Hydrophilic-hydrophobic Properties Research Articles

Oral In-Situ Nanoplatform with Balanced Hydrophobic-Hydrophilic Property for Transport Across Gastrointestinal Mucosa.

Transport of oral nanocarriers across the GI epithelium necessitates transport across hydrophilic mucus layer and the hydrophobic epithelium. Based on hydrophobic-hydrophilic balance, Curcumin-Lipomer (lipid-polymer hybrid nanoparticles) comprising hydrophobic stearic acid and hydrophilic Gantrez™ AN 119 (Gantrez) were developed, by a radical in-situ approach, to successfully traverse both barriers. A monophasic preconcentrate (Cur-Pre) comprising Cur(Curcumin), stearic acid, Gantrez and stabilizers, prepared by simple solution, was added to an aqueous phase to instantaneously generate Curcumin-Lipomer (Cur-Lipo) of nanosize and high entrapment efficiency (EE). Cur-Lipo size and EE was optimized by Box-Behnken Design. Cur-Lipomers of varying hydrophobic-hydrophilic property obtained by varying the stearic acid: Gantrez ratio exhibited size in the range 200-400nm, EE > 95% and spherical morphology as seen in the TEM. A decrease in contact angle and in mucus interaction, evident with increase in Gantrez concentration, indicated an inverse corelation with hydrophilicity, while a linear corelation was observed for mucopenetration and hydrophilicity. Cur-SLN (solid lipid nanoparticles) which served as the hydrophobic reference revealed contact angle > 90°, maximum interaction with mucus and minimal mucopenetration. The ex-vivo permeation study through chicken ileum, revealed maximum permeation with Cur-Lipo1 and comparable and significantly lower permeation of Cur-Lipo1-D and Cur-SLN proposing the importance of balancing the hydrophobic-hydrophilic property of the nanoparticles. A 1.78-fold enhancement in flux of hydrophobic Cur-SLN, with no significant change in permeation of the hydrophilic Cur-Lipomers (p > 0.05) following stripping off the mucosal layer was observed. This reiterated the significance of hydrophobic-hydrophilic balance as a promising strategy to design nanoformulations with superior permeation across the GI barrier.

Enhancement of Oral Bioavailability of Protein and Peptide by Polysaccharide-based Nanoparticles.

Oral drug delivery is a prevalent and cost-effective method due to its advantages, such as increased drug absorption surface area and improved patient compliance. However, delivering proteins and peptides orally remains a challenge due to their vulnerability to degradation by digestive enzymes, stomach acids, and limited intestinal membrane permeability, resulting in poor bioavailability. The use of nanotechnology has emerged as a promising solution to enhance the bioavailability of these vital therapeutic agents. Polymeric NPs, made from natural or synthetic polymers, are commonly used. Natural polysaccharides, such as alginate, chitosan, dextran, starch, pectin, etc., have gained preference due to their biodegradability, biocompatibility, and versatility in encapsulating various drug types. Their hydrophobic-hydrophilic properties can be tailored to suit different drug molecules.

Hydrophilic–Hydrophobic Properties of the Surface of Modified Carbonate Fillers for Asphalt

The physicochemical modification of the filler allows changing the hydrophilic–hydrophobic properties and effectively influencing the processes occurring at the filler–binder interface, on which the physicomechanical characteristics of composites largely depend. The paper presents studies related to the modification of limestone-based filler effect on the degree of its hydrophobicity and wetting with liquids of different polarity, establishing the relationship between the characteristics of hydrophobized mineral powders and the adsorption capacity in relation to water. Using mechanochemical processing with hydrophobic components GF-1 and GF-2, it was possible to obtain fillers with a sufficiently high content of hydrophobic particles (58.2% and 85.9%, respectively). It was found that the results of the contact angle (123.6° and 114.5°, respectively) and the degree of hydrophobicity do not quite correlate with each other. It was noticed that the contact angle on the powder modified with GF-1 decreases with time. Studies of the powders’ thermal effects wetting of different polarity liquids via microcalorimetry allows us to establish that with an increase in the filler hydrophobicity degree, the integral heat of immersion decreases due to a significant decrease in the probability of chemical interactions between water and powder due to the adsorption of applied surfactants molecules on the limestone active centers. The revealed endothermic effects indicate the occurrence of physical interactions due to non-polar dispersion forces. Differences in the nature of heat release and heat absorption in modified fillers indicate significant differences in the composition and mechanism of action of the used surfactants, which affected the efficiency of hydrophobization. At the same time, a linear dependence of the moisture absorption and moisture indicators, determined by independent experiments, on the degree of hydrophobicity was established.

