Toughening Immiscible Polymer Blends: The Role of Interface-Crystallization-Induced Compatibilization Explored Through Nanoscale Visualization.

This study explores the novel approach of interface-crystallization-induced compatibilization (ICIC) via stereocomplexation as a promising method to improve the interfacial strength in thermodynamically immiscible polymers. Herein, two distinct reactive interfacial compatibilizers, poly(styrene--glycidyl methacrylate)--poly(l-lactic acid) (SAL) and poly(styrene--glycidyl methacrylate)--poly(d-lactic acid) (SAD) are synthesized via reactive melt blending in an integrated grafting and blending process. This approach is demonstrated to enhance the interfacial strength of immiscible polyvinylidene fluoride/poly l-lactic acid (PVDF/PLLA) 50/50 blends via ICIC.

Infrared spectroscopy across scales in length and time at BESSY II.

The infrared beamline at BESSY II storage ring was upgraded recently to extend the capabilities of infrared microscopy. The endstations available at the beamline are now facilitating improved characterization of molecules and materials at different length scales and time resolutions. Here, the current outline of the beamline is reported and an overview of the endstations available is given.

infrared imaging of the local orientation of cellulose fibrils in plant secondary cell walls.

The mechanical and chemical properties of plant cell walls greatly rely on the supramolecular assembly of cellulose fibrils. To study the local orientation of cellulose in secondary plant cell walls, diffraction limited infrared (IR) micro-spectroscopic mapping experiments were conducted at different orientation of transverse leaf section of the grass with respect to the polarization direction of the IR radiation. Two-dimensional maps, based on polarization-sensitive absorption bands of cellulose were obtained for different polarization angles.

Vibrational signature of hydrated protons confined in MXene interlayers.

The hydration structure of protons has been studied for decades in bulk water and protonated clusters due to its importance but has remained elusive in planar confined environments. Two-dimensional (2D) transition metal carbides known as MXenes show extreme capacitance in protic electrolytes, which has attracted attention in the energy storage field. We report here that discrete vibrational modes related to protons intercalated in the 2D slits between TiCT MXene layers can be detected using operando infrared spectroscopy.

Synergy of Fiber Surface Chemistry and Flow: Multi-Phase Transcrystallization in Fiber-Reinforced Thermoplastics.

Fiber-reinforced polymer composites are largely employed for their improved strength with respect to unfilled matrices. Considering semi-crystalline materials under relevant processing conditions, the applied pressure and flow induce shear stresses at the fiber-polymer interface. These stresses may strongly enhance the nucleation ability of the fiber surface with respect to the quiescent case.

Occurrence of polycyclic aromatic hydrocarbons, microplastics and biofilms in Alqueva surface water at touristic spots.

Freshwater pollution is a huge concern. A study aiming to evaluate physico-chemical characteristics, microbiota, occurrence of two groups of persistent environmental pollutants with similar chemical properties (polycyclic aromatic hydrocarbons- PAHs and microplastics - MPs) in Alqueva's surface water was performed during 2021. Water samples were collected at three spots related to touristic activities (two beaches and one marina) during the Winter, Spring, Summer and Autumn seasons.

C-amidation of substitutedoligoamides yields novel supramolecular assembly motif.

N-acylated substitutedoligoamides are known to form unique supramolecular nanorods based on a 3-point hydrogen bond self-assembly motif. This motif is an intermolecular extension of the hydrogen bonding network that stabilizes the 14-helix secondary structure unique tooligoamides. Acetylation of the N-terminus of the molecule provides the necessary third hydrogen bond pair of the motif.

SAXS signature of the lamellar ordering of ionic domains of perfluorinated sulfonic-acid ionomers by electric and magnetic field-assisted casting.

