Hydrophobic Nanomaterials Research Articles

Improving the water-repellent properties of carbon nanotube-polycarbonate composites by introducing nanoscale patterns into the injection molding process

In this study, we explore the impact of hydrophobic nanomaterials, specifically carbon nanotubes (CNTs), on the water repellency of composite materials. These composites are prepared by combining multilayered or single-layered CNTs with polycarbonate (PC). Our goal was to develop highly water-repellent materials by directly forming nanopatterns on the surface through injection molding to enhance water repellency. Irrespective of the CNT type, widening the spacing between surface patterns and increasing the CNT concentration from 0 to 30 wt% resulted in a notable increase in the water contact angle to 161°, surpassing that of Teflon (108°). Moreover, in the multilayered CNT/PC system, a reduction in the sliding angle was observed compared to that of pure polycarbonate, demonstrating a lotus effect-like trend. Conversely, in the case of single-layered CNTs, despite an increase in the contact angle, the sliding angle did not decrease as significantly as in the multilayered CNTs. This implies that the superior transferability during the injection molding process of multilayered CNT/PC compared to single-layered CNT/PC is the underlying factor. This technology holds promise not only in the realm of mobility, such as in the aviation and automotive industries, but also in the medical field, with applications in microfluidic devices.

Entrapment and Voltage-Driven Reorganization of Hydrophobic Nanoparticles in Planar Phospholipid Bilayers.

Engineered nanoparticles (NPs) possess diverse physical and chemical properties, which make them attractive agents for targeted cellular interactions within the human body. Once affiliated with the plasma membrane, NPs can become embedded within its hydrophobic core, which can limit the intended therapeutic functionality and affect the associated toxicity. As such, understanding the physical effects of embedded NPs on a plasma membrane is critical to understanding their design and clinical use. Here, we demonstrate that functionalized, hydrophobic gold NPs dissolved in oil can be directly trapped within the hydrophobic interior of a phospholipid membrane assembled using the droplet interface bilayer technique. This approach to model membrane formation preserves lateral lipid diffusion found in cell membranes and permits simultaneous imaging and electrophysiology to study the effects of embedded NPs on the electromechanical properties of the bilayer. We show that trapped NPs enhance ion conductance and lateral membrane tension in 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) and 1,2-diphytanoyl-sn-glycero-3-phosphocholine (DPhPC) bilayers while lowering the adhesive energy of the joined droplets. Embedded NPs also cause changes in bilayer capacitance and area in response to applied voltage, which are nonmonotonic for DOPC bilayers. This electrophysical characterization can reveal NP entrapment without relying on changes in membrane thickness. By evaluating the energetic components of membrane tension under an applied potential, we demonstrate that these nonmonotonic, voltage-dependent responses are caused by reversible clustering of NPs within the unsaturated DOPC membrane core; aggregates form spontaneously at low voltages and are dispersed by higher transmembrane potentials of magnitude similar to those found in the cellular environment. These findings allow for a better understanding of lipid-dependent NP interactions, while providing a platform to study relationships between other hydrophobic nanomaterials and organic membranes.

Amphiphilic Nanointerface: Inducing the Interfacial Activation for Lipase.

Graphene-based materials are widely used in the field of immobilized enzymes due to their easily tunable interfacial properties. We designed amphiphilic nanobiological interfaces between graphene oxide (GO) and lipase TL (Thermomyces lanuginosus) with tunable reduction degrees through molecular dynamics simulations and a facile chemical modulation, thus revealing the optimal interface for the interfacial activation of lipase TL and addressing the weakness of lipase TL, which exhibits weak catalytic activity due to an inconspicuous active site lid. It was demonstrated that the reduced graphene oxide (rGO) after 4 h of ascorbic acid reduction could boost the relative enzyme activity of lipase TL to reach 208%, which was 48% higher than the pristine GO and 120% higher than the rGO after 48 h of reduction. Moreover, TL-GO-4 h's tolerance against heat, organic solvent, and long-term storage environment was higher than that of free TL. The drawbacks of strong hydrophobic nanomaterials on lipase production were explored in depth with the help of molecular dynamics simulations, which explained the mechanism of enzyme activity enhancement. We demonstrated that nanomaterials with certain hydrophilicity could facilitate the lipase to undergo interfacial activation and improve its stability and protein loading rate, displaying the potential of the extensive application.

