Halloysite Nanotubes Research Articles

A self-healing sustainable halloysite nanocomposite polyurethane coating with ultrastrong mechanical properties based on reversible intermolecular interactions

Endowing sustainable polyurethane (PU) materials with ultrastrong mechanical properties and highly efficient self-healing performancesimultaneously is extremely challenging and of great significance to dramatically extend the service life of metal materials. In this work, 4,4′-dithiodianiline (DTDA) and bio-based 2,5-Tetrahydrofurandimethanol (THFDM) were used as chain extenders to introduce hierarchical hydrogen bonds and aromatic disulfide bonds into the PU matrix, after which rich interfacial hydrogen bonds were obtained by incorporating environment-friendly polydopamine-modified halloysite nanotube (PDA@HNT) into the PU matrix. The developing PU nanocomposite exhibits record toughness (774.4 MJ m−3), outstanding tensile strength (68.3 MPa), and exceptional elongation at break (2882.7 %), as well as distinguished self-healing performance (85.4 % at 35 °C for 24 h; 95.9 % at 80 °C for 15 min). Thanks to the shielding effect of PDA@HNT fillers, the PU nanocomposite also possesses good corrosion resistance proved by its high impedance value at 0.01 Hz of 2.23 × 108 Ω cm2 after immersing in 3.5 wt% NaCl solution for 30 days. This work provides constructive guidance to create an ultra-robust self-healing sustainable PU nanocomposite with long-term corrosion resistance.

PVDF-Halloysite-Ceria multifunctional membrane for one-step treatment to industrial effluent

Industrial wastewater, containing diverse pollutants like dyes and oils, poses detrimental environmental challenges. Membrane technology addresses this complexity well but requires tailored nanofiller modifications that enhance hydrophilicity, oleophobicity, and antifouling potential for efficient separation. In this context, our work focuses on the development of mixed matrix membranes (PV-H-C) – PVDF, halloysite nanotubes (HNTs), and ceria nanoparticles – for effective dye and oil-water emulsion separation, enabling high flux recovery. The tubular structure of HNTs, with a lumen, enables the encapsulation and controlled distribution of ceria nanoparticles, preventing their agglomeration and leading to more uniform dispersion within the membrane matrix. HNTs porous structure, high surface area, and numerous adsorption sites within its nanotubes excel in rapid dye adsorption and ceria’s inherent hydrophobic properties along with low surface energy, forms a barrier against oil adhesion and spreading. Optimal results were achieved by loading 2% HNT and 1% ceria in the PVDF matrix, ensuring improved membrane performance. HNTs enhanced hydrophilicity and achieved pure water permeate flux of 1698 L/m2.h.bar. Developed membranes are super-oleophobic with an underwater contact angle of 132° + 3° and show a 100% increase in dyes and oils separation efficiency as compared to the pristine PVDF membranes. This unique integration of ceria with halloysite nanotubes in PV-H-C membranes is pivotal, bestowing exceptional anti-fouling characteristics and reusability, while providing a one-step, comprehensive solution for the effective treatment of complex industrial wastewater that encompasses both oil and complex dyes.

Influence of HNT-ZnO Nanofillers on the Performance of Epoxy Resin Composites for Marine Applications

Epoxy resin was conjugated with halloysite nanotubes (HNT) and different types of ZnO nanoparticles (commercial ZnO and modified ZnO-ODTES) to obtain HNT-ZnO/epoxy resin composites. These ZnO nanoparticles (ZnO NPs) were utilized with the intention to enhance the interfacial bonding between the epoxy resin and the reinforcing agent (HNT). The properties of resulted epoxy resin composites were characterized by various methods such as FTIR-ATR, TGA, DSC, TEM-EDX, and Nanoindentation analyses. The thermal properties of the epoxy resin composites were enhanced to a greater extent by the addition of HNT-ZnO nanofillers. DSC testing proved that the modification in the glass transition temperature can be due to the physical bonding between the epoxy resin and filler (HNT and/or ZnO). It was seen that the epoxy resin modified with HNT and ZnO-ODTES has the highest resistance to scratching by having a good elastic recovery as well as high values for surface hardness (~187.6 MPa) and reduced modulus (2980 MPa). These findings can pave the way for the developing of ZnO-based marine coatings with improved properties.