Design of GSH-triggered disintegrable dendritic polyurethane as bioreducible unimolecular micelles for tumor-specific chemotherapeutic drug delivery

Unimolecular micelles have attracted intensely attention as drug delivery systems (DDSs) in tumor chemotherapy owing to their superior stability. However, their drug release performance is mainly determined by the hydrophilic-hydrophobic property of their cores, in which the chemotherapeutic drugs were loaded. Here, GSH-triggered disintegrable dendritic polyurethane was designed via a facile one-pot approach, with disulfide-containing diisocyanate. After PEGylation, it self-assembled into bioreducible unimolecular micelles with highly hydrophobic cores for chemotherapeutics-loading, showing a minimized premature drug leakage during blood circulation. After tumor cellular internalization, the GSH-triggered disintegration of the dendritic polyurethane-based cores in the unimolecular micelles occurred to release the loaded model drug (DOX), possessing tumor-specific chemotherapy with an enhanced tumor growth inhibition than free DOX.

Stimuli-Responsive Track-Etched Membranes for Separation of Water–Oil Emulsions

In this work, we have developed a method for the preparation of pH-responsive track-etched membranes (TeMs) based on poly(ethylene terephthalate) (PET) with pore diameters of 2.0 ± 0.1 μm of cylindrical shape by RAFT block copolymerization of styrene (ST) and 4-vinylpyridine (4-VP) to be used in the separation of water–oil emulsions. The influence of the monomer concentration (1–4 vol%), the molar ratio of RAFT agent: initiator (1:2–1:100) and the grafting time (30–120 min) on the contact angle (CA) was studied. The optimal conditions for ST and 4-VP grafting were found. The obtained membranes showed pH-responsive properties: at pH 7–9, the membrane was hydrophobic with a CA of 95°; at pH 2, the CA decreased to 52°, which was due to the protonated grafted layer of poly-4-vinylpyridine (P4VP), which had an isoelectric point of pI = 3.2. The obtained membranes with controlled hydrophobic-hydrophilic properties were tested by separating the direct and reverse “oil–water” emulsions. The stability of the hydrophobic membrane was studied for 8 cycles. The degree of purification was in the range of 95–100%.

The Effect of Structure of Porous Components of Electrochemical Devices on Their Characteristics (A Review)

Literature concerning the principal problems is analyzed. Basic characteristics of porous structures and methods of their determination are described, in particular, the pore distribution in radii, full porosity, the specific surface area, hydrophilic–hydrophobic properties. The effect of porous structure on the electrochemical characteristics of the following devices is discussed: lithium-ion and lithium-oxygen batteries, fuel cells with proton-exchange membrane, supercapacitors, electrodialyzers, and devices for water capacitive deionization (desalination).

Beta-Blocker Separation on Phosphodiester Stationary Phases—The Application of Intelligent Peak Deconvolution Analysis

Beta-blockers are a class of medications predominantly used to manage abnormal heart rhythms. They are also widely used to treat high blood pressure. From the liquid chromatography separation point of view, beta-blockers are interesting molecules due to their hydrophobic-hydrophilic properties. Thus, the study aimed to investigate the beta-blocker separation selectivity on four phosphodiester stationary phases in reversed-phase liquid chromatography (RP LC) and hydrophilic interactions liquid chromatography (HILIC). On tested stationary phases, beta-blockers provide retention in both chromatographic systems, RP LC and HILIC. Additionally, it was found that cation-exchange mechanisms have a significant contribution to retention. Separations were enhanced by applying ChromSword software for gradient optimization and Intelligent Peak Deconvolution Analysis to separate unseparated peaks digitally.

