Hydrophobic Nanoparticles Research Articles

Facile Mechanochemical Functionalization of Hydrophobic Substrates for Single-Walled Carbon Nanotube Based Optical Reporters of Hydrolase Activity.

Single walled carbon nanotubes (SWCNT) have recently been demonstrated as modular, near-infrared (nIR) probes for reporting hydrolase activity; however, these have been limited to naturally amphipathic substrate targets used to noncovalently functionalize the hydrophobic nanoparticles. Many relevant substrate targets are hydrophobic (such as recalcitrant biomass) and pose a challenge for modular functionalization. In this work, a facile mechanochemistry approach was used to couple insoluble substrates, such as lignin, to SWCNT using l-lysine amino acid as a linker and tip sonication as the mechanochemical energy source. The proposed coupling mechanism is ion pairing between the lysine amines and lignin carboxylic acids, as evidenced by FTIR, NMR, SEM, and elemental analyses. The limits of detection for the lignin-lysine-SWCNT (LLS) probe were established using commercial enzymes and found to be 0.25 ppm (volume basis) of the formulated product. Real-world use of the LLS probes was shown by evaluating soil hydrolase activities of soil samples gathered from different corn root proximal locations and soil types. Additionally, the probes were used to determine the effect of storage temperature on the measured enzyme response. The modularity of this mechanochemical functionalization approach is demonstrated with other substrates such as zein and 9-anthracenecarboxylic acid, which further corroborate the mechanochemical mechanism.

Organic polymer composite with inorganic SiO2 particles for mechanical robustness and self-cleaning anti-reflective coatings

Anti-reflective coatings prepared from SiO2 nanoparticles have excellent anti-reflective properties, but the coating's poor mechanical properties and low self-cleaning performance limit its practical application. In this work, SiO2 nanoparticles were modified into hydrophobic particles using surface modification, and then organic polymer were added as a binder to formulate SiO2 sols, which were coated onto a glass substrate to form a anti-reflective coating. The coating can enable the glass substrate to achieve a transmittance of 99.1 % at 580 nm, and it can increase the average transmittance of the glass substrate from 89.6 % to 96.2 % in the 400–1100 nm band. In addition, the coatings prepared from hydrophobic SiO2 nanoparticles composite organic polymers have a water contact angle of 136°, resulting in good self-cleaning properties. The organic polymers can connect the SiO2 nanoparticles together, increasing the mechanical properties of the coating. This multifunctional anti-reflective coating with high transmittance, good mechanical properties and self-cleaning is beneficial in many applications, such as photovoltaic glass, architectural glass, displays and more.

Impact of laterally mobile surface charge on diffusiophoresis of hydrophobic rigid colloids

The diffusiophoresis of charged hydrophobic nanoparticles (NPs) governed by an imposed ionic concentration gradient is analysed. The main objective is to elucidate the impact of the laterally mobile adsorbed surface ions at the interface on the propulsion of the hydrophobic NPs in diffusiophoresis. In addition, the dielectric polarization due to the difference in dielectric constant between the NPs and the suspension medium is also considered. The mobile surface ions create a friction as well as an electric force at the hydrophobic surface, which leads to a modification of the slip velocity condition and the slip length. We obtain an exact numerical solution of the governing electrokinetic equations in their full form by adopting a control volume formulation. The numerical model is supplemented by analytical solutions derived based on the Debye–Hückel linearization. We find that the lateral mobility of the surface ions obstruct the coions to diffuse from the higher concentration side to the lower concentration side, which results in a repulsive force to the particle leading to the occurrence of a negative mobility. Based on the numerical results and analytical solutions, we have shown that for a fully mobile surface charge, the diffusiophoresis of a hydrophobic NP is identical to the diffusiophoresis of a liquid droplet whose viscosity is related to the slip length of the hydrophobic particle. We establish that the dielectric polarization enhances the velocity of a hydrophobic particle, which has potential applications in the practical context.

