Small-angle X-ray Scattering Analysis Research Articles

Sulfonated Pentablock Copolymer Membranes and Graphene Oxide Addition for Efficient Removal of Metal Ions from Water.

Nowadays heavy metals are among the higher environmental priority pollutants, therefore, the identification of new, effective, reusable and easy-to-handle adsorbent materials able to remove metal ions from water is highly desired. To this aim, in this work for the first time, sulfonated pentablock copolymer (s-PBC, Nexar™) membranes and s-PBC/graphene oxide (GO) nanocomposite membranes were investigated for the removal of heavy metals from water. Membranes were prepared by drop casting and their chemical, structural and morphological properties were characterized using scanning electron microscopy (SEM), Fourier transform infrared (FT-IR) spectroscopy, dynamic mechanical analysis (DMA) and small-angle X-ray scattering (SAXS). The adsorption abilities and adsorption kinetics of both the polymer and the s-PBC/GO nanocomposite were investigated for the removal of different heavy metal ions (Ni2+, Co2+, Cr3+ and Pb2+) from aqueous solutions containing the corresponding metal salts at different concentrations. The investigated s-PBC membrane shows a good efficiency, due to the presence of sulfonic groups that play a fundamental role in the adsorption process of metal ions. Its performance is further enhanced by embedding a very low amount of GO in the polymer allowing an increase by at least three times of the adsorption efficiencies of the polymer itself. This can be ascribed to the higher porosity, higher roughness and higher lamellar distances introduced by GO in the s-PBC membrane, as evidenced by the SEM and SAXS analysis. Both the polymeric materials showed the best performance in removing Pb2+ ions.

Stochastic models of dense or hollow nanoparticles and their scattering properties.

A family of stochastic models of disordered particles is proposed, obtained by clipping a Gaussian random field with a function that is space dependent. Depending on the shape of the clipping function, dense or hollow particles can be modelled. General expressions are derived for the form factor of the particles, for their average volume and surface area, and for their density and surface-area distributions against the distance to the particle centre. A general approximation for the form factor is also introduced, based on the density and surface-area distributions, which coincides with the Guinier and Porod expressions in the limits of low and high scattering vector magnitude q. The models are illustrated with the fitting of small-angle X-ray scattering (SAXS) data measured on Pt/Ni hollow nanoparticles. The SAXS analysis and modelling notably capture the collapse of the particles' porosity after being used as oxygen-reduction catalysts.

The use of a laponite dispersion to increase the hydrophilicity of cobalt-ferrite magnetic nanoparticles

In the literature, several attempts have been made to synthesize and later to modify magnetic nanoparticles to make them feasible for several applications. For biomedical applications, magnetic nanoparticles and clay minerals were combined to form a material that is both stable and biocompatible. In this context, composites with ratios of 4.70, 2.35 and 1.17 (weight/weight) of Cobalt Ferrite and Laponite were synthesized and characterized. These composites were treated with acid, and consequently the laponite was converted into an amorphous silica matrix around the magnetic nanoparticles. This morphology was confirmed using Fourier Transform Infrared Spectroscopy (FTIR) and X-ray Diffraction (XRD). The particle size distribution, obtained by Transmission Electron Microscopy (TEM), was used as an input parameter for the polydispersity function in the Small Angle X-ray Scattering (SAXS) analysis. The latter was also applied to verify the particle shapes and aggregates for each composite. It was demonstrated by Thermal Gravimetric Analysis (TGA), that these materials, except for the composite with the highest ratio, adsorbed at least one order of magnitude more water than pure Cobalt Ferrite nanoparticles. Thus, increasing the hydrophilicity properties of the Cobalt Ferrite - laponite/silica system. A preliminary magnetization experiment corroborated with these findings and showed that a fraction of the system is not in the superparamagnetic regime at room temperature.