Multistage Modulation Formation of Hydrophilic–Hydrophobic Boron Carbon Nitride Nanomaterials

Boron carbon nitride (BCN) ternary compounds are attractive due to their wide applications in adsorption, catalysis, protective coatings, etc. A simple way is provided to synthesize BCN materials with multistage modulation of hydrophilic-hydrophobic properties. Hydrophilic BCN nanoparticles with a contact angle of 31° and nearly superhydrophobic BCN sheets with a contact angle of 145° are obtained. The participation of a CuO additive in the synthesis process has the role of tuning morphologies, components, and properties of BCN materials. The addition of CuO would improve the hydrophobicity of BCN due to its microstructure with enhanced surface roughness. The interaction between melamine and boric acid on the surface of CuO(111) is investigated by first-principles calculations based on density functional theory (DFT). The tuned BCN materials have different photoelectric properties also, and their performance as photocatalysts has been verified in photocatalytic reactions for hydrogen from water. The achieved uniform hydrophilic BCN nanoparticles and hydrophobic BCN sheets have the potential for further practical applications.

Polyamide 11 Composites Reinforced with Diatomite Biofiller—Mechanical, Rheological and Crystallization Properties

Amorphic diatomaceous earth is derived from natural sources, and polyamide 11 (PA11) is produced from materials of natural origin. Both of these materials show a low harmfulness to the environment and a reduced carbon footprint. This is why the combination of these two constituents is beneficial not only to improve the physicochemical and mechanical properties of polyamide 11 but also to produce a biocomposite. For the purpose of this paper, the test biocomposite was produced by combining polyamide 11, as well as basic and pre-fractionated diatomaceous earth, which had been subjected to silanization. The produced composites were used to carry out rheological (melt flow rate-MFR), mechanical (tensile strength, bending strength, impact strength), crystallographic (X-ray Diffraction-XRD), thermal and thermo-mechanical (differential scanning calorimetry-DSC, dynamic mechanical thermal analysis-DMTA) analyses, as well as a study of hydrophobic-hydrophilic properties of the material surface (wetting angle) and imaging of the surface of the composites and the fractured specimens. The tests showed that the additive 3-aminopropyltriethoxysilane (APTES) acted as an agent that improved the elasticity of composites and the melt flow rate. In addition, the produced composites showed a hydrophilic surface profile compared to pure polylactide and polyamide 11.

Aqueous Bubbles Stabilized with Millimeter-Sized Polymer Plates.

(Sub)millimeter-sized hexagonal polymer plates that were monodisperse in shape and size were utilized as stabilizers for aqueous bubbles, and the effects of the hydrophilic-hydrophobic property, size, and solid concentration of the plates on the formability, stability, and shape and structure of aqueous bubbles were investigated. The formability and stability of the bubbles were improved by increasing the hydrophobicity of the plate surface, decreasing the plate size, and increasing the solid concentration of the plates. For plates with suitable water wettability, three-dimensional bubbles with nearly spherical and polyhedral shapes were formed by the adsorption of plates to the bare air bubbles introduced into the continuous water phase by air-water mixing. On the contrary, two-dimensional bubbles with accordion-type structures consisting of alternating layers of plates and entrapped air bubbles were formed by the transfer of multiple plates with poor wettability from the air phase to the water phase by air-water mixing. Furthermore, a correlation was found between the bubble/stabilizer size ratio and bubble shape for plates with the suitable wettability: bubbles with nearly spherical shapes were formed when the bubble/plate size ratios were >2, bubbles with hexahedral, pentahedral, and tetrahedral shapes were formed when the size ratios were approximately 1, and bubbles with triangular and sandwich shapes were formed when the size ratios were <0.8. Additionally, bubbles with similar shapes were formed when the bubble/plate size ratios were close, even when the sizes of the plates and bubbles were different.