In English

Неaling of infected ulcers and wounds, particularly in older people, is a serious problem in modern surgery. As a result of many years efforts, we have created an innovative wound care composition that has high absorptive, anti-inflammatory and wound-healing capabilities and are starting the clinical study of it. The composition, which got a trade mark Pathelen®, contains nanoscale hydrophilic silica (A-300), hydrophobic silica (Aerosil® R972 Pharma) and benzalkonium chloride. This work aimed to develop an optimal pathway of industrial production, as well as methods of quality control of the drug. The examination of manufacture intermediates and the final product includes bulk density measurement, thermal analysis, IR spectroscopy, chemical methods of identification, adsorption capacity and microbial contamination control. The pathway of manufacture which consists of mechanochemical immobilization of benzalkonium chloride on hydrophobic silica surface and mixing of obtained semi-product with hydrophilic nanoscale silica is developed. Thus, a technological method is proposed for combining hydrophilic and hydrophobic nanomaterials in one preparation. The final product complies to the elaborated quality parameters. In particular, the bulk density is distributed in a range 50–60 g/L, the adsorption capacity is not less than 140 mg of protein per gram. The absence of pathogenic microorganisms and fungi was demonstrated; the quantity of non-pathogenic microorganisms meets the requirements of the European Pharmacopoeia for products in this category. The results obtained can be useful for the organization a large-scale production of the proposed drug in future.

Surface Interactions Studies of Novel Two-Dimensional Molybdenum Disulfide with Gram-Negative and Gram-Positive Bacteria

The interaction between two-dimensional nanoflakes and bacteria in water-based physiological liquids is a hot topic that unveils new types of phenomena and is fundamental to bioscience applications. In this work, we extend Derjaguin, Landau, Verwey, and Overbeek theory (DLVO theory) that describes the properties of nano-objects in solutions, to the case of two-dimensional nanoflakes interacting with bacteria cell membranes, both for Gram-positive and Gram-negative bacteria. We have studied the role of the bacterial shape, membrane potential, and two-dimensional nanomaterials nature showing the interplay of these parameters in determining whether the interactions are attractive or repulsive and whether electrostatic or van der Waals forces are dominant. We calculated the interaction distances at equilibrium for different bacterial species and hydrophobic nanomaterials such as in two environmentally friendly solvents, water and cyrene.

Surface Modification of Polycaprolactone Scaffold With Improved Biocompatibility and Controlled Growth Factor Release for Enhanced Stem Cell Differentiation

Polycaprolactone (PCL) has been widely used as a scaffold material for tissue engineering. Reliable applications of the PCL scaffolds require overcoming their native hydrophobicity and obtaining the sustained release of signaling factors to modulate cell growth and differentiation. Here, we report a surface modification strategy for electrospun PCL nanofibers using an azide-terminated amphiphilic graft polymer. With multiple alkylation and pegylation on the side chains of poly-L-lysine, stable coating of the graft polymer on the PCL nanofibers was achieved in one step. Using the azide-alkyne “click chemistry”, we functionalized the azide-pegylated PCL nanofibers with dibenzocyclooctyne-modified nanocapsules containing growth factor, which rendered the nanofiber scaffold with satisfied cell adhesion and growth property. Moreover, by specific immobilization of pH-responsive nanocapsules containing bone morphogenetic protein 2 (BMP-2), controlled release of active BMP-2 from the PCL nanofibers was achieved within 21 days. When bone mesenchyme stem cells were cultured on this nanofiber scaffold, enhanced ossification was observed in correlation with the time-dependent release of BMP-2. The established surface modification can be extended as a generic approach to hydrophobic nanomaterials for longtime sustainable release of multiplex signaling proteins for tissue engineering.

