D CdS nanoparticles as semiconductor and 2D/2D graphene/MoSx as co‐catalyst, are reported. The approach involves a rapid microwave‐assisted reaction in autoc...

This study evaluated roughness parameters and phase transformation of monolithic zirconia ceramics after various mechanical and laser thermal treatments. Fully sintered monolithic zirconia cylinder specimens were divided to five groups, according to the applied surface treatment: CL: control, GB: grit-blasted with glass particles. AL50: grit-blaste...

The spin-crossover (SCO) polymorph B (complex 1) of the known compound [Fe II {N(CN) 2 } 2 (abpt) 2 ], where abpt is 4-amino-3,5-bis(pyridin-2-yl)-1,2,4-triazole, has been prepared in three different particle sizes averaging ∼300 (sample 1a), ∼80 (sample 1b), and ∼20 nm (sample 1c). Two independent octahedral molecules possessing Fe1 and Fe2 were f...

Surface Enhanced Raman Spectroscopy (SERS) belongs to the techniques of ultra-sensitive chemical analysis and involves both identification and quantification of molecular species. Despite the fact that theoretically derived enhancement factors imply that even single molecules may be identified, which in some cases has indeed been experimentally obs...

The current work attempts to provide a proof of concept for the achievement of semi-quantitative measurements by applying Surface Enhanced Raman Scattering (SERS) on thermally dewetted Au-films. In order to probe the anticipated advanced (device) material, Mitoxantrone (MTX) that exhibits strong SERS signal was utilized as a relevant prototype acti...

The conformations of polymer chains in poly(ethylene oxide)/silica nanoparticles, PEO/SiO2, nanohybrids have been investigated through a combined approach that involves molecular dynamics (MD) simulations and attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) measurements. Systems with different polymer molecular weight...

The conformation of polymer chains under confinement is investigated in intercalated polymer/layered silicate nanocomposites. Hydrophilic poly(ethylene oxide)/sodium montmorillonite, PEO/Na⁺-MMT, hybrids were prepared utilizing melt intercalation with compositions where the polymer chains are mostly within the ~1 nm galleries of the inorganic mater...

The current work focuses on Maxon, a modern biocompatible/bioabsorbable polymer, utilized in the fabrication of surgical sutures, and attempts to explore the limits of controlling the administration rate of a properly incorporated model drug, mitoxandrone dihydrochloride. The control is attempted by tailoring both the structural properties of the h...

We report on the effect of the degree of oxidation on the broadband non-linear optical response and magnetic behavior of graphene oxide, as well as on a route for obtaining reduced graphene oxide with enhanced optical properties without sacrificing the high dispersibility of the parent graphene oxide. As more sp 3 states evolved with the rise in ox...

We report on the effect of the degree of oxidation on the broadband non-linear optical response and magnetic behavior of graphene oxide, as well as on a route for obtaining reduced graphene oxide with enhanced optical properties without sacrificing the high dispersibility of the parent graphene oxide. As more sp3 states evolved with the rise in oxi...

Cadmium selenide has been deposited on nanoparticulate titania films by one-step dynamic electrodeposition in aqueous environment using cadmium sulfate and selenium oxide mixtures as precursors. The molar concentration of cadmium sulfate was always 100 times higher than SeO2. Amorphous CdSe films have been obtained and they were characterized by se...

Non planar 14-π aromatic subphthalocyanine has been introduced for the first time as hole transporting material for organometal halide perovskite solar cells and achieved a power conversion efficiency of 6.6%. Cells stored in the dark under ambient conditions underwent an incubation period of nine days during which, we observed an increase in effic...

Solid state solar cells of inverted structure were constructed by successive deposition of nanoparticulate titania, antimony sulfide sensitizer and P3HT on FTO electrodes with PEDOT:PSS:Ag as counter electrode. Sensitized photoanode electrodes were characterized by XRD, Raman, XPS, FESEM and UV-vis. Small laboratory scale cells were first construct...