Research on the Mechanism of Nanoparticle materials in Oil Displacement and its Application

Abstract The application of nanoparticles in the field for enhanced oil recovery (EOR) is a new technology, which has attracted widespread concern. However, there is a lack of systematic research on the types and mechanisms. In order to clarify the types and characteristics of the material, oil displacement mechanism and its effect on oil and water flow, this paper systematically sorted out the classification of nanoparticle materials used in the field of petroleum development, and analysed its percolation and oil displacement mechanism. Numerical simulation and field data analysis were carried out to study the applications of two types of nanomaterials in improving reservoir water injection and oil displacement efficiency quantitatively. The results show that the main mechanism of nanoparticle flooding is to change reservoir wettability, reduce oil-water interfacial tension, modify the mobility ratio between water and oil phases, and reduce asphaltene precipitation. Lipophilic and hydrophobic nanoparticle may reduce injection pressure, and increases significantly injection in low permeability reservoirs, and the average water injectability of 6 wells is increased by 177.76%. The displacement efficiency of hydrophilic and oleophobic nanoparticles can be increased by 14.78%. This paper reveals the oil displacement mechanism of nanoparticle materials and establishes a new method to quantitatively predict the oil displacement effect of nanoparticle materials, which provides a basis and reference for the application of oilfield.

Efficient synthesis of highly hydrophobic lignin nanoparticles and their application as nano fillers for multifunctional composite membranes

Controlling the hydrophobic behaviors of lignin nanoparticles (LNPs) is crucial and advantageous for their application as film Nano Fillers, yet it poses a significant challenge. Herein, we successfully developed a novel method for the preparation of LNPs with highly hydrophobic behaviors using ternary deep eutectic solution (DES)-H2O systems. The resulting LNPs exhibit a significantly reduced content of hydrophilic groups on their outer surface, leading to a zeta potential value of only −4.9 mV, and up to 140.0° of water contact angle (WCA). Afterwards, a “Dissolution-Restructuration” mechanism was proposed to explain the formation of the prepared LNPs. Firstly, DES demonstrates superior H-bonding capabilities, facilitating the complete disruption of inter- and intramolecular H-bonding in lignin, and resulting in the formation of a highly homogenized lignin network. Subsequently, the DES system undergoes compromise after adding water, triggering the reformation of both inter- and intramolecular H-bonding and π-π interactions. Consequently, lignin orderly self-assembles into LNPs with highly hydrophobic characteristics. Especially, using the as-prepared LNPs as Nano fillers, a series of LNPs-containing polyvinyl alcohol (PVA) films were successfully fabricated, exhibiting exceptional hydrophobic behaviors (with contact angles reaching up to 124.0°). Furthermore, the mechanical strength, UV-shielding capabilities, and biodegradability of the PVA films are significantly enhanced. This study introduces a sustainable and efficient approach for the synthesis of hydrophobic LNPs, thereby facilitating the broadening of applications for lignin-based functional composite film materials.

Mixed Systems of Quaternary Ammonium Foam Drainage Agent with Carbon Quantum Dots and Silica Nanoparticles for Improved Gas Field Performance.