Halloysite nanotubes-based hybrid silica monolithic spin tip for hydrophilic solid-phase extraction of sulbactam, cefoperazone, and cefuroxime in whole blood

In this study, we proposed a novel method utilizing polyethyleneimine (PEI)-modified halloysite nanotubes (HNTs)-based hybrid silica monolithic spin tip to analyze hydrophilic β-lactam antibiotics and β-lactamases inhibitors in whole blood samples for the first time. HNTs were incorporated directly into the hybrid silica monolith via a sol-gel method, which improved the hydrophilicity of the matrix. The as-prepared monolith was further modified with PEI by glutaraldehyde coupling reaction. It was found that the PEI-modified HNTs-based hybrid silica monolith enabled a large adsorption capacity of cefoperazone at 35.7 mg g−1. The monolithic spin tip-based purification method greatly reduced the matrix effect of whole blood samples and had a detection limit as low as 0.1 − 0.2 ng mL−1. In addition, the spiked recoveries of sulbactam, cefuroxime, and cefoperazone in blank whole blood were in the range of 89.3–105.4 % for intra-day and 90.6–103.5 % for inter-day, with low relative standard deviations of 1.3–7.2 % and 4.9–10.5 %, respectively. This study introduces a new strategy for preparing nanoparticles incorporated in a hybrid silica monolith with a high adsorption capacity. Moreover, it offers a valuable tool to monitor sulbactam, cefoperazone, and cefuroxime in whole blood from pregnant women with the final aim of guiding their administration.

Construction of hyperbranched imprinted nanomaterials for selective adsorption of cadmium (II).

A hyperbranched ion-imprinted polymer (IIP) material containing multiple selective adsorption sites was synthesized using halloysite nanotubes, methyl acrylate, and ethylenediamine in the presence of a template ion [i.e. Cd (II) heavy metal]. The successful preparation of the Cd-IIP composition was confirmed by FT-IR, XRD, TEM, TGA, and elemental analysis. The polymers exhibited good adsorption of Cd (II) with a maximum adsorption capacity of 64.37 mg·g-1. The imprinting factor (α) for Cd (II) was 2.62 and the selection factor (β) was 1.78, indicating a specific adsorption of Cd (II) ion. The selection coefficients of Cd-IIP for Cd (II)/Pb (II), Cd (II)/Cu (II), Cd (II)/Ni (II), Cd (II)/Cr (III), and Cd (II)/Na (I) also indicated an excellent selectivity of the hyperbranched polymers for Cd (II) in the presence of competitive ions. The removal efficiency remained more than 75% after five cycles of desorption/adsorption. We envision that the HNTs based Cd-IIP has promising applications in the removal of Cd (II) from wastewater.

Prussian Blue/Polydopamine-Decorated Halloysite Nanotubes for Effective Bacterial Eradication via Photothermal-Enhanced Chemodynamic Therapy

Prussian Blue/Polydopamine-Decorated Halloysite Nanotubes for Effective Bacterial Eradication via Photothermal-Enhanced Chemodynamic Therapy

A new strategy to improve the anticorrosion performance of waterborne polyurethane coating on AA7075

In this study, Ce3+ functionalised halloysite nanotubes (HNTs) were prepared, and their impact on the anticorrosion properties of waterborne polyurethane (WPU) coating on 7075 aluminium alloy (AA7075) was investigated. HNTs were grafted by 3-aminopropyltriethoxysilane (APTES) to enhance Ce3+ loading, which was confirmed by X-ray diffraction (XRD) and Fourier-transform infrared (FT-IR) spectrum. The release behaviour of Ce3+ from HNTs was tested by inductively coupled plasma optical emission spectrometry (ICP-OES), and the inhibition effect of Ce3+-loaded HNTs for AA7075 was tested by polarization plots. The anticorrosion property of WPU doped with Ce3+-loaded HNTs was investigated by electrochemical impedance spectroscopy (EIS) and pull-off adhesion test. The results showed that APTES modification improved the Ce3+ loading amount on HNTs, and Ce3+ acts as an effective cathodic inhibitor for AA7075. After soaking for 40 days, the |Z|0.01Hz of Ce-HNTs/WPU was two orders of magnitude higher than that of pure WPU, while wet put-off adhesion was higher than pure WPU.