On the amorphous layer in bone mineral and biomimetic apatite: A combined small- and wide-angle X-ray scattering analysis

The occurrence of an amorphous calcium phosphate layer covering the crystalline apatite core has been suggested to be an intrinsic feature of both bone mineral and synthetic biomimetic analogs. However, an exahustive quantitative picture of the amorphous-crystalline relationship in these materials is still missing. Here, we present a multiple scale modelling that combines small-angle X-ray scattering (SAXS) and synchrotron wide-angle X-ray total scattering (WAXTS) analyses to investigate the amorphous-crystalline spatial interplay in bone sample and biomimetic carbonated nano-apatites. SAXS analysis indicates the presence of a single morphology consisting of tiny nanoplates (NPLs) and provides a measure of their thickness (falling in the 3–5 nm range). WAXTS analysis was performed by developing atomistic models of apatite NPLs incorporating lattice strain, mostly attributed to the carbonate content, and calculating the X-ray patterns using the Debye Scattering Equation. Upon model optimization, the size and strain parameters of the crystalline platelets were derived and the amorphous component, co-existing with the crystalline one, separated and quantified (in the 23–33 wt% range). Notably, the thickness of the apatite core was found to exhibit nearly null (bone) or minor (< 0.5 nm, biomimetic samples) deviations from that of the entire NPLs, suggesting that the amorphous material remains predominantly distributed along the lateral sides of the NPLs, in a core-crown-like arrangement. The lattice strain analysis indicates a significant stiffness along the c axis, which is comparable in bone and synthetic samples, and larger deformations in the other directions. Statement of SignificanceCurrent models of bone mineral and biomimetic nanoapatites suggest the occurrence of an amorphous layer covering the apatitic crystalline nanoplates in a core-shell arrangement. By combining X-ray scattering techniques in the small and wide angle regions, we propose a joint atomic-to-nanometre scale modelling to investigate the amorphous-crystalline interplay within the nanoplates. Estimates are extracted for the thickness of the entire nanoplates and the crystalline core, together with the quantification of the amorphous fraction and apatite lattice strain. Based on the thickness matching, the location of the amorphous material mostly along the edges of the nanoplates is inferred, with a vanishing or very thin layer in the thickness direction, suggesting a core-crown-like arrangement, with possible implications on the mineral surface reactivity.

Understanding the Overcoated Catalyst Using in Situ Synchrotron X-Ray Techniques

Carbonaceous feeds, such as oil, gas, and coal, can be catalytically converted to useful products. Many of these reactions are conducted under harsh conditions, where the metal catalysts will rapidly sinter and lose activity. Overcoating is a methodology which preserves catalyst integrity under reaction conditions by depositing protective layers around the catalysts. Recently, we show that overcoating the metal nanoparticles with alumina using atomic layer deposition (ALD) will reduce the sintering and coking while the lifetime and reactivity of catalyst increase dramatically compared to the catalyst without ALD overcoating. It is believed that nano-sized pore (less than 2 nm) was formed during the calcination of ALD overlayer at high temperature. However, the mechanism of pore formation is still poorly understood due to the limited characterization technique.Understanding the mechanism of the pore formation and further controlling the pore size are crucial for the development of the ALD overcoated catalyst. Recently, we demonstrated that small angle X-ray scattering (SAXS) can be used to characterize these ALD overcoated catalysts. From SAXS analysis, the thermal treatment resulted in the formation of ~ 3.5 nm pores. Moreover, the evolution of pore size was monitored by in situ SAXS technique. The pore size increases with increasing annealing temperature. In this proposal, we aim to investigate the mechanism of pore formation during the calcination using in situ SAXS as well as wide angle X-ray scattering, to understand how the ramping rate, gas used, nature of supports and overcoated materials affect the formation of the pore.

Tetrameric Structures of Inorganic CBS-Pyrophosphatases from Various Bacterial Species Revealed by Small-Angle X-ray Scattering in Solution.