Preparation of cellulose acetate film with dual hydrophobic-hydrophilic properties using solution blow spinning

Solution blow spinning (SBS), a processing method alternative to electrospinning, where pressured air is used instead of an electric field, was used in this work for the preparation of cellulose acetate (CA) materials. The sequential use of SBS to produce a double-layered film is also investigated. Mixtures of acetone with acetic acid or N,N-dimethylformamide (DMF) were studied as systems for polymer solution preparation. The type of produced material (flat film or multi-structured membranes constituted from submicrometric fibers with beads), its thermal properties, crystallinity, and morphology are more dependent on the solvent system than other SBS processing parameters. Roughness and porosity of differently produced materials influence wettability measured by the contact angle, which ranges in this work from approx. 69.8° ± 3° for a flat film to 104° ± 5° for fibrous material. Finally, a double-layered film, prepared by sequential SBS of individual layers different in terms of wettability, renders a standalone film of dual wettability, with one side hydrophobic and the other hydrophilic.

Hydrophobic-Hydrophilic Properties and Characterization of PIM-1 Films Treated by Elemental Fluorine in Liquid Perfluorodecalin.

A direct fluorination technique was applied for the surface treatment of PIM-1 films in a liquid phase (perfluorodecalin). The fluorinated samples were analyzed by various instrumental techniques. ATR-IR spectroscopy showed that the fluorination predominantly takes place in methylene- and methyl-groups. Cyano-groups, aromatic hydrogens and the aromatic structure of the PIM-1 repeat unit were shown to be relatively stable at the fluorination conditions. XPS confirmed that the concentration of fluorine, as well as oxygen, in the near surface layer (~1 nm) increases with fluorination time. C1s and O1s surface spectra of the fluorinated PIM-1 samples indicated an appearance of newly-formed C-F and C-O functional groups. Scanning electron microscopy and X-ray energy-dispersive spectroscopy of the fluorinated PIM-1 samples showed an increase of the fluorine concentration at the surface (~0.1-1 μm) with the treatment duration. Analysis of the slices of the PIM-1 films demonstrated a decline of the fluorine content within several microns of the film depth. The decline increased with the fluorination time. A model of fluorine concentration dependence on the film depth and treatment duration was suggested. A change in the specific free surface energy as a result of PIM-1 fluorination was revealed. The fluorination time was shown to affect the surface energy (γSV), providing its shift from a low value (25 mJ∙m-2), corresponding to tetrafluoroethylene, up to a relatively high value, corresponding to a hydrophilic surface.

Supercapacitor Properties of rGO-TiO2 Nanocomposite in Two-component Acidic Electrolyte

The electrochemical properties of the highly porous reduced graphene oxide/titanium dioxide (rGO/TiO2) nanocomposite were studied to estimate the possibility of using it as a supercapacitor electrode. Granular aerogel rGO/TiO2 was used as an initial material for the first time of manufacturing the electrode. For the aerogel synthesis, industrial TiO2 Hombikat UV100 with a high specific surface area and anatase structure was used, and the aerogel was carried out with hydrazine vapor. Porous structure and hydrophilic-hydrophobic properties of the nanocomposite were studied with a method of standard contact porosimetry. This is important for a supercapacitor containing an aqueous electrolyte. It was found that the hydrophilic specific surface area of the nanocomposite was approximately half of the total surface area. As a result of electrochemical hydrogenation in the region of zero potential according to the scale of a standard hydrogen electrode, a reversible Faraday reaction with high recharge rate (exchange currents) was observed. The characteristic charging time of the indicated Faraday reaction does not exceed several tens of seconds, which makes it possible to consider the use of this pseudocapacitance in the systems of fast energy storage such as hybrid supercapacitors. Sufficiently high limiting pseudo-capacitance (about 1200 C/g TiO2) of the reaction was obtained.

Carbonate Lake Sediments in the Plastics Processing-Preliminary Polylactide Composite Case Study: Mechanical and Structural Properties.