In the present work, the incorporation of multiwalled carbon nanotubes (MWCNTs) in isotactic polypropylene (i-PP) was examined in terms of water vapor transport. The structure of the composites, as well as the MWCNT dispersion, was characterized by scanning electron microscopy, Raman spectroscopy, thermal analysis, and X-ray diffraction. Furthermor...

In the present study, the influence of the thermal reduction on the water vapor transmission properties of thin graphene oxide (GO) membranes is evaluated. The macroscopically measured property of the Water Vapor Transmission Rate (WVTR) exhibits step like dependence contrary to the gradual microscopic structural alterations identified by several t...

Objectives: Dental zirconia restorations should present long-term clinical survival and be in service within the oral environment for many years. However, low temperature degradation could affect their mechanical properties and survival. The aim of this study was to investigate the effect of in vitro aging on the flexural strength of yttrium-stabi...

In the present work, the incorporation of multiwalled carbon nanotubes (MWCNTs) in isotactic polypropylene (i-PP) was examined in terms of water vapour transport. The structure of the composites, as well as the MWCNTs dispersion, was characterized by scanning electron microscopy, Raman spectroscopy, thermal analysis and X-ray diffraction. The compo...

Solid-state quantum dot sensitized solar cells based on nanocrystalline titania and poly(3-hexylthiophene) demonstrated an improved conversion efficiency by a combination of ZnSe and CdSe quantum dot sensitizers. Thus, a combination of 30% ZnSe-70%CdSe gave higher efficiency than CdSe or ZnSe alone. This result is justified by the combination of en...

We report a detailed investigation of vibrational modes, structure, and dynamics of elemental sulfur in the glassy and the supercooled state, using Raman scattering and ab initio calculations. Polarized Raman spectra are recorded - for sulfur quenched from 473 K - over a broad temperature range from 93 K to 273 K where the supercooled liquid crysta...

We report a high pressure Raman study of orthorhombic elemental sulfur from ambient pressure to ∼ 25 GPa. Using a near infrared laser and low laser intensity on the scattering volume, we achieve off-resonant conditions up to larger pressures in comparison with previous studies. Raman spectra were recorded over the full spectral range including exte...

We report on a detailed study of the photostructural changes in bulk glassy As2S3 under vacuum using Raman scattering. Various excitation energies were employed to achieve resonance and off-resonance conditions. Temperature-induced structural changes were also investigated at conditions far from resonance, in order to clarify the role of bandgap li...

The polymer chain conformation under confinement and the polymer morphology are investigated in hydrophilic PEO/Na^+-montmorilonite nanohybrids synthesized by melt and/or solution intercalation. Intercalated hybrids with mono- and bi-layers of PEO chains are obtained for all compositions covering the complete range from pure polymer to pure clay. F...

We present a detailed investigation of the vibrational dynamics of glassy sulfur (g-S). The large frequency range spanned in this study has allowed us to carefully scrutinize the elastic properties of g-S and to analyze their relation to various features of both the glassy and the liquid state. In particular, the acoustic properties of g-S present...

The polymer chain conformation under confinement and the morphology of the nanohybrid materials are investigated in hydrophilic polymer/layered silicate nanocomposites. A series of poly(ethylene oxide)/sodium montmorillonite hybrids were synthesized utilizing melt intercalation with compositions covering the complete range from pure polymer to pure...

Nanoindentation is used to study the mechanical properties at the nanoscale of the ternary Agx(As0.33S0.67)100−x glassy system for 0 ≤ x ≤ 25. Direct evidence for phase separation of a Ag-poor and a Ag-rich phase in the composition range 2 ≤ x ≤ 20 is provided. The volume of the Ag-rich phase increases with x and percolates at x ≈ 7. The mechanical...

Modifications in the living polymerization or λ-transition of liquid sulfur, caused by confinement in nanonoporous sol–gel-derived glasses, are investigated by Raman scattering. Raman spectra are analyzed to provide the extent of polymerization, through which the temperature-dependence of the respective heat capacity is calculated. The data reveal...

For the case example of GeTe, we demonstrate that the use of techniques that probe the average structure may lead to misleading conclusions regarding the nature of phase change. GeTe is a narrow band-gap semiconductor and a ferroelectric with the simplest conceivable structure that—according to previous studies—undergoes a ferroelectric-to-paraelec...