Quaternary structure of CBS-pyrophosphatases (CBS-PPases), which belong to the PPases of family II, plays an important role in their function ensuring cooperative behavior of the enzymes. Despite an intensive research, high resolution structures of the full-length CBS-PPases are not yet available making it difficult to determine the signal transmission path from the regulatory to the active center. In the present work, small-angle X-ray scattering (SAXS) combined with size-exclusion chromatography was applied to determine the solution structures of the full-length wild-type CBS-PPases from three different bacterial species. Previously, in the absence of an experimentally determined full-length CBS-PPase structure, a homodimeric model of the enzyme based on known crystal structures of the CBS domain and family II PPase without this domain has been proposed. Our SAXS analyses demonstrate, for the first time, the existence of stable tetramers in solution for all studied CBS-PPases from different sources. Our findings show that further studies are required to establish the functional properties of these enzymes. This is important not only to enhance our understanding of the relation between CBS-PPases structure and function under normal conditions but also because some human pathogens harbor this class of enzymes.

Conformational States of Exchange Protein Directly Activated by cAMP (EPAC1) Revealed by Ensemble Modeling and Integrative Structural Biology.

Exchange proteins directly activated by cAMP (EPAC1 and EPAC2) are important allosteric regulators of cAMP-mediated signal transduction pathways. To understand the molecular mechanism of EPAC activation, we performed detailed Small-Angle X-ray Scattering (SAXS) analysis of EPAC1 in its apo (inactive), cAMP-bound, and effector (Rap1b)-bound states. Our study demonstrates that we can model the solution structures of EPAC1 in each state using ensemble analysis and homology models derived from the crystal structures of EPAC2. The N-terminal domain of EPAC1, which is not conserved between EPAC1 and EPAC2, appears folded and interacts specifically with another component of EPAC1 in each state. The apo-EPAC1 state is a dynamic mixture of a compact (Rg = 32.9 Å, 86%) and a more extended (Rg = 38.5 Å, 13%) conformation. The cAMP-bound form of EPAC1 in the absence of Rap1 forms a dimer in solution; but its molecular structure is still compatible with the active EPAC1 conformation of the ternary complex model with cAMP and Rap1. Herein, we show that SAXS can elucidate the conformational states of EPAC1 activation as it proceeds from the compact, inactive apo conformation through a previously unknown intermediate-state, to the extended cAMP-bound form, and then binds to its effector (Rap1b) in a ternary complex.

Regulating Pore Structure of Hierarchical Porous Waste Cork‐Derived Hard Carbon Anode for Enhanced Na Storage Performance

AbstractPorous structure design is generally considered to be a reliable strategy to boost ion transport and provide active sites for disordered carbon anodes of Na‐ion batteries (NIBs). Herein, a type of waste cork‐derived hard carbon material (CC) is reported for efficient Na storage via tuning the pore species. Benefiting from the natural holey texture of this renewable precursor, CCs deliver a novel hierarchical porous structure. The effective skeletal density test combined with small angle X‐ray scattering analysis (SAXS) is used to obtain the closed pore information. Based on a detailed correlation analysis between pore information and the electrochemical performance of CCs, improving pyrolysis temperature to reduce open pores (related to initial capacity loss) and increase closed pores (related to plateau capacity) endows an optimal CC with a high specific capacity of ≈360 mAh g−1 in half‐cells and a high energy density of 230 Wh kg−1 in full‐cells with a capacity retention of 71% after 2000 cycles at 2C rate. The bioinspired high temperature pore‐closing strategy and the new insights about the pore structure–performance relationship provide a rational guide for designing porous carbon anode of NIBs with tailored pore species and high Na storage capacity.