Foam drainage agents enhance gas production by removing wellbore liquids. However, due to the ultra-high salinity environments of the Hechuan gas field (salinity up to 32.5 × 104 mg/L), no foam drainage agent is suitable for this gas field. To address this challenge, we developed a novel nanocomposite foam drainage system composed of quaternary ammonium and two types of nanoparticles. This work describes the design and synthesis of a quaternary ammonium foam drainage agent and nano-engineered stabilizers. Nonylphenol polyoxyethylene ether sulfosuccinate quaternary ammonium foam drainage agent was synthesized using maleic anhydride, sodium chloroacetate, N,N-dimethylpropylenediamine, etc., as precursors. We employed the Stöber method to create hydrophobic silica nanoparticles. Carbon quantum dots were then prepared and functionalized with dodecylamine. Finally, carbon quantum dots were incorporated into the mesopores of silica nanoparticles to enhance stability. Through optimization, the best performance was achieved with a (quaternary ammonium foam drainage agents)-(carbon quantum dots/silica nanoparticles) ratio of 5:1 and a total dosage of 1.1%. Under harsh conditions (salinity 35 × 104 mg/L, condensate oil 250 cm3/m3, temperature 80 °C), the system exhibited excellent stability with an initial foam height of 160 mm, remaining at 110 mm after 5 min. Additionally, it displayed good liquid-carrying capacity (160 mL), low surface tension (27.91 mN/m), and a long half-life (659 s). These results suggest the effectiveness of nanoparticle-enhanced foam drainage systems in overcoming high-salinity challenges. Previous foam drainage agents typically exhibited a salinity resistance of no more than 25 × 104 mg/L. In contrast, this innovative system demonstrates a superior salinity tolerance of up to 35 × 104 mg/L, addressing a significant gap in available agents for high-salinity gas fields. This paves the way for future development of advanced foam systems for gas well applications with high salinity.

Magnetic lipid-poly(lactic-co-glycolic acid) nanoparticles conjugated with epidermal growth factor receptor antibody for dual-targeted delivery of CPT-11

To entrap sparingly water-soluble drugs like CPT-11 (irinotecan), the poly(lactic-co-glycolic acid) (PLGA) nanoparticle (NP) is highly favored due to its low cytotoxicity and approval for clinical use. On the other hand, entrapping hydrophobic oleic acid-coated iron oxide magnetic nanoparticles (OMNP) in PLGA NP can provide a nanovehicle for magnetically targeted drug delivery. Our goal in this study is to develop a new dual-targeted magnetic lipid-polymer NP for the delivery of CPT-11. We first co-entrap OMNP and CPT-11 in self-assembled lipid-PLGA NP to prepare OLNP@CPT-11. The OLNP@CPT-11 surface was modified with an epidermal growth factor receptor (EGFR) antibody Cetuximab (CET), which can actively target the overexpressed EGFR on the U87 glioblastoma cell surface. The OLNP-CET@CPT-11 enables dual targeting through both external magnetic guidance and CET-mediated active targeting. The NP was characterized for physicochemical properties using various analytical techniques. In vitro study confirms ligand-receptor interaction results in enhanced endocytosis of OLNP-CET@CPT-11 by U87 cells, which offers increased cytotoxicity and elevated cell apoptosis rates. Furthermore, magnetic guidance of OLNP-CET@CPT-11 to U87 cells can induce cell death exclusively in the magnetically targeted zone. The dual-targeted strategy also provides the best therapeutic efficacy against subcutaneously implanted U87 tumors in nude mice with intravenously delivered OLNP-CET@CPT-11.

Eco-friendly fabrication of robust superhydrophobic coating with excellent anti-corrosion and anti-icing properties through using submillimeter particles as protective structure

Constructing superhydrophobic surfaces is a promising method for enhancing the anti-corrosion and anti-icing properties of metal materials. However, it is still a challenge to obtain robust superhydrophobic surfaces on metal substrate through simple and environmentally friendly methods. In this study, a robust superhydrophobic coating was fabricated on an aluminum substrate using a simple two-step method, i.e., sprinkling B4C submillimeter particles onto the aluminum substrate coated with epoxy resin (EP) to construct submillitmeter protective structure, and then dipping a mixture of EP/polydimethylsiloxane (PDMS)/hydrophobic SiO2 nanoparticles to impart superhydrophobicity. The mechanical robustness of the coating was evaluated using sandpaper abrasion, 3 M tape peeling, and sand impact tests. The results displayed that the coating maintained its superhydrophobicity after 16 m of sandpaper abrasion (3.2 kPa), 60 cycles of 3 M tape peeling, and 2500 g of sand impact, indicating the good resistance of the coating to different mechanical damages. The anti-corrosion property of the coating was measured by the electrochemistry tests, and the results confirmed that the coating possessed excellent anti-corrosion property with 34.06 times lower corrosion current density than the bare aluminum. The anti-icing property of the coating was assessed by freezing delayed time and de-icing force tests, and the results demonstrated that coating had outstanding anti-icing property with 730 s longer freezing delay time and 3–4-folds lower de-icing force than the bare aluminum. It can be excepted that the coating has a promising prospect in practical application due to its simple fabrication, good anti-corrosion and anti-icing properties and remarkable mechanical robustness.