In this study, the influence of carbonate lake sediments (Polylactide/Carbonate Lake Sediments–PLA/CLS) on the mechanical and structural properties of polylactide matrix composites was investigated. Two fractions of sediments originating from 3–8 and 8–12 m were analysed for differences in particle size by distribution (Dynamic Light Scattering–DLS), phase composition (X-ray Diffraction–XRD), the presence of surface functional groups (Fourier Transform-Infrared–FT-IR), and thermal stability (Thermogravimetric Analysis–TGA). Microscopic observations of the composite fractures were also performed. The effect of the precipitate fraction on the mechanical properties of the composites before and after conditioning in the weathering chamber was verified through peel strength, flexural strength, and impact strength tests. A melt flow rate study was performed to evaluate the effect of sediment on the processing properties of the PLA/CLS composite. Hydrophobic-hydrophilic properties were also investigated, and fracture analysis was performed by optical and electron microscopy. The addition of carbon lake sediments to PLA allows for the obtention of composites resistant to environmental factors such as elevated temperature or humidity. Moreover, PLA/CLS composites show a higher flow rate and higher surface hydrophobicity in comparison with unmodified PLA.

The mechanism of influence of polyvinyl alcohol (9 kDa) on the formation of ice crystals in aqueous solutions

Preventing crystallization of the liquid phase during freeze-thawing of cells is one of the main problems that need to be solved for the successful preservation of biomaterial at low temperatures. One highly effective recrystallization inhibitor is polyvinyl alcohol (PVA). However, the mechanisms of its cryoprotective effect have not been finally elucidated. In particular, it is not clear which structural features contribute to the realization of the antirecrystallization properties of PVA in the region of its cryoprotective concentrations. The influence of PVA on solvent crystallization and structural rearrangements of associations of PVA molecules in phosphate-buffered saline (PBS) was experimentally investigated. Solutions of PVA (molecular weight 9 kDa) in PBS were studied by cryomicroscopy and fluorescence spectroscopy methods. It was shown that molecular associations of PVA in PBS undergo a rearrangement of about 0.5−1 wt%, which is accompanied by a change in their size and hydrophilic-hydrophobic properties. PVA also changes the morphological structure of ice upon cooling and prevents crystallization upon heating. It is suggested that the mechanism of the antirecrystallization activity of PVA may be due to the formation of its complexes with the surface of ice crystals.

Adsorption of humic acid fractions by a magnetic ion exchange resin

Abstract Natural organic matter in waters varies in different fractions. To better understand the removal of different fractions by a magnetic ion exchange (MIEX) resin and the mechanism behind it, this study investigated adsorption kinetics, equilibrium and thermodynamics of humic acid (HA) fractions with different hydrophilic–hydrophobic properties and molecular weights on MIEX resin through a series of batch experiments. MIEX resin can effectively remove approximately 40% of hydrophilic and 30% of hydrophobic HA components, as well as approximately 44% of molecular weight (MW) &amp;lt;10 kDa to some degree. The removal efficiency of HA fractions by MIEX resin reduced with the increase of pH from 6 to 9. Adsorption kinetics of different HA fractions on MIEX resin fitted the pseudo-second-order model well. With the increase of MW of HA from &amp;lt;1 kDa to &amp;gt;10 kDa, the time to reach adsorption equilibrium reduced from 180 to 120 min. It took more time for the hydrophilic fractions (140 min) to reach the equilibrium than for hydrophobic HA fractions (120 min). The Sips model fitted the adsorption equilibrium data of HA fractions on MIEX resin well. It was revealed that the adsorption of HA fractions on MIEX resin was spontaneous, endothermic and an entropy driven process, and the chemisorption might dominate the adsorption of HA components on MIEX resin. This study is of great significance to the design of magnetic ion exchange resin reactors and the optimization of operational parameters for the removal of natural organic matter with different hydrophilic–hydrophobic properties and molecular weights in different water sources.

Nanofiber Material with Hydrophobic-Hydrophilic Properties Based on Poly(3-Hydroxybutyrate) and Poly(2-Hydroxyethyl Methacrylate)

A new material with hydrophobic-hydrophilic properties is obtained based on ultrathin poly(3-hydroxybutyrate) (PHB) fibers modified with poly(2-hydroxyethyl methacrylate). The supramolecular structure of the samples is investigated by structurally dynamic methods: scanning electron microscopy, differential scanning calorimetry, and electron paramagnetic resonance. The equilibrium-kinetic characteristics of water sorption by the material are determined. Evidence is obtained by the method of 1H NMR (proton nuclear magnetic resonance spectroscopy) for the chemical modification of the PHB surface due to the participation of its terminal groups in the transesterification reaction of 2-hydroxyethyl methacrylate.