Covalently assembling multi-dimensional carbon-based nanoclay composites via ionic liquid linkers into PVA membrane for molecular separation

The application of membrane-based separation technology in purifying azeotropic solutions plays a crucial role in minimizing energy consumption during reactive distillation. The strategic integration of multi-dimensional structural composites within mixed matrix membranes (MMMs), characterized by a robust framework and efficient molecular transport channels, poses challenges but demonstrates significant potential for advancing the development of high-performance membrane fabrication. Herein, we proposed a novel strategy to covalently assemble halloysite nanotubes (HNTs) and graphene oxide (GO) using ionic liquids (ILs) as linkers. When incorporated into the polyvinyl alcohol (PVA) matrix, the ILs@HNTs@GO (IHGO) composites exhibit excellent interfacial compatibility, and ILs also enhanced the composite’s selective transfer ability to water molecules. The optimal separation performance for pervaporation dehydration from a ternary solution was respectively 2.57 (selectivity) and 1.74 (permeability) times higher than those of the pristine PVA membrane. The structural stability of the MMMs and their separation mechanism has been comprehensively validated by adjusting the content of GO in IHGO composites and conducting simulations. This study holds significant theoretical and practical implications for organic compounds purification, while simultaneously paving new avenues for the fabrication of structurally robust and high-performance MMMs with optimal filler effectiveness.

SINGLE-STAGE AND SIMPLE FABRICATION OF PE FILMS DECORATED WITH HALLOYSITE NANOTUBES

Background. Environmental pollution with plastic waste is a global problem that requires the search for effective and safe ways of disposal or processing of secondary raw materials. The use of catalysts for this purpose is a promising direction for research. Objective. In this work, a method of introduction of nanomaterials on the surface of a polyethylene film by partially dissolving the upper layer of the polymer in a heated nanomaterial suspension, namely aluminosilicate halloysite nanotubes in cyclohexane, was developed. Methods. Thermogravimetric, optical, and dynamic mechanical analyses of synthesised samples were carried out, and their properties were compared with reference samples of pure polyethylene and treated without the addition of nanomaterial. Results. It was achieved by the introduction of halloysite nanotubes in the amount of a maximum of 2.83 % by mass after immersion of the film in the suspension at a temperature of 50 °C for 120 seconds. The resulting film showed a wetting angle value of 77.11o, while for the reference sample without HNT it was 99.24o, which indicates the presence of hydrophilic nanotubes in the PE surface layer. Conclusions. At the same time, the synthesised samples showed a significant decrease in mechanical properties, such as elasticity and tensile strength, due to the destructive effect of the solvent on the polymer.

Fabrication of Polymeric Membrane with High Salt Rejection by Embedding Poly(Amidoamine) Dendrimer-Functionalized Halloysite Nanotubes

Fabrication of Polymeric Membrane with High Salt Rejection by Embedding Poly(Amidoamine) Dendrimer-Functionalized Halloysite Nanotubes

Preparation of efficient and eco‐friendly solid polymer electrolyte based on anionic polyurethane dispersion, polyethylene oxide, and halloysite nanotube

AbstractWith the ever‐increasing need for energy storage devices with high energy density, lithium (Li) metal anodes have been revisited. Due to the high reactivity of Li metal and the safety issues associated with liquid electrolytes, solid polymer electrolytes (SPEs) have gain attention. Polyethylene oxide (PEO) with the highest ionic conductivity (σ) among the polymers faces serious problems. The inability to meet the practical limit of σ due to its high crystallinity, and its low thermomechanical stability above its melting temperature, have limited its large‐scale application. In this research, anionic polyurethane dispersion (PUD) based on poly (ε‐caprolactone) (PCL) was synthesized and different PUD:PEO compositions was prepared using water as a solvent. Halloysite nanotube (HNT) was also used to improve the ionic conductivity by providing a new pathway for conducting lithium ions in the composition. The results corroborated that the presence of PUD stabilized the storage modulus of the host polymer above Tm of PEO. The ionic nature of the selected PUDs resulted in a transference number of 0.59 and the presence of HNT increased this value to 0.72. The presence of HNTs also led to a significant increase in σ by about three times compared to the control sample.