Molecular insights into the resistance of phospholipid heads to the membrane penetration of graphene nanosheets.

The interaction between nanomaterials and phospholipid membranes underlies many emerging biological applications. To what extent hydrophilic phospholipid heads shield the bilayer from the integration of hydrophobic nanomaterials remains unclear, and this open question contains important insights for understanding biological membrane physics. Here, we present molecular dynamics (MD) simulations to clarify the resistance of phospholipid heads to the membrane penetration of graphene nanosheets. With 130 simulation trials, we observed that ∼22% graphene nanosheets penetrate the POPC bilayer. Sharp corners of the nanosheets should have a lower energy barrier than nanosheet edges, but interestingly, the membrane penetration mainly starts from the edge-approaching orientation. We thoroughly analyzed the pentration pathway and propulsion, indicating that the membrane penetration of graphene nanosheets is dominated by the joint effects of nanosheet edges and corners. Furthermore, the molecular origin of the resistance is clarified by evaluating the bilayers of different phospholipids, which successfully correlates the penetration resistance of phospholipid heads with the correlated motions of neighboring phospholipids for the first time. These results are expected to inspire future studies on the dynamic behavior of phospholipids, bio-nano interfaces, and design of biological nanomaterials.

Properties and behavior of light hydrophobic concrete

In concrete mixing plan, we usually encounter a combination of aggregates including sand, the amount of cement, which is actually the criterion of concrete grade, and the volume of water consumed. Changes in the quality and quantity of these components actually create the usual types of concrete. But the attitude that formed the basis of this research is based on the change in the nature of the components of the concrete mixing design. Removal of water and cement from the mixing plan and replacement of polymeric materials as well as the use of mixed LECA aggregates instead of aggregates is the basis of this research. In this paper, by examining and selecting LECA grain style and pre-treatment (hydrophobicity and coupling), in a constant ratio of resin, concrete samples were selected from three dimensional categories. After making the samples, flexural strength test was performed on them and the results were analyzed. Various compounds and processes have so far been proposed in the lightweight concrete mixing scheme. The distinctive point of this study is the use of lightweight expanded clay concrete with heat-treated acrylic polymer (crosslinking constituents) and related coupling agents. It is also important to select and apply the right amount of hydrophobic nanoparticles for hydrophilic surface hydrophobicity. Hydrophobicity was possible due to the non-polar nature of the acrylic polymer and the use of hydrophobic nanomaterials.

Study on Nano-Materials Improving Fracturing Fluid Performance and Oil Displacement Mechanism

Because of its characteristics and advantages, nano-materials can significantly improve the performance of fracturing fluid after being added to fracturing fluid. The research on the action mechanism of nano-materials in fracturing fluids is the theoretical basis and basis for developing functional fracturing fluids. At the nanoscale (50nm), SiO2 was modified with C8 and quaternary ammonium salt (QAS),synthesizing the Hydrophobic nano-materials SiO2-C8 and hydrophobic charged nanomaterials SiO2-QAS .The dispersion method, addition amount, compatibility stability and rheological properties of SiO2, SiO2-C8 and SiO2-QAS nano-materials in SRFP clean fracturing fluid system were studied. By means of quantitative simulation methods, the adsorption structure model and adsorption kinetics of nano-materials on sandstone surface were established The model analyzes the adsorption and oil-water separation characteristics of nano-materials on the sandstone surface. The research results show that the three nano-materials have better dispersion stability in the clean fracturing fluid, can effectively reduce the surface tension of the fracturing fluid, and show better temperature and shear resistance; Due to the special adsorption characteristics and specific interface effects of SiO2-C8 and SiO2-QAS nano-materials, which are beneficial to the replacement of oil molecules on the sandstone surface after the addition of fracturing fluid, and promote the separation of oil and water. The addition of SiO2-C8 and SiO2-QAS nano-materials can effectively improve the performance of fracturing fluid, improve the oil displacement effect on the surface of sandstone, and achieve the purpose of reducing oil saturation and increasing the fluidity of crude oil within the range of fracturing fluid. The results can be used as a reference for the development of functional fracturing fluid and the progress of fracturing technology for tight oil and shale oil.