Alkaline stability of model anion exchange membranes based on poly(phenylene oxide) (PPO) with grafted quaternary ammonium groups: Influence of the functionalization route

We study the effect of pendent methyl groups on the alkaline stability of model anion exchange polymers based on poly(2,6-dimethyl-1,4-phenylene)oxide (PPO) with grafted trimethylammonium groups. The polymer backbone is modified varying the synthesis procedure: by the bromination route, the ionomeric ammonium groups are inserted on the structural methyl group of PPO (Br-PPO-TMA), while by the chloromethylation route the ammonium groups are attached in the ortho-position to the methyl group of PPO (Cl-PPO-TMA). The properties of the membranes are studied by NMR and FTIR spectroscopy, thermogravimetry, water uptake, mechanical tensile tests, small-angle X-ray scattering (SAXS) and impedance spectroscopy. SAXS analysis indicates a better nanophase separation for Cl-PPO-TMA, which is consistent with a slightly larger water uptake and ionic conductivity. The properties of the two polymers are also compared before and after the aging in 2 M NaOH at 80 °C for different times. The thermogravimetric analysis shows the loss of the ammonium groups and the backbone ether cleavage after alkali treatments. The samples prepared by the bromination route show a higher stability of ionic conductivity, presumably due to a reduced alkaline attack of the ammonium groups, although DFT calculations do not show major differences of thermodynamic and kinetic reaction parameters. After alkaline treatment, the mechanical properties are more degraded for the Br-PPO-TMA compound. The decreased mechanical properties can be attributed to a reduction of the average chain length of PPO by alkaline scission of the ether links. Both synthesis routes have advantages and disadvantages, but the higher reproducibility and the better mechanical properties of samples prepared by chloromethylation are considered preponderant benefits.

Collagen structure changes during chrome tanning in propylene carbonate

Green solvents, such as propylene carbonate (PC), can be used in leather processing to improve the efficiency of chrome tanning and reduce wastewater. Here we report a combined small-angle X-ray scattering (SAXS) and differential scanning calorimetry (DSC) study on PC and its efficacy as a carrier medium during chrome tanning. SAXS analysis on the collagen structure of chrome tanned leather using PC, compared to conventionally tanned leather using water, showed an increase in Cr uptake in addition to the more uniform penetration of Cr through the leather cross-section. The increased binding of Cr to the collagen matrix drives the decreased hydration environment of the collagen triple helix. Furthermore, DSC studies show a uniform hydrothermal stability for the PC samples due to the more even distribution of Cr through the collagen matrix. Understanding the mechanisms by which chrome tanning occurs in non-aqueous solvents can guide us towards a more sustainable future for the leather industry.Graphical abstract

Development of a growth model for aluminum-doped zinc oxide nanocrystal synthesis via the benzylamine route

This work deals with time-resolved accessibility of suitable measurement technique to the solvothermal non-aqueous sol–gel synthesis of aluminum-doped zinc oxide (AZO) nanocrystals via the benzylamine route. Taking into account some limitations, we develop a new concept for using a lab-scale small-angle X-ray scattering (SAXS) camera to obtain detailed information about ongoing particle formation processes during AZO synthesis at the nanoscale range of 10 − 75 nm. Based on this concept, a new growth model is derived providing deep insights regarding process kinetics and morphological changes of AZO during growth. For this purpose, a new method is developed for carrying out and analyzing AZO synthesis in a low process temperature range (≪200 ° C) in order to achieve higher resolution of time-dependent particle formation processes by slowing down process speed. In detail, we show that the consumption of the zinc precursor during synthesis can be recorded by quantitative phase analysis (QPA) and thus validated with gravimetric analysis proving a pseudo-first-order process kinetics for the overall synthesis process. Taking into account the kinetics data, further transmission electron microscopy (TEM) and SAXS analyses are performed to investigate changes in terms of shape, size, and fractal properties leading into the development of a generalized growth model for AZO nanocrystals during synthesis.