We present here a study of the acoustic dynamics of polymeric glassy sulfur. The data have been collected in the GHz frequency range by means of Brillouin light scattering for different scattering geometries. The choice of the experimental setup allows us to obtain information on the refractive index, n, that comes out to be close to that correspon...

This study examines the materials of a contemporary pictorial artwork, belonging to the Macedonian Museum of Contemporary Art in Thessaloniki (Greece), and needing conservation. The combined use of micro-FTIR and micro-Raman spectroscopy allowed the identification of almost all painting materials. Moreover, the stability of a series of synthetic pi...

Silver-doped As33S>67 and As33S33Se33 bulk glasses studied by means of Scanning Electron Microscopy (SEM) and infrared reflectivity, exhibit two-phase glasses, for a wide range of Ag concentration. Using the Effective Medium Approximation we show that the structure is actually a proper average of two components, a Ag-poor and a Ag-rich glass phase....

We report an in situ high pressure investigation of the structural change in vitreous As(2)S(3) up to 60 GPa using the diamond anvil cell and energy dispersive x-ray absorption spectroscopy. The main finding of the present study is a gradual elongation of the average As-S bond length, which takes place in the pressure range of 15-50 GPa. This chang...

Summary The current work refers to the pressure induced structural rearrangements of a model chalcogenide glass, As2S3. High pressure Raman experiments performed on a thermally annealed sample provide evidence of modifications in the short and medium range order. In order to avoid photo-induced structural rearrangements, off-resonance Raman spectra...

Stability of the linear orthorhombic polymer of C60 under pressure and laser irradiation is studied by Raman scattering and X-ray diffraction measurements. The Raman spectrum at ambient pressure remains unchanged, in the time scale of the experiment, up to an intensity of 3200 W/cm2 of the 514.5 nm line of an Ar+ laser, but irreversible changes are...

The old katholikon of St Stephen's monastery at the Meteora (site of the most important complex of monasteries in Greece after Mount Athos) is decorated with wall paintings that date from the beginning of 17th century. In terms of style, the artistic ensemble is altogether characteristic of the period. The painting technique has been examined by me...

The structure and dynamics of PEO/Na^+MMT nanocomposites is investigated by XRD, DSC, Raman spectroscopy, and quasi-elastic neutron scattering (QENS). For concentrations up to 20 wt% PEO, the PEO chains within the galleries form either a single- or a double-layer structure of intercalated chains; at higher PEO content only double-layers of intercal...

Two different data-fusion strategies are evaluated for the combination of the outputs of combined Raman/X-Ray fluorescence instrument. The studied application deals with the classification of ochre pigments investigated in the field of cultural heritage. The two fusion strategies are: (1) first level fusion: combines raw signals obtained from each...

The purpose of this study is to clarify important details about a Cumaean Sibyl painting that is preserved in a private collection. This work, bearing neither signature nor date, has never undergone conservation. It was executed after Domenichino's Cumaean Sibyl, a work known to have been used as a model by many 18th century painters. Investigation...

What the discerning gaze of the art historian has deduced from comparisons in style – namely, that the unsigned Baptism of Christ (dated 1567) comes from the hand of the master Cretan painter, El Greco – is now investigated by the dispassionate eye of technology. The examination by means of analytical methods of diagnosis aimed at making an in-dept...

The pressure response of the second-order Raman G′ band of bundled double- (DWCNTs) and single-wall carbon nanotubes (SWCNTs) has been investigated by means of Raman spectroscopy using the 632.8 nm excitation. The different pressure responses of the G′ peak in SWCNTs and its corresponding components associated with the inner and the outer tubes in...

Developing a novel experimental technique, we applied photon correlation spectroscopy using infrared radiation in liquid sulfur around T(lambda), i.e., in the temperature range where an abrupt increase in viscosity by 4 orders of magnitude is observed upon heating within few degrees. This allowed us - overcoming photoinduced and absorption effects...