Ultrafast assembly and healing of nanomaterial networks on polymer substrates for flexible hybrid electronics

High throughput manufacturing of regenerable nanomaterial-based flexible electronics represents an extreme challenge. Here we demonstrate a rapid and eco-friendly assembly and regeneration of nanomaterial networks (films) on a hydrophobic polymer substrate (i.e., polydimethylsiloxane) from a sonicated dispersion of hydrophobic nanoparticles in water. The self-limiting sono dip coating (SDC) assembly is characterized by an ultrafast withdrawal speed (16 m/min, one to five orders of magnitude greater than that of existing nanomaterial dip-coating processes) and insensitivity to substrate geometry. It is applicable to a wide range of hydrophobic nanomaterials, from graphene to carbon nanotubes and poly (methyl methacrylate) nanoparticles. The sono healing method requires only 1 min sonication in water to regenerate graphene/polydimethylsiloxane strain sensors. Furthermore, the SDC can be combined with other nanomaterial deposition methods (e.g., electroplating) to build heterostructures and integrated devices.

Surfactants: Recent advances and their applications

Surfactants have been widely used in many industrial products such as detergents, medicines, and anti-corrosive treatments due to their unique structures consisted of two different molecular parts and the broad range of selection. Surfactants have also contributed significantly to many research fields, especially in nanotechnology. For example, the amphiphilic nature of surfactants has been exploited to stabilize hydrophobic nanomaterials in water, affording access to a plethora of solution-processed nanomaterial-based scalable applications. Surfactants are also a key additive in the production of well-controlled nanoparticles. Surfactant-assisted metallic nanoparticle production has enabled the realization of colorimetric sensors, which are of massive interest in numerous interdisciplinary applications owing to their simplicity, practical applicability, cost-effective production, high stability, and high selectivity. Surfactants added during nanoparticle synthesis play a critical role in optimizing the sensor sensitivity and selectivity because they directly affect the nanoparticle properties. Further, a new category of surfactants with magnetic properties has been introduced for drug delivery applications. In this short review, we provide an overview of the fundamentals of surfactants and their applications for the development of nanotechnology.

Droplet-based Microfluidic Device for the Synthesis of Silica Nanoparticles

Microfluidic reactors are advantageous for nanomaterial synthesis due to their capability to provide controlled reaction environment. In this work, a droplet based microfluidic reactor is designed for the synthesis of silica nanoparticles. The synthesis is carried out in a very controlled environment and a uniform size and shape distribution is achieved. The classical synthesis protocol for silica nanoparticles is modified to use nonpolar solvents in the reaction so that this platform can later be used for coating hydrophobic nanomaterials. Therefore, this study not only presents a new device but also a new synthesis method. The results are compared with conventional batch wise synthesis methods and the obtained nanoparticles showed better size distribution.

Electrohydrodynamic Sprayable Amphiphilic Polysaccharide-Clasped Nanoscale Self-Assembly for In Vivo Imaging.

The work presented in this report demonstrates that amphiphilic polysaccharide-clasped self-assembly (Amp-SA) with nanometer size, encapsulating hydrophobic nanoparticles (NPs) can be generated via electrohydrodynamic spraying. It is observed that the formation of hydrophobic NP-encapsulated Amp-SA is dependent on the surface chemistry of NPs. The citrate-coated magnetic NPs (MNPs-Cit) were also prepared and compared. The hydrophobic magnetic NP-encapsulated Amp-SA (Amp-SA-M) exhibited around 2.7-2.8-fold higher values in r2 relaxivity than that of MNPs-Cit. In addition, the resulting Amp-SA-M achieved ∼17.2-fold higher values in r2/r1 ratios than MNPs-Cit. The enhanced performances in magnetic transverse (r2) relaxivity and r2/r1 ratio as well as the in vivo behavior of Amp-SA-M suggest the potential of Amp-SA-M as a promising MRI nanoprobe. This approach based on the nature-originated amphiphilic biopolymers may provide a novel insight into electrohydrodynamic techniques that have the ability to create various nanostructures, encapsulating high-quality hydrophobic nanomaterials for applications in diverse biotechnology.