Effect of dimethyl carbonate on the micromorphology and structure of combustion particles from diesel engines

ABSTRACTParticulate matter emitted by internal combustion engines is one of the main sources of air pollution. Oxygenated fuels can partially replace diesel fuel in combustion and reduce the emission level, especially the particulate matter emitted by diesel engines. In this paper, the emitted particles from the combustion of dimethyl carbonate (DMC)/diesel blends with different blending ratios were collected, and the effects of DMC on the morphology of the diesel particles were analyzed via scanning electron microscopy and small-angle X-ray scattering (SAXS) with a synchrotron radiation source. By studying the small-angle scattering intensity, particle size distribution, fractal dimension, and interface thickness of DMC/diesel combustion particles, the effects of DMC on the degree of agglomeration of particles, particle size distribution, and surface roughness were investigated. The results showed that as the DMC blending ratio increased, the radius of gyration of the particles decreased, the particle size of the primary carbon particles formed by combustion decreased, and the particle size distribution became narrower. With increasing DMC blending ratio, the electron density differences in the particles gradually decreased, the statistical average distance between the particles decreased, the fractal dimension increased, the degree of agglomeration increased, and the structural arrangement was more compact. SAXS analysis revealed that the combustion particles exhibited surface fractal characteristics at a wide angle range and exhibited mass fractal characteristics at a small angle range. The surface fractal dimension and mass fractal dimension of the particles were both higher than those of diesel particles, indicating that the surface roughness, irregularity, and degree of agglomeration of the particles all increased.

Synthesis of a Fluoromethacrylate Hydroxystyrene Block Copolymer Capable of Rapidly Forming Sub-5 nm Domains at Low Temperatures.

A series of poly(pentadecafluorooctyl methacrylate)-block-polyhydroxystyrene (PPDFMA-b-PHS) block copolymers (BCPs) were synthesized via reversible addition-fragmentation chain-transfer polymerization and subsequent deprotection. Because of the high incompatibility between hydroxyl groups and fluoro groups, the interaction parameter (χ) of these BCPs, determined by temperature-resolved small-angle X-ray scattering (SAXS), was extremely high. The χ value of PPDFMA-b-PHS was 0.48 at 150 °C, 16× larger than the χ of polystyrene-block-poly(methyl methacrylate). The microphase behavior of PPDFMA-b-PHS with various volume fractions of PHS block was determined by SAXS, yielding ordered lamellar morphologies with different sizes of domain spacing (d), and further confirmed by transmission electron microscopy. The minimum d obtained was 9.8 nm annealed at a mild temperature for a short time (80 °C for 1 min) by SAXS analysis, indicating the width of each lamellar domains was <5 nm.

Aliphatic copolyamide nanocomposites: Isothermal crystallization and crystalline morphology induced by clays

Isothermal crystallization of the nanocomposites based on aliphatic copolyamide (CoPA) containing bentonite (Btn), activated (K10) or organic modified montmorillonite (I30 P) clay were investigated using Differential Scanning Calorimetry (DSC) analysis. Results from the dynamic crystallization process denoted an improvement of the nucleation process, induced rather by K10 or I30 P clays than Btn clay. The data from isothermal crystallization were used to confirm a further reduction of kinetics and general crystallization rate in the CoPA matrix loaded with K10 and I30 P clays, despite already reduced crystallization kinetics of neat CoPA or loaded with Btn. It was proposed a two-dimensional growth mechanism of CoPA crystals induced by K10 and I30 P clays that was compared with a one-dimensional growth present in neat CoPA or filled with Btn clay. Small Angle X-Ray Scattering (SAXS) analysis of the isothermal crystallized samples had confirmed the morphology development and long period distribution in CoPA matrix. Furthermore, the SAXS results sustained a slight decrease in the clustering effect in the vicinity of clay interface. Consequently, the confinement effect induced by K10 and I30 P clays slowly increased the exfoliation level in these nanocomposites.

An alkaline active feruloyl-CoA synthetase from soil metagenome as a potential key enzyme for lignin valorization strategies.