At present, small angle X-ray scattering (SAXS) studies of perfluorinated sulfonic-acid ionomers (PFSAs) are unable to fully determine the true shape of their building blocks, as recent SAXS modelling predicts disk- and rod-like nanoionic domains as being equally possible. This scenario requires evidence-based findings to unravel the real shape of PFSA building blocks. Herein, a SAXS pattern signature for a lamellar nanophase separation of the ionic domains of Nafion is presented, backed by mid and far infrared spectroscopy (MIR and FIR) and wide angle X-ray scattering (WAXS) data of Nafion in different ionic forms, a broad range of ionic phase contents (EW ∼ 859-42 252 g eq-1) and temperatures.

Removal of Etalon Features in the Far-Infrared-Terahertz Transmittance Spectra of Thin Polymer Films.

Etalon features in infrared spectra of stratified samples, their influence on the interpretation, and methods to circumvent their presence in infrared spectra have been in discussion for decades. This paper focuses on the application of a method originally developed to remove interference fringes in the mid-infrared spectra for far-infrared Fourier transform spectroscopy on thin polymer films. We show that the total transmittance reflectance technique, commonly used for mid-infrared, also works successfully in the far-infrared spectral range where other approaches fail.

Féry Infrared Spectrometer for Single-Shot Analysis of Protein Dynamics.

Current submillisecond time-resolved broad-band infrared spectroscopy, one of the most frequently used techniques for studying structure-function relationships in life sciences, is typically limited to fast-cycling reactions that can be repeated thousands of times with high frequency. Notably, a majority of chemical and biological processes do not comply with this requirement. For example, the activation of vertebrate rhodopsin, a prototype of many protein receptors in biological organisms that mediate basic functions of life, including vision, smell, and taste, is irreversible.

Effects of temperature and pressure on the optical and vibrational properties of thermoelectric SnSe.

We have conducted a comprehensive investigation of the optical and vibrational properties of the binary semiconductor SnSe as a function of temperature and pressure by means of experimental and ab initio probes. Our high-temperature investigations at ambient pressure have successfully reproduced the progressive enhancement of the free carrier concentration upon approaching the Pnma → Bbmm transition, whereas the pressure-induced Pnma → Bbmm transformation at ambient temperature, accompanied by an electronic semiconductor → semi-metal transition, has been identified for bulk SnSe close to 10 GPa. Modeling of the Raman-active vibrations revealed that three-phonon anharmonic processes dominate the temperature-induced mode frequency evolution.

Tip-Enhanced Infrared Difference-Nanospectroscopy of the Proton Pump Activity of Bacteriorhodopsin in Single Purple Membrane Patches.

Photosensitive proteins embedded in the cell membrane (about 5 nm thickness) act as photoactivated proton pumps, ion gates, enzymes, or more generally, as initiators of stimuli for the cell activity. They are composed of a protein backbone and a covalently bound cofactor (e.g.

Interplay of α/β-Relaxation Dynamics and the Shape of Ionomer Building Blocks.

The relation between the α/β relaxations and the shape of the building blocks of ionomer materials is a key factor for programming an important temperature-dependent property: the memory of shape. However, the morphology of ionomers is indirectly obtained via modeling of small angle X-ray scattering (SAXS) data owing to the hardly accessible image characterization of the nanometric building blocks ‒ micelle-like cylindrical polymeric aggregates (radius ~2-6 nm and length >100 nm). Herein, broadband dielectric spectroscopy (BDS) measurements, free from electrode polarization effects, allowed identifying the time and temperature dependence of the polarization of different length scales of the ionomer matrix, and more importantly, by directly providing the aspect ratio of the radius and length of the polymeric aggregates for each desired temperature.

Heterogeneity of the Transmembrane Protein Conformation in Purple Membranes Identified by Infrared Nanospectroscopy.

Cell membranes are intrinsically heterogeneous, as the local protein and lipid distribution is critical to physiological processes. Even in template systems embedding a single protein type, like purple membranes, there can be a different local response to external stimuli or environmental factors, resulting in heterogeneous conformational changes. Despite the dramatic advances of microspectroscopy techniques, the identification of the conformation heterogeneity is still a challenging task.

Infrared dynamics study of thermally treated perfluoroimide acid proton exchange membranes.