Electrospun polylactic acid nanofibers membrane with copper ion-loaded clay nanotubes for fresh-keeping packaging

The plastics derived from fossil fuels for food packaging results in serious environmental problems. Developing environment-friendly materials for food packaging is urgent and essential. In this study, polylactic acid (PLA) composite nanofibers membranes were prepared with good biocompatibility and antibacterial property. Cu2+ loaded in the natural halloysite nanotubes (HNTs) was used for the antibacterial agent. Cu2+ was loaded in the HNTs and was confirmed by the X-ray photoelectron spectroscopy (XPS). PLA nanofibers with different HNTs-Cu content were continuous nanofibers with the nanoscale range. HNTs-Cu entered into the nanofiber successfully. Thermal analysis results showed composite nanofibers had good thermal stability. Composite nanofiber membranes had the good hydrophobic property. HNTs-Cu improved the mechanical property of composite nanofibers than pure PLA nanofibers. Tensile strength and elasticity modulus of composite nanofibers with 4 % HNTs-Cu content were the most outstanding. L929 cells were cultured on the nanofiber membranes for biocompatibility evaluation. Cell viability of nanofiber membranes was above the 90 %. Cell live/dead staining results showed L929 cells was seldom dead on the nanofiber membranes. PLA/HNTs-Cu nanofiber membranes exhibited excellent antibacterial effects on S. aureus and E. coli. The inhibitory rates against S. aureus and E. coli were 98.31 % and 97.80 % respectively. The fresh-keeping effects of nanofiber membranes were evaluated by the strawberry preservation. Strawberries covered by nanofiber membranes exhibited better appearance, lower weight loss and higher firmness than control, PLA and PLA/HNTs groups. It promised that PLA/HNTs-Cu composite nanofiber membranes have the significant potential application for active food packaging.

Cefixime loaded bare and functionalized halloysite nanocarriers and their biomedical applications

Effective drug delivery for is the foremost requirement for the complete recovery of the disease. Nanomedicine and nanoengineering has provided so many spaces and ideas for the drug delivery design, whether controlled, targeted, or sustained. Different types of nanocarriers or nanoparticles are aggressively designed for the drug delivery applications. Clay minerals are identified as a one of the potential nanocarrier for the drug delivery. Owing to their biocompatibility and very low cytotoxicity, clay minerals showing effective therapeutic applications. In the present investigation, clay mineral, i.e., Halloysite nano tubes are utilized as a nanocarrier for the delivery of antibiotic cefixime (CFX), a third-generation cephalosporin. The HNT was first functionalized with the sulfuric acid and then further treated with the 3-(aminopropyl)triethoxysilane (APTES). The drug is loaded on three different classifications of HNTs, i.e., Bare-CFX-HNT, Acid-CFX-HNT, and APTES-CFX-HNT and their comparative analysis is established. Different characterization techniques such as X-ray diffractometry (XRD), Fourier transform infra-red (FT-IR), Transmission electron microscopy TEM), Brunauer–Emmett–Teller (BET), adsorption studies, and Thermogravimetric analysis (TGA) were performed to evaluate their chemical, structural, morphological, and thermal properties. TGA confirmed the encapsulation efficiency of Bare-CFX-HNT, Acid-CFX-HNT, and APTES-CFX-HNT as 42.65, 52.19, and 53.43%, respectively. Disk diffusion and MTT assay confirmed that the drug loaded HNTs have potential antibacterial activities and less cytotoxicity. The adsorption capacity of CFX with different HNTs are evaluated and Different adsorption and kinetic models have been discussed. Drug release studies shows that APTES-CFX-HNT showing sustained release of cefixime as compared to Bare-CFX-HNT and Acid-CFX-HNT.