Ferulic acid (FA), a low-molecular weight aromatic compound derived from lignin, represents a high-value molecule, used for applications in the cosmetic and pharmaceutical industries. FA can be further enzymatically converted in other commercially interesting molecules, such as vanillin and bioplastics. In several organisms, these transformations often start with a common step of FA activation via CoA-thioesterification, catalyzed by feruloyl-CoA synthetases (Fcs). In this context, these enzymes are of biotechnological interest for conversion of lignin-derived FA into high value chemicals. In this study, we describe the first structural characterization of a prokaryotic Fcs, named FCS1, isolated from a lignin-degrading microbial consortium. The FCS1 optimum pH and temperature were 9 and 37°C, respectively, with Km of 0.12 mM and Vmax of 36.82 U/mg. The circular dichroism spectra indicated a notable secondary structure stability at alkaline pH values and high temperatures. This secondary structure stability corroborates the activity data, which remains high until pH 9. The Small Angle X-Ray Scattering analyses resulted on the tertiary/quaternary structure and the low-resolution envelope in solution of FCS1, which was modeled as a homodimer using the hyperthermophilic nucleoside diphosphate-forming acetyl-CoA synthetase from Candidatus Korachaeum cryptofilum. This study contributes to the field of research by establishing the first biophysical and structural characterization for Fcs, and our data may be used for comparison against novel enzymes of this class that to be studied in the future.

Inherent Flexibility and Oligomerization of CLIC5A and CLIC6 - A Comparative Static and Dynamic Structural Study

Chloride intracellular channels (CLICs) are a family of unique metamorphic proteins. While exhibiting both soluble and transmembrane states, the molecular basis of their inherent flexibility remains largely unknown. Here, we present the high-resolution crystal structures of the human CLIC5A and mouse CLIC6. The structures reveal that both family members share monomeric arrangement in their soluble state with a high degree of structural conservation with other CLICs. Moreover, Small Angle X-ray Scattering (SAXS) analysis under reducing conditions demonstrates monomeric distribution in solution, reminiscent of the crystallized form. Importantly, Ensemble Optimization Method (EOM) analysis of the SAXS data revealed that both CLIC5A and CLIC6 can sample multiple conformations in solution, supporting the metamorphic classification of the family. CLICs were previously shown to incorporate into membranes and mediate ion conduction in vitro, suggesting multimerization upon membrane insertion. Here, we provide evidence for the ability of both CLIC5A and CLIC6 to undergo oxidation-dependent oligomerization in solution. However, comparative analyses of CLIC5A and CLIC6 revealed differential modes of oligomerization. While CLIC5A shows both cysteine-dependent and independent oligomerization, CLIC6 demonstrates only weak assembly which is cysteine-independent and highly enhanced by the presence of membrane mimetics. CLIC5A was suggested to play an important role in membrane remodeling processes. Interestingly, using both dynamic light scattering and fluorescence measurements, we demonstrate the ability of CLIC5A to mediate liposomal fusion in vitro, which is greatly enhanced by oxidative conditions. Together, these results provide insights into the structural conservation and inherent flexibility of CLICs and shed light on their regulation by changes in cellular redox potential as well as the molecular mechanisms associated with their possible roles during membrane remodeling.

Small-angle X-ray Scattering Analysis on Filler Dispersion State in Polymer Composite Prepared by Solvent Casting

Small-angle X-ray Scattering Analysis on Filler Dispersion State in Polymer Composite Prepared by Solvent Casting

Effects of Ionic Strength, Salt, and pH on Aggregation of Boehmite Nanocrystals: Tumbler Small-Angle Neutron and X-ray Scattering and Imaging Analysis