The temperature induced dehydration process of the 3M Brand perfluoroimide acid (PFIA), an advanced proton exchange membrane for fuel cells, was studied by in situ infrared spectroscopy to understand proton transport processes under conditions of low hydration levels. A comprehensive assignment of the vibrational bands of PFIA in the mid infrared region is provided. Investigation of the kinetics in conjunction with 2D correlation spectroscopy methods revealed the sequential process of the hydration and dehydration in a conclusive model.

Time-resolved infrared spectroscopic techniques as applied to channelrhodopsin.

Among optogenetic tools, channelrhodopsins, the light gated ion channels of the plasma membrane from green algae, play the most important role. Properties like channel selectivity, timing parameters or color can be influenced by the exchange of selected amino acids. Although widely used, in the field of neurosciences for example, there is still little known about their photocycles and the mechanism of ion channel gating and conductance.

Stability and cytotoxicity of crystallin amyloid nanofibrils.

Previous work has identified crystallin proteins extracted from fish eye lenses as a cheap and readily available source for the self-assembly of amyloid nanofibrils. However, before exploring potential applications, the biophysical aspects and safety of this bionanomaterial need to be assessed so as to ensure that it can be effectively and safely used. In this study, crude crystallin amyloid fibrils are shown to be stable across a wide pH range, in a number of industrially relevant solvents, at both low and high temperatures, and in the presence of proteases.

Synchrotron Fourier transform infrared (FTIR) analysis of single living cells progressing through the cell cycle.

The application of FTIR spectroscopy to disease diagnosis requires a thorough knowledge of the spectroscopy associated with the cell cycle to discern disease markers from normal cellular events. We have applied synchrotron FTIR spectroscopy to monitor cells at different phases of the cell cycle namely G1, S and G2 phases. By applying Principal component analysis (PCA) from three independent trials we show clustering on a 2-dimensional scores plots (PC1 versus PC2) from cell spectra only two hours apart within the cell cycle.

High-spatial-resolution mapping of superhydrophobic cicada wing surface chemistry using infrared microspectroscopy and infrared imaging at two synchrotron beamlines.

The wings of some insects, such as cicadae, have been reported to possess a number of interesting and unusual qualities such as superhydrophobicity, anisotropic wetting and antibacterial properties. Here, the chemical composition of the wings of the Clanger cicada (Psaltoda claripennis) were characterized using infrared (IR) microspectroscopy. In addition, the data generated from two separate synchrotron IR facilities, the Australian Synchrotron Infrared Microspectroscopy beamline (AS-IRM) and the Synchrotron Radiation Center (SRC), University of Wisconsin-Madison, IRENI beamline, were analysed and compared.

Quantification of DNA in simple eukaryotic cells using Fourier transform infrared spectroscopy.

A technique capable of detecting and monitoring nucleic acid concentration offers potential in diagnosing cancer and further developing an understanding of the biochemistry of disease. The application of Fourier transform infrared (FTIR) spectroscopy has previously been hindered by the supposed non-Beer-Lambert absorption behavior of DNA in intact cells making elucidation of the DNA bands difficult. We use known composition DNA/hemoglobin standards to successfully estimate the DNA content in avian erythrocyte nuclei (44.

Microbeam-irradiated tumour tissue possesses a different infrared absorbance profile compared to broad beam and sham-irradiated tissue.

Purpose: To investigate biochemical changes in mouse tumour tissue following Microbeam Radiation Therapy (MRT) and Broad Beam (BB) irradiation using synchrotron Fourier-Transform Infrared (FTIR) microspectroscopy.

Materials And Methods: Synchrotron FTIR microspectroscopy was carried out on mouse tumour sections previously irradiated with BB (11, 22 or 44 Gy), MRT (560 Gy in-beam, 25 μm wide, 200 μm peak separation) or sham-irradiation (0 Gy) from mice culled 4 hours post-irradiation.

Results: MRT and BB-irradiated tumour sections showed clear chemical shifts in spectral bands corresponding to functional group vibrations in protein (1654-1630 cm(-1)), lipid (~1470, 1463 cm(-1)) and nucleic acid (1130-1050 cm(-1)).