Sustainable bioactive food packaging based on electrospun zein-polycaprolactone nanofibers integrated with aster yomena extract loaded halloysite nanotubes

Compostable zein-polycaprolactone (PZ) electrospun nanofiber integrated with different concentrations of Aster yomena extract loaded halloysite nanotubes (A. yomena-HNT) as bioactive nanofibrous food packaging is reported. SEM micrographs reveal heterogeneous nanofibers. A. yomena extract used in the study showed weak antioxidant activity with AAI and TEAC values of 0.229 and 0.346. In vitro, release profile over 7 days of A. yomena indicates a controlled, sustained, and prolonged release. The prepared nanofibers were effective against both gram-positive and gram-negative bacteria. The prepared composite nanofibers were rendered biocompatible and nontoxic when subjected to WST-1 and LDH assay after incubating with NIH 3T3 mouse fibroblast cell line. PZ-15 nanofiber packaging showed the best postharvest quality preservation in Black mulberry fruits after 4 days of storage at 25 °C and 85 % Rh. Moreover, the in vitro decomposition test reveals that the fabricated nanofibers decompose in the soil and do not pose as a threat to the environment.

Metalized Plastic Current Collectors Incorporated with Halloysite Nanotubes toward Highly Safe Lithium‐Ion Batteries

AbstractMetalized plastic current collectors (MPCCs) have shown potential in improving the energy density and safety of lithium‐ion batteries (LIBs). However, the poor mechanical strength, weak interfacial adhesion force, and surface metal corrosion have impeded the practical application of MPCCs. Here, an innovative engineering of MPCCs is proposed by incorporating halloysite nanotubes (HNTs) as fillers into polyimide (PI) polymer layer, which is further coated with two thin copper (Cu) layers. Because of the strong bonding between HNTs surface and the PI precursor, HNTs improve the mechanical strength of PI‐HNTs composite film, reinforce the interfacial adhesion force between the PI‐HNTs film and the coated Cu layer, and suppress the Cu corrosion by electrolyte. The prepared MPCCs exhibit a low mass density and only account about one‐fifth of the density of commercial Cu CCs. Furthermore, the PI‐HNTs‐Cu composite demonstrates significantly enhanced interfacial adhesion force doubled to 4 N cm−1 along with prolonged stability under electrolyte immersion and electrochemical reaction conditions, and delivers a high fracture strength of 125 MPa. LIBs assembled with MPCCs deliver a twice higher discharge capacity compared to battery with Cu CCs and reach a long‐term cycle capacity retention as high as 92.9% at 0.5 C after 500 cycles.

Hal-Py-SO3H as a novel and recyclable catalyst for highly efficient synthesis of xanthene and spiropyran derivatives

The aim of this research is to synthesize a new sulfonic acid catalyst based on halloysite nanotubes (Hal-Py-SO3H) and characterize it as a solid acid nanocatalyst by various analytical techniques such as Fourier-Transformed Infrared spectroscopy (FTIR), Thermal gravimetric Analysis (TGA), X-ray Diffraction (XRD) analysis, Scanning Electron Microscopy (SEM), Vibrating Energy-Dispersive X-ray analysis (EDX), Transmission electron microscopy (TEM) and X-ray atomic mapping. Furthermore, this new catalyst was evaluated in synthesizing spiropyran derivatives via multicomponent reactions (MCRs) and Xanthen derivatives under environmentally sustainable conditions. The main advantages of this approach include green conditions, excellent yields, quick reaction rates, and ease of preparation. Additionally it was observed that the catalyst exhibited robust stability even after multiple recycling processes, indicating its potential for practical applications in sustainable chemical transformations.