Recent advances on regiocentric homo-epitaxial approaches in bio-mimetically derived artificial non-wettable surfaces

Abstract Natural biosurfaces shows water repellence mainly because of its unique surface roughness and peculiar chemical compositions. Herein, we have mimicked the properties of the natural, non-wettable surfaces and created artificial water repellent surfaces using perpendicularly aligned zinc oxide (ZnO) nanostructured coatings having rough surface texture. These non-wettable surfaces were prepared through simple seed assisted hydrothermal methods. In the present method, a seed layer of nano regime zinc oxide was initially prepared on clean glass slides by coating and calcination methods. The as-synthesized seed layer was utilized for the hydrothermal growth of vertically oriented nanostructures. The structural and functional features of the resultant samples were studied using XRD, FTIR, UV-Vis. spectrophotometer and Contact angle analyzer. The homo-epitaxial growth and the crystallinity of ZnO nano particles were assessed using XRD. The structural studies were performed using FTIR and the optical transparency studies of the samples were carried out using UV–Vis. spectrophotometer. Along with the photographic image analyses, the water contact angle analyses were performed to predict the non-wettable character of the resultant coatings. At low nutrient solution concentrations (10 mM) and at low seed solution concentrations (1–10 mM), hydrophobic nanomaterials surfaces with high water contact angle, ˃130°, were successfully prepared through the present hydrothermal methods that extends many practical applications in biomedical, defense and industrial sectors.

Magnetic solid-phase extraction of triclosan from water using n-octadecyl modified silica-coated magnetic nanoparticles

This study describes the preparation of core–shell magnetic nanoparticles coated with hydrophobic surface-modified silica as the magnetic solid-phase extractor of triclosan. A one-pot eco-friendly route is presented here. The cores (CoFe 2 O 4 , γ-Fe 2 O 3 and MnFe 2 O 4 ) were separately coated by a silica shell, which was then alkylmodified, both reactions in Stöber conditions. Characterizations involved FAAS, HRTEM, XRD, VSM, FTIR, contact angle, TGA, BET area, DLS and zeta potential. The hydrophobic nanoparticles presented nearly spherical magnetic cores of ∼13 nm and a silica shell thickness of ∼2 nm. The organofunctionalization was effective. The three hydrophobic nanomaterials adsorbed triclosan. Further experiments used CoFe 2 O 4 based nanomaterial. Analysis of the preconcentrated real sample by HPLC revealed a linear range of 0.4–102.4 μg L −1 , good linearity ( R 2 > 0.99), limit of detection and limit of quantification of 0.36 and 1.20 μg L −1 , respectively. The signal enhancement was 4.76. The nanoadsorbent was reused, maintaining its high performance.

Formation of Amphipathic Amyloid Monolayers from Fungal Hydrophobin Proteins.

The fungal hydrophobins are small proteins that are able to self-assemble spontaneouslyinto amphipathic monolayers at hydrophobic:hydrophilic interfaces. These protein monolayers can reverse the wettability of a surface, making them suitable for increasing the biocompatibility of many hydrophobic nanomaterials. One subgroup of this family, the class I hydrophobins, forms monolayers that are composed of extremely robust amyloid-like fibrils, called rodlets. Here, we describe the protocols for the production and purification of recombinant hydrophobins and oxidative refolding to a biologically active, soluble, monomeric form. We describe methods to trigger the self-assembly into the fibrillar rodlet state and techniques to characterize the physicochemical properties of the polymeric forms.

Water-Assisted Transfer Patterning of Nanomaterials.