ИССЛЕДОВАНИЕ ГИДРОФИЛЬНО-ГИДРОФОБНЫХ СВОЙСТВ ЭНТЕРОСОРБЕНТОВ РАЗЛИЧНОЙ ПРИРОДЫ

The analysis of the literature on the study of the technology of obtaining, physico-chemical properties of enterosorbents of various nature, widely used in the medical practice of the population of the Arctic: "Polysorb-MP", "Filtrum–STI", "Activated carbon". The physicochemical properties of enterosorbents have been studied by a complex of methods (low-temperature nitrogen adsorption method, elemental analysis, titrimetric analysis methods (determination of iodine number, determination of oxygen-containing groups on the surface of carbon black). Special attention is paid to the studies of hydrophilic-hydrophobic properties (moisture absorption) of enterosorbents using the desiccator method. The obtained results of the study for the enterosorbents "Polysorb-MP", "Filtrum–STI", "Activated carbon" are compared with the data obtained for the carbon enterosorbent "VNIITU-2", developed at the Center for New Chemical Technologies of the IC SB RAS.

Changes in hydrophobic-hydrophilic properties of chernozems under the influence of mineral fertilizers and their aftereffect

Soil samples and granulodensimetric fractions isolated from them ((silt particle size less than 1 µm, light fraction (LF) with a density of less than 2 g/cm3 and a fraction of the residues) of ordinary chernozem from experimental fields of the Kamennaya Steppe agricultural landscape of the Voronezh region were studied. The main differences between the variants of the experiment are introducing or stopping mineral fertilizers, and in the aftereffect of irrigation (13 years). There is an increase in the content of LF when using mineral fertilizers, as well as a change in the composition of sizedensity fractionations, expressed in different content of C and N and hydrophobic-hydrophilic components of humus substances (HS) of soils, silt and LF. The irrigation had practically no effect on the hydrophobichydrophilic composition of the initial soils, while the relative content of the hydrophilic components of the silt fraction of the soil increased, and the hydrophilic composition of HS LF decreased. The use of mineral fertilizers led to a significant variation in the degree of hydrophilicity of HS in silt and LF with a smaller change of this indicator for the HS of the soil as a whole. The abolition of fertilizers application, on the contrary, affected the hydrophobichydrophilic composition of the soil as a whole, and the composition of the soil silt and LF. The increase in the proportion of hydrophilic components in the composition of soil HS, as well as in the composition of HS silt and LF occurred simultaneously with an increase in the hydrophobicity of the surface of the solid phase of soil and with an increase in the carbon content in the soil, which indicates the stability of the system as a whole. Since the physical fractions of soils reacted more intensively to changes in the agrogenic load, compared with native soil samples, and changes in their qualitative composition were traced in two versions of the experiment, monitoring of hydrophobic-hydrophilic components of soil and soil granulodensimetric fractions is advisable to monitor and diagnose soil changes during agricultural use.

Effects of nisin and EDTA on morphology and properties of thermoplastic starch and PBAT biodegradable films for meat packaging

Biodegradable active packaging was produced by compounding nisin (3, 6 and 9%) and nisin-ethylenediaminetetraacetic acid (EDTA) (3 and 6%) mixtures with poly(butylene adipate terephthalate) and thermoplastic starch blends (PBAT/TPS) by blown-film extrusion. Nisin and EDTA interacted with polymers, involving CO stretching of ester bonds and increased compatibility. This plasticized the films and modified the crystallinity, surface roughness and thermal relaxation behavior. Barrier properties were improved due to modified hydrophilic-hydrophobic properties, compact structures and crystallites that restricted vapor and oxygen permeation. PBAT/TPS films containing EDTA and nisin effectively inhibited lipid degradation in pork tissues corresponding with stabilizing the CO ester bond of triacylglycerol. Microbial growth was also inhibited, particularly in EDTA-containing films up to 1.4 log. Inactivation of microorganisms stabilized redness and delayed meat discoloration, preserving the quality of packaged pork. Interaction between nisin, EDTA and polymers modified the morphology and film properties and functionalized biodegradable food packaging to inactivate microorganisms.