Magnetic biocomposite scaffold based on decellularized tendon ECM and MNP-deposited halloysite nanotubes: physicochemical, thermal, rheological, mechanical and in vitro biological evaluations

The development of new three-dimensional biomaterials with advanced versatile properties is critical to the success of tissue engineering (TE) applications. Here, (a) bioactive decellularized tendon extracellular matrix (dECM) with a sol-gel transition feature at physiological temperature, (b) halloysite nanotubes (HNT) with known mechanical properties and bioactivity, and (c) magnetic nanoparticles (MNP) with superparamagnetic and osteogenic properties were combined to develop a new scaffold that could be used in prospective bone TE applications. Deposition of MNPs on HNTs resulted in magnetic nanostructures without agglomeration of MNPs. A completely cell-free, collagen- and glycosaminoglycan- rich dECM was obtained and characterized. dECM-based scaffolds incorporated with 1%, 2% and 4% MNP-HNT were analysed for their physical, chemical, and in vitro biological properties. Fourier-transform infrared spectroscopy, x-ray powder diffractometry and vibrating sample magnetometry analyses confirmed the presence of dECM, HNT and MNP in all scaffold types. The capacity to form apatite layer upon incubation in simulated body fluid revealed that dECM-MNP-HNT is a bioactive material. Combining dECM with MNP-HNT improved the thermal stability and compressive strength of the macroporous scaffolds upto 2% MNP-HNT. In vitro cytotoxicity and hemolysis experiments showed that the scaffolds were essentially biocompatible. Human bone marrow mesenchymal stem cells adhered and proliferated well on the macroporous constructs containing 1% and 2% MNP-HNT; and remained metabolically active for at least 21 d in vitro. Collectively, the findings support the idea that magnetic nanocomposite dECM scaffolds containing MNP-HNT could be a potential template for TE applications.

Germ must be found: The HNT@RhB@MOF-Tb polychromatic fluorescent nanoprobe is applied for the visual detection of 2,6-dipicolinic acid

A polychromatic fluorescent nanoprobe based on natural halloysite nanotubes with fluorescent dyes and porous metal–organic frameworks co-loaded on the surface and inner wall of the nanotubes was constructed for the highly sensitive visual identification of the Bacillus anthracis biomarker 2,6-dichlorophenolic acid (DPA). The limit of detection for DPA was 11.27 nM, which is significantly lower than the spore-borne dose for anthrax infection (60 uM). The multi-color fluorescent probe showed potential for rapid, accurate, and highly selective detection of Bacillus anthracis markers in actual samples. Besides, a portable fluorescence detection platform was developed in combination with a smartphone color scanning APP to simplify the detection process and realize real-time semi-quantitative analysis.

Synergy of Post-Crosslinked imprinting strategy and silanol chemistry for the anisotropic construction of molecularly imprinted polymers onto Halloysite nanotubes

Searching for alternative porous substrates which can realize anisotropic preparation of “tailor-made” complementary binding sites is an important way to improve the identification efficiency and interfacial stability of the surface molecularly imprinted polymers (SMIPs). In this work, a functional polymer (FP) with multi-functional properties was firstly synthesized using 3-(isobutenyloxy) propyltrimethoxysilane, 1-(vinylbenzyl) thymidine and cinnamoyloxyethyl methacrylate (CEMA) as monomers, and then FP with post-crosslinking property was covalently deposited onto theoutersurfaceof halloysite nanotubes (HNTs) using silanol chemistry to prepare 2′-deoxyadenosine (dA) imprinted sorbents (HNTs-SMIPs). More than 65 % of dA molecules was captured within the first 2.0 h. The number of high affinity site from the total binding sites of HNTs-SMIPs is estimated to be as high as 73.25 %, and the maximum adsorption amount of HNTs-SMIPs is 48.78 μmol g -1 at 25 °C. The imprinting factor (IF) of HNTs-SMIPs towards dA is 1.89, and 79.49 % the adsorption capacity is remained after five adsorption–desorption cycles. In addition, 70.2 % of the dA from spiked human urine samples can be selectively extracted by HNTs-SMIPs. HNTs-SMIPs have excellent interfacial stability and strong affinity for the template molecule dA, and this work provides a new strategy for the specific separation and enrichment of dA.

Change in lumen pore structure of halloysite nanotube membrane coating under varying pressure, time and temperature

Change in lumen pore structure of halloysite nanotube membrane coating under varying pressure, time and temperature