Hydrophobic ZIF-8 nanoparticles loaded on chitosan for improved methanol adsorption from fermented wine.

Metal-organic frameworks (MOFs) have great potential for the adsorption of minor molecular alcohols in the vapor phase. However, the drawbacks of powdered MOFs, including low recyclability and problematic separation, limit their application in fermented wine. Chitosan (CS) is a low-cost, eco-friendly, moldable matrix used in the food industry. In this study, a novel CS@ZIF-8 adsorbent with excellent microporous surface area was successfully synthesized by incorporating hydrophobic ZIF-8 into CS. The results showed that CS@ZIF-8 beads had a high adsorption affinity for methanol at a Zn2+/2-methylimidazole molar ratio of 1:5. The adsorption mechanism of methanol on CS@ZIF-8 beads was systematically studied by X-ray photoelectron spectroscopy, isotherms, and kinetics. The Langmuir model calculated the maximum adsorption of methanol to 56.8mg/g. Adsorption kinetics are consistent with pseudo-second-order models. Furthermore, CS@ZIF-8 beads presented excellent recyclability for removing methanol for five consecutive cycles. It could treat 60 bed volumes of Chinese yellow wine in column filtration experiments to make the concentration below 50mg/L. In summary, the highly efficient CS@ZIF-8 adsorbent has great potential for methanol adsorption from fermented wines. PRACTICAL APPLICATION: Methanol will exhibit adverse symptoms such as weakness and headaches after it is ingested. Therefore, methanol control is an important safety factor in the production of fermented wine. The adsorption method is recognized as a widely used technique due to its high efficiency and selectivity. The CS@ZIF-8 adsorbent synthesized in this paper provides a new idea for methanol removal.

Probing the Influence of Hydrophobicity of Modified Gold Nanoparticles in Modulating the Lipid Surface Behavior Using Vibrational Sum Frequency Generation Spectroscopy.

A deep understanding of how the surface modifications of nanoparticles impact their interactions with cell membranes is vital for advancing safe and effective biomedical applications. Among the pivotal factors governing these interactions, the hydrophobicity of nanoparticles plays a crucial role, predominantly driven by the hydrophobic interactions with the cell membrane. Herein, we study the influence of the hydrophobic alkyl chain length of thiol-capped gold nanoparticles (GNPs) on lipid surfaces with the help of vibrational sum frequency generation spectroscopy. We have utilized the zwitterionic 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) lipid monolayer as a representative model of cell membranes on the water surface. Our findings revealed that GNPs capped with the thiol ligand having a shorter alkyl chain such as heptanethiol (HT, C7) show minimal changes in the C-H stretching vibrations while interacting with the lipid monolayer. These observations could be attributed to the perturbation of the lipid chain due to hydrophobic-hydrophobic interactions between the alkyl chain of thiol-capped GNPs and the hydrophobic group of the lipid membrane or simply by the adsorption of GNPs at the interface without disrupting the monolayer structure. However, with increasing the chain length of thiol-capped GNPs from decanethiol (DDT, C10) to octadecanethiol (ODT, C18), the extent of spectral change in the C-H stretching vibration is increased. The controlled experiment performed with the deuterated lipids conforms that the changes observed in the C-H stretching vibration after adding HT (C7) GNPs are only because of their presence in the surface without altering the monolayer structure. However, in the case of DT (C10) and DDT (C12) GNPs, the strong hydrophobic interactions between the monolayer and the alkyl chain of the thiol-capped GNPs result in the increased orientational order of the monolayer. Moreover, in the case of ODT (C18) GNPs, the very long alkyl chain induces pronounced perturbations in the monolayer structure with net disordering of the monolayer. These observations are further supported by the spectral changes observed in the O-H vibration of the interfacial water molecules. Our findings reveal the crucial role of the hydrophobic nature of GNPs in influencing the interface. Understanding these effects is crucial for drug delivery applications and improving the stability and effectiveness of lipid-based systems.