Vibrational spectroscopy is applied on samples obtained from the excavation area of the medieval Monastery (10th century) of Karaach-Teke in Bulgaria. The results of the corresponding study, reveal the type of materials used for the creation of the wall-paintings and give evidence of Byzantine influence, a fact that further supports the well known...

Structural details of the amorphous binary GeTe and ternary Ge2Sb2Te5 (GST) phase-change materials are investigated with the aid of Raman scattering. In the case of the a-GeTe, a plethora of Raman bands have been recorded and assigned on the basis of a network structure consisting of corner- and edge-sharing tetrahedra of the type GeTe4−nGen (n=0,...

A large number of Byzantine illustrated manuscripts—precious monuments of the world’s cultural heritage—are preserved in numerous museums and monasteries around the globe. Hitherto no systematic study employing diagnostic methods has been undertaken either to identify their materials or to reveal the particularities of their painting technique, let...

The frequency-reduced representation, g(omega)/omega(2). of the vibrational density of states g(a)), known as the Boson peak is frequency used to extract information Oil structural and dynamical properties of glasses and supercooled liquids. The g(omega)/omega(2) representation is preferred over the true excess of the vibrational modes, defined as...

Single-wall carbon nanotubes (SWNT) hydrogenated at P≈5.0GPa and T≈500°C (SWNT-H) were investigated by micro-Raman spectroscopy. The main feature of the Raman spectrum of the as-prepared SWNT-H is a giant structureless hot luminescence background that screens all vibrational modes. This disorder-induced background, attributed to random binding of t...

In this work, individual single-wall carbon nanotubes (i-SWCNTs) and their parent bundled material (b-SWCNTs) are investigated by means of high pressure Raman spectroscopy. Pressure application results in the broadening and intensity redistribution of the radial breathing modes (RBMs) in both materials. These changes are more pronounced in the case...

The high pressure response of the second-order Raman G ′ band in a high quality bundled double wall carbon nanotube (DWCNT) material has been investigated by means of Raman spectroscopy up to 10 GPa. At ambient conditions two peaks appear, assigned to the inner and outer tubes of DWCNTs. Upon pressure application, the Raman signal of the outer tube...

Pressure effects on the vibrational modes of As2O3 glass have been investigated with the aid of Raman scattering. Emphasis was put on both the intramolecular vibrational modes at high energies as well as the low-energy excitations (Boson peak) of the glass. The pressure dependence of the spectral features of Raman bands was found to be significantl...

A new mobile instrumentation that takes advantage of the simultaneous utilisation of two micro-analytical techniques (Raman and XRF) has already been effected within the PRAXIS European project (Competitive and Sustainable growth programme, PRAXIS: A portable Raman–X-Ray instrument. No G6RD-CT-2001-00602). The instrument permits structural characte...

The photopolymerization of the orthorhombic C60 polymer has been studied by Raman spectroscopy as a function of laser intensity at ambient and high pressure conditions. The Raman spectra at ambient pressure, excited by 514.5nm, show irreversible changes at intensity ∼3200W/cm2, while at high pressure the transformation rate increases and the requir...

It was presented that polymer fraction of liquid sulfur continues to increase even at temperatures up to 731 K. It was observed that the calculated increase in the polymer fraction within the referred high temperature range is only 9% of the polymer fraction calculated at 573 K. Comparison with corresponding data provided by the Q-D method revealed...

A detailed pressure dependence study of the low energy excitations of glassy As2S3 is reported over a wide pressure range, up to 10 GPa. The spectral features of Boson peak are analyzed as a function of pressure. Pressure effects on the Boson peak are manifested as an appreciable shift of its frequency to higher values, a suppression of its intensi...

We report on an inelastic (Raman) light scattering study of the local structure of amorphous GeTe films. A detailed analysis of the temperature-reduced Raman spectra has shown that appreciable structural changes occur as a function of temperature. These changes involve modifications of atomic arrangements such as to facilitate the rapid amorphous-t...

Implications of reduction procedures applied to the low energy part of the vibrational density of states in glasses and supercooled liquids are considered by advancing a detailed comparison between the excess – over the Debye limit – vibrational density of states g(ω) and the frequency-reduced representation g(ω)/ω2 usually referred to as the Boson...