We introduce a straightforward and cost-effective water-assisted approach to transfer patterns of nanomaterials onto diverse substrates. The transfer method relies on the hydrophobic effect and utilizes a water-soluble polymer film as a carrier to transfer hydrophobic nanomaterials from a patterned source substrate onto a target substrate. Using this approach, nanomaterials are transferred readily from solutions onto surfaces of various shapes and compositions with high fidelity for feature sizes approaching 10 microns.

Removal of Antimicrobial Peptides from Aqueous Solutions Using Carbon Nanotubes

The aim of this work is to study the possibility of removing antimicrobial peptides arenicin-1 and tachyplesin-1 from aqueous solutions using new highly hydrophobic nanomaterials—carbon nanotubes (CNTs) Taunit-M. Two types of CNTs, respectively, functionalized and nonfunctionalized with–COOH groups are studied. The RP HPLC method is used for the quantification of peptides in solutions before and after the sorption on the CNTs. It is revealed that tachyplesin-1 and arenicin-1 are actually not adsorbed on nonfunctionalized CNTs. A theoretical calculation of specific hydrophobicity and aliphatic index shows that both peptides have poorly expressed hydrophobic properties, and this can explain lack of their adsorption. On the contrary, using functionalized CNTs makes it possible to remove up to 89% of arenicin-1 and 92% of tachyplesin-1 from the solution. A comparative study of adsorption of the antimicrobial peptide tachyplesin- 1 on nonfunctionalized activated carbons and functionalized CNTs shows that the amount of peptide adsorbed on activated carbons is about three times less than that absorbed on CNTs. It is assumed that the high adsorption capacity of the functionalized CNTs toward the studied peptides results from the functionalization of the sorbent surface with the–COOH groups capable of forming ionic bonds with free–NH2 groups of peptides. This shows the prospects for using functionalized CNTs as sorbents for the removal of toxic preparations of peptide origin from aqueous solutions.

Examining the effect of different super hydrophobic nanomaterials on asphalt pavements

Annually large amounts of financial budgets are spent to improve the safety of the roads and airport runways in cold regions. One of the most important parameters in safety and reduction of accidents is the slipperiness of road surface during snowfall. The presence of ice and snow on the surface of the pavement increases the number of road accidents, and also causes the cancellation of flights. Thus, in order to reduce the adhesion of the ice and snow to the pavement and to eliminate them from the surface of the roads, using super hydrophobic coatings instead of traditional winter pavement maintenance methods can be a suitable solution. One of the main methods of detecting and evaluating hydrophobic surfaces is measuring the contact angle of the drop of water with the surface. For this purpose, the contact angle was measured in the presence of various hydrophobic coatings and with a specific weight percentage of sprayed material; and the consumption of 12 g of hydrophobic material was measured on 6 cm × 6 cm of asphalt samples. By examining the contact angle measured on the asphalt samples with 8 different hydrophobic materials; hydrophobic acrylate W4 with the chemical formula of (2,2,3,3,4,4,5,5-Octafluoropentyl methacrylate) has the largest angle contact so that on the average it increases the contact angle of asphalt surfaces from 75 to 156, and makes the asphalt pavement surface super hydrophobic.

Investigation of the synergistic effect of alumina nanofluids and surfactant on oil recovery – Interfacial tension, emulsion stability and viscosity reduction of heavy oil

ABSTRACTIn order to understand the synergistic effect of surfactants and nanofluids on enhancing recovery, hydrophilic and hydrophobic alumina nanomaterials were prepared for alumina nanofluids with surfactants. Oil-water interfacial tension and emulsion stability were investigated. The experimental results showed that nanofluids cooperated with surfactants could reduce oil-water interfacial tension in the proper concentration range, Nanoparticles decreased the average size of droplets, and restrained creaming and coalescence, therefore stabilizing the emulsion. The effect of nanofluids on the viscosity of heavy oil was also tested. The results indicated that the viscosity of heavy oil with surfactants was reduced by 42.8% when nanofluids were added at the shear rate of 10 s−1.