Photofunctional gold nanocluster-based nanocomposite coating for enhancing anti-biofouling and anti-icing properties of flexible films

Elastomeric materials have garnered significant attention across biomedical and industrial fields. Multifunctionality and environmental stability are essential requirements for the application of these materials. Herein, we developed photofunctional gold nanocluster-based nanocomposites (SiO2-AuNC) and coated them on elastomeric polydimethylsiloxane (PDMS) films through one-step way to enhance anti-biofouling and anti-icing properties. The SiO2-AuNC coating, created by immobilizing ultra-small gold nanoclusters (AuNCs) onto hydrophobic silica nanoparticles surface using a gel-sol method, forms an island-like convex structure. The immobilization significantly enhanced radiative transitions and promoted the generation of reactive oxygen species of AuNCs, which provided robust anti-biofouling property through photosensitization to the films. Meanwhile, the rigid SiO2-AuNC nanocomposite markedly enhances the wear resistance of the films. Additionally, the hierarchical micro- and nanostructure of SiO2-AuNC coating increases the hydrophobicity of the films, effectively preventing the aggregation of supercooled water droplets, thereby providing superior and durably anti-icing properties. This one-step coating provides a simple and effective strategy for multifunctional surface modification with nanoparticles, showing potential biomedical and industrial applications.

Dual Biomimetic Synergistic Effects of Cactus Spines and Desert Beetle Shells for Water-In-Oil Emulsion Separation.

Drawing inspiration from the unique properties of cactus spines and desert beetle shells, we have designed a biomimetic stainless steel mesh specifically for efficient water-in-oil emulsion separation. The tapered arrays of cactus spines are prepared by a light-curing-templating method, and the hydrophobic regions are constructed by adhering hydrophobic silica nanoparticles to the surface of the mesh. This innovative design takes full advantage of the unique properties of these two natural plants, which can agglomerate tiny emulsified water to achieve an emulsion-breaking effect only under static conditions. At the same time, the stainless steel mesh with the conical arrays has a high water-in-oil emulsion separation efficiency (up to 99.6%), high permeance (2400 L·m-2·h-1·bar-1), and good cycling performance. The concept of dual biomimetic explored in this work may extend beyond oil-water separation to encompass various applications, such as fog collection, droplet manipulation, and more.

Preparation of mixed matrix membranes with PVP-induced fluorinated Zr-MOF for high-efficiency hydrogen purification under high humidity conditions