The role of “impurities” or doping on the living polymerization of sulfur has been put under focus by means of a temperature dependent Raman study of the AsxS100−x and SeyS100−y (x=0.5,2,5 and y=2,5) systems. Reduced isotropic Raman spectra have been analyzed properly to yield the temperature dependence of the extent of polymerization, ϕ(T), in eac...

Present-day multimedia strongly relies on re-writable phase-change optical memories. We find that, different from current consensus Ge2Sb2Te5 (GST), the material of choice in digital versatile discs---random access memory (DVD-RAM), possesses a structure similar to ferroelectric GeTe, namely that Ge and Sb atoms are located off-center giving rise t...

By means of x-ray absorption fine structure and Raman scattering spectroscopies we demonstrate that the structure of amorphous GeTe is likely to be a mixture of 4(Ge):2(Te) and 3(Ge):3(Te)-coordinated structural units. Upon crystallization, a rhombohedral (distorted rocksalt) structure is established with about 10% of vacancies occurring on Ge site...

The central idea of the preceding Comment [J. Chem. Phys. xxx, xxx (2004)] is tackled from different viewpoints and arguments are presented showing its invalidity. First, we show that the presence of non-S8 rings is negligible under the conditions in which our experiment was performed. Then we prove that, even if we consider the non-S8 ring’s prese...

The pressure response of double-wall carbon nanotubes has been investigated by means of Raman spectroscopy up to 10 GPa. The intensity of the radial breathing modes of the outer tubes decreases rapidly but remain observable up to 9 GPa, exhibiting a behavior similar (but less pronounced) to that of single-wall carbon nanotubes, which undergo a shap...

We report on a detailed, temperature-dependent, off-resonant Raman scattering study of glassy and supercooled selenium. Raman spectra in the frequency regime of the first-order scattering (5-450 cm(-1)) have been recorded over a wide temperature range, i.e., 143-353 K. To facilitate the analysis, the spectra have intuitively been divided in three s...

Fuzzy logic and linguistic variables are used for the automatic interpretation of Raman spectra obtained from pigments found in cultural heritage art objects. Featured bands are extracted from a Raman spectrum of a reference pigment and the methodology for constructing the library is illustrated. An unknown spectrum is then interpreted automaticall...

Inelastic light scattering has been employed to study the effect of temperature on the medium-range structural order of glassy and supercooled selenium through its glass transition, i.e., over the temperature range 243–353 K. Raman spectra in the frequency range 4–430 cm-1 have been recorded and analyzed. Particular emphasis has been put on the fre...

“Rounding” effects and other specific changes of liquid sulfur’s polymerization transition are studied using Raman scattering in the case of fluid’s spatial confinement in nanonoporous sol-gel glasses. Specifically, in this paper we demonstrate the smearing or “rounding” of the monomer↔polymer transition caused by geometrical confinement of the liq...

In this paper we demonstrate the ability of inelastic (Raman) light scattering to probe polymerization transitions. We show that after proper treatment—that is, separating isotropic and anisotropic contributions and employing the reduced representation which removes the thermal population effect of vibrational energy levels—the Raman data can be us...

A new method is proposed for the estimation of the segmental orientation of vinyl or vinylidene polymers of moderate crystallinity by acquisition of only one Raman spectrum at a specific polarization geometry. A highly anisotropic rigid rod or/and resonant Raman-active guest-agent incorporated into a host-polymer can be easily detected at low conce...

The molecular orientation of uniaxially drawn commercial poly(vinyl chloride), PVC, specimens has been investigated by polarized Fourier transform infrared (FTIR) in the specular reflectance mode and by resonance Raman scattering in various combinations of sample orientation, scattering configuration and polarization geometry. The orientation was e...

Polymeric films of rigid−flexible luminescent polyethers containing substituted quinquephenyl units in the main chain and films of their diluted blends in polypropylene have been uniaxially drawn at temperatures above their glass transition. Polarized micro-Raman measurements have been conducted to evaluate the molecular orientation of the drawn po...