The US government currently spends significant resources managing the legacies of the Cold War, including 300 million liters of highly radioactive wastes stored in hundreds of tanks at the Hanford (WA) and Savannah River (SC) sites. The materials in these tanks consist of highly radioactive slurries and sludges at very high pH and salt concentrations. The solid particles primarily consist of aluminum hydroxides and oxyhydroxides (gibbsite and boehmite), although many other materials are present. These form complex aggregates that dramatically affect the rheology of the solutions and, therefore, efforts to recover and treat these wastes. In this paper, we have used a combination of transmission and cryo-transmission electron microscopy, dynamic light scattering, and X-ray and neutron small and ultrasmall-angle scattering to study the aggregation of synthetic nanoboehmite particles at pH 9 (approximately the point of zero charge) and 12, and sodium nitrate and calcium nitrate concentrations up to 1 m. Although the initial particles form individual rhombohedral platelets, once placed in solution they quickly form well-bonded stacks, primary aggregates, up to ∼1500 Å long. These are more prevalent at pH = 12. Addition of calcium nitrate or sodium nitrate has a similar effect as lowering pH, but approximately 100 times less calcium than sodium is needed to observe this effect. These aggregates have fractal dimension between 2.5 and 2.6 that are relatively unaffected by salt concentration for calcium nitrate at high pH. Larger aggregates (>∼4000 Å) are also formed, but their size distributions are discrete rather than continuous. The fractal dimensions of these aggregates are strongly pH-dependent, but only become dependent on solute at high concentrations.

Thermodynamic, rheological and structural properties of edible oils structured with LMOGs: Influence of gelator and oil phase

Abstract The effect of different oil phases and low molecular weight organogelators (LMOGs) structures on edible oils was investigated through differential scanning calorimetry (DSC), rheology and small-angle X-ray scattering (SAXS). Different gelators (glyceryl tristearate–GT; sorbitan tristearate–ST; sorbitan monostearate–SM and glyceryl monostearate-GM) were tested in medium-chain triglycerides and high oleic sunflower (named MCT and LCT). Systems were thermoreversible and their thermodynamic properties were dependent on the combined effect of the interactions of structurants’ polar head with other constituents and the sterical effect of their hydrophobic tails. The crystallization onset temperature was higher for GM and SM, possibly due to the lower sterical effect of their tails. However, the corresponding enthalpy and entropy change values were influenced by the hydrophilic head group: glycerol-based organogelator molecules were able to interact strongly than sorbitans, increasing these values. Rheological studies showed that gels produced with LCT were stronger than with MCT. Moreover, cooling and heating cycles showed more than one transition and shear dependence. Stronger structures were more sensitive to temperature, possibly because of their more organized structure that destabilizes more easily with the increase of molecular mobility. These results were in agreement with the SAXS analyses. At 50 °C, the stronger networks lost their initial structure, and at 70 °C they collapsed. Thus, molecular interactions and structurant self-assembly were dependent on the structurant + solvent combination, leading to different physicochemical properties and thermal stability. It is expected that these results will allow customizing properties of structured oil for diverse applications, spanning from food to cosmetic and pharmaceutical industries.

RETRACTED ARTICLE: A focus on the features of polyaniline nanofibres prepared via developing the single crystals of their block copolymers with poly(ethylene glycol)

Poly(ethylene glycol) (PEG)–polyaniline (PANI) diblock and triblock copolymers were synthesized via copolymerization of aniline with amine-terminated PEG by interfacial polymerization using sulphuric acid as dopant and ammonium peroxydisulfate (APS) as well as potassium hydrogen diiodate (PHD) as oxidants. The PHD-based synthesized PANI nanorods possessed longer lengths, narrower diameter distribution and higher conductivity. The electroactivity of synthesized copolymers was characterized using ultraviolet–visible (UV–Vis) spectrometry, cyclic voltammetry (CV) and resistivity measurement. Even in the presence of dielectric PEG blocks, the synthesized block copolymers had a conductivity around 3 S $$\hbox {cm}^{-1}$$ . In a further step, the solution-grown single crystals were prepared to investigate the general features of grafted PANI nanorods using small-angle X-ray scattering (SAXS), transmission electron microscopy (TEM) and atomic force microscopy (AFM). Based on AFM and SAXS analyses, the bimodal gel permeation chromatography (GPC) traces obtained from the block copolymers were originated from the diameter distribution of nanofibres, not from the dispersity of their lengths and molecular weights.