Given that hydrogen production often involves impurities such as CO2, CH4, H2O, and alkanes, hydrogen purification is crucial for global green energy applications. Mixed matrix membranes (MMMs) using metal-organic framework (MOF) materials offer a non-thermal, energy-efficient method for hydrogen purification. These membranes have controllable structures and promote environmental sustainability. However, challenges such as filler aggregation and matrix-filler incompatibility during the preparation of MOF-MMMs are difficult to avoid and can adversely affect separation performance. In this study, 4-(trifluoromethyl) benzoic acid (4-TFMBA) was introduced in situ to grow synchronously with polyvinyl pyrrolidone (PVP) on UiO-66-NH2, forming a hydrophobic bifunctional nanoparticle composite, PVP-Zr-MOF-F. Furthermore, in situ loading of PVP-Zr-MOF-F onto a PVDF polymer matrix was achieved using a wet method and the NIPS technique to prepare PVP-Zr-MOF-F@PVDF. The introduction of 4-TFMBA, with highly electronegative F atoms, enhances hydrophobicity and increases H2 affinity through polarization and hydrogen bonding induced by C–F bonds. PVP promotes the formation of smaller Zr-MOF particles, increases the proportion of small pores, prevents aggregation, and acts as a pore-forming agent, facilitating the in situ loading and dispersion of PVP-Zr-MOF-F within PVDF chains. This bifunctionalization not only improves the compatibility and dispersion of the nanofillers but also increases the number of small pores, enhancing van der Waals forces and confinement effects on H2 molecules, making it suitable for gas separation under humid conditions. The results indicate that the H2 permeance of PVP2–Zr-MOF-F@PVDF can reach 114,735 GPU, with selectivities of 19, 21, 24, and 120 for H2/CO2, H2/CH4, H2/C2H4, and H2/n-C6H14, respectively, surpassing the 2008 Robeson's upper bound. Notably, under high humidity conditions, the selectivities for H2/CO2, H2/CH4, and H2/n-C6H14 are 1566 %, 1891 %, and 3264 % higher than those of the original PVDF membrane, achieving high selectivity separation. Additionally, after repetitive experiments with varying humidity, the membrane's selectivity remained almost unchanged, demonstrating the high hydrothermal stability of PVP2–Zr-MOF-F@PVDF. This research provides a new reference for hydrogen purification and holds significant implications for the sustainable development of green energy.

Hydrophobic iron oxide nanoparticles: Controlled synthesis and phase transfer via flash nanoprecipitation

Iron oxide nanoparticles (IONPs) synthesized via thermal decomposition find diverse applications in biomedicine owing to precise control of their physico-chemical properties. However, use in such applications requires phase transfer from organic solvent to water, which remains a bottleneck.Through the thermal decomposition of iron oleate (FeOl), we systematically investigate the impact of synthesis conditions such as oleic acid (OA) amount, temperature increase rate, dwell time, and solvent on the size, magnetic saturation, and crystallinity of IONPs. Solvent choice significantly influences these properties, manipulating which, synthesis of monodisperse IONPs within a tunable size range (10-30 nm) and magnetic properties (75 to 42 Am2Kg-1) is obtained.To enable phase transfer of IONPs, we employ flash nanoprecipitation (FNP) for the first time as a method for scalable and precise size control, demonstrating its potential over conventional methods. Poly(lactic-co-glycolic acid) (PLGA)-coated IONPs with hydrodynamic diameter (Hd) in the range of 250 nm, high colloidal stability and high IONPs loadings up to 43% were obtained, such physicochemical properties being tuned exclusively by the size and hydrophobicity of starting IONPs. They showed no discernible cytotoxicity in human dermal fibroblasts, highlighting the applicability of FNP as a novel method for the functionalization of hydrophobic IONPs for biomedicine.

Nanoparticle transport in partially saturated porous media: Attachment at fluid interfaces

Like the solid-water interface (SWI), air-water and oil-water interfaces (AWI and OWI) also act as collectors for nano-sized particles in porous media. The attachment of hydrophobic nanoparticles, which is often favorable and irreversible, is of particular interest because the transport and retention of such particles is closely linked to the fate of nanoplastics in unsaturated subsurface environments and the success of nanoremediation practices. Here, we show how a pore-network model (PNM) can be used to upscale the kinetics and extent of irreversible nanoparticle attachment at a single fluid-fluid interface under conditions of advection and dispersion in a sphere packing. By focusing on a trapped (immobile) non-wetting phase, we highlight a fundamental difference between the single-collector contact efficiency of AWI/OWI and SWI. Namely, AWI/OWI collectors, which are largely by-passed by the flowing aqueous phase, are exposed to a hydrodynamic environment dominated by diffusion. This difference has profound implications for the modelling of nanoparticle transport in porous media at the continuum (Darcy) scale. This study reveals the potential of pore network modelling as an essential complement to continuum models for upscaling the behavior of nanocolloids in porous media.

Synthesis, characterization, and surface modification of degradable polar hydrophobic ionic polyurethane nanoparticles for the delivery of therapeutics to vascular tissue

Degradable polar hydrophobic ionic polyurethanes (D-PHI) are an emerging class of biomaterials with particular significance for blood-contacting applications due to their immunomodulatory effects and highly customizable block chemistry. In this manuscript, D-PHI polymer was formulated as a nanoparticle excipient for the first time by inverse emulsion polymerization. The nanoparticles were optimized with consideration of diameter, surface charge, size variability, and yield as a delivery vehicle for a custom vascular therapeutic peptide. A layer-by-layer (LBL) surface modification technique using poly-L-lysine was integrated within the nanoparticle design to optimize therapeutic loading efficiency. Solvent pH played a pivotal role in emulsion micelle formation, LBL polymer secondary structure, and the polymer functional group interactions critical for high therapeutic loading. The resulting nanoparticle platform met target size (200 ± 20 nm), polydispersity (<0.07), and storage stability standards, was nontoxic, and did not affect therapeutic peptide bioactivity in vitro. Surface-modified D-PHI nanoparticles can be reproducibly manufactured at low cost, generating a highly customizable excipient platform suitable for delivery of biomolecular therapeutics. These nanoparticles have potential applications in vascular drug delivery via localized infusion, drug eluting stents, and drug-coated angioplasty balloons. Statement of significanceNanoscale excipients have become critical in the delivery of many therapeutics to enhance drug stability and targeted biodistribution through careful design of nanoparticle composition, surface chemistry, and size. This manuscript describes the development of a nanoparticle excipient derived from an immunomodulatory degradable polar hydrophobic ionic polyurethane, in combination with a layer-by-layer surface modification approach utilizing poly-L-lysine, to transport a mimetic peptide targeting smooth muscle cell migration in vascular disease. The nanoparticle platform draws on the effect of pH to maximize drug loading and tailor particle properties. The low cost and easily reproducible system presents a highly customizable platform that can be adapted for therapeutic delivery across a wide range of clinical indications.

Facile Preparation of Silica/Tannic Acid/Zein Microcapsules Templated from Non-Aqueous Pickering Emulsions and their Application in Cargo Protection.

Microcapsules have attracted significant attention in academia and industry due to their unique properties for protecting and controlling the release of active substances. However, based on water-insoluble biopolymers, developing a straightforward approach to prepare microcapsules with improved biocompatibility and functional shells remains a great challenge. In this study, zein, a water-insoluble protein, is employed to prepare robust microcapsules facilely using oil-in-aqueous ethanol Pickering emulsions as templates. First, the emulsion template is stabilized by hydrophobic silica nanoparticles with in situ surface modification of tannic acid. The zein is then precipitated at the interface in a controlled manner using antisolvent approach to obtain silica/tannic acid/zein (STZ) microcapsules. It is found that the concentration of zein and the presence of tannic acid played a significant role in the formation of STZ microcapsules with well-defined morphology and a robust shell. The uniform deposition of zein on the surface of template droplets is facilitated by the interactions between tannic acid and zein via hydrogen bond and electrostatic force. Finally, the resulting STZ microcapsules showed super resistance to ultraviolet (UV) radiation and high temperature for the unstable, lipophilic, and active substance of β-carotene.

Development of Test Methods in the Process of Electrically Conductive Concrete Production

Abstract Prevention of climate change, implementation of sustainable development principles in building industry, creation of Green buildings, Three-zero buildings (zero energy, zero emissions, zero waste), energy independent buildings maybe on the base of Smart Concrete. Electrically Conductive Concrete as type of Smart Concrete have the possibilities to create multifunctional hybrid structures for various purposes. The production of electrically conductive concrete is usually based on the introduction of carbon materials and carbon nanomaterials (CNMs) as electrically conductive fillers into its concrete composition. The theory of conductive percolation is used for design of electrically conductive concrete. To select electrically conductive carbon filler, it is necessary to summarize their electrically conductive characteristics. Today, there is no standard for determining the electrical conductivity of carbon fillers, nor is there a method for designing the composition of electrically conductive concrete; the development of both is imperative. Features of the preparation of electrically conductive concrete with hydrophobic carbon nanoparticles prone to aggregation are indicated. To obtain high quality electrically conductive products an operating system for quality control at the stages of the technological process of manufacturing must be proposed. Homogenization of the electrically conductive filler is very important. It is necessary to propose a method for assessing the stability of an aqueous suspension of a hydrophobic carbon material used for homogeneous distribution of a filler. Due to the lack of a standard, a method for determining the electrical conductivity of concrete is also needed.

Sulfur fractionation using high-resolution continuum source molecular absorption spectrometry with calcium and hydrophobic palladium nanoparticles as chemical modifiers

The unprecedented use of high-resolution continuum source molecular absorption spectrometry (HR-CS MAS) for the fractionation of organic and inorganic sulfur (S) species through monitoring the CS molecule is presented here. Two separate methods for determining organic (CSorg) and inorganic (CSino) sulfur were developed to work sequentially. The optimized temperature program for both methodologies has two pyrolysis steps and one vaporization step (1st Tpyr: 1800 and 2ndTpyr: 800 °C, and Tvap: 2500 °C). The fractionation was achieved by implementing hydrophobic Pd NPs and Ca as chemical modifiers for the CSorg and CSino methods. Method development was performed by applying different statistical models, allowing the definition of optimal conditions for the chemical modifier mass, and minimizing the S species interconversion, i.e., Doehlert design, and central composite design. The limits of detection (LoD) for CSorg and CSino were 2.4 and 2.1 mg L−1, respectively. Recovery tests evaluated the method's specificity and accuracy; over 92 % recovery was found for both CSorg and CSino. Thus, the proposed methods offer a reliable alternative for fractionating organic and inorganic S by using HR-CS MAS.

Neutron and X-ray Scattering Characterization of Silica Nanoparticle-Stabilized Polymer Hybrid Latex Particles.

A robust route to produce poly(methyl methacrylate) (pMMA) hybrid latex particles (radius ∼250 nm) that are selectively "armored" with silica nanoparticles (radius 12.5 nm) through addition of vinyltriethoxysilane was previously shown ( J. Colloid Interface Sci. 2018, 528, 289-300).Depending on synthesis conditions, the extent of nanoparticle attachment could be varied; however, the mechanism behind this attachment during latex growth remained unclear. The dual population of particles present (silica + polymer) means that particle sizing by dynamic light scattering is ambiguous. Furthermore, the low glass transition temperature (Tg) of polymers such as poly(butyl acrylate) (pBA) typically used in film-forming applications for decorative coatings (i.e., paints) means that the hybrid latex particles are too "soft" for robust analysis through atomic force microscopy (AFM) and scanning electron microscopy (SEM). Here, we show that small- and ultrasmall-angle neutron scattering (SANS and USANS), along with complementary data from small-angle X-ray scattering (SAXS), reveals that these armored hybrid latex particles adopt a raspberry-type configuration, supporting their core-shell structure. The number of nanoparticles present on the surface of the hybrid latex can be adjusted by addition of one of a diverse range of alkyl- or perfluoroalkyl-silanes to alter silica nanoparticle hydrophobicity, and quantified through analysis of scattering data. The approach therefore provides a novel, nonperturbative, and in situ method of quantifying nanoparticle attachment to polymer latex particles.