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•Self-healing performance of epoxy-based double-layer coatings are reported.•The epoxy matrix is reinforced with modified zirconia (ZrO2) nanoparticles.•ZrO2 nanoparticles are ...modified with Imidazole and PEI as the self-healing agent.•Epoxy-based nanocomposite coatings are deposited as pre and topcoat on substrate.•EIS results demonstrated good corrosion resistance of double-layer coatings.
This work reports the self-healing behavior of epoxy-based double-layer nanocomposite coatings designed to mitigate corrosion in various industrial applications. Zirconia (ZrO2) nanoparticles were used as a carrier to load separately self-healing agent, polyethyleneimine (PEI), and corrosion inhibitor, imidazole (IM). The loaded ZrO2 nanoparticles with IM and PEI were doped into the epoxy matrix and applied on polished steel substrate to form pre and top layers of nanocomposite coatings, respectively. TEM analysis confirms the almost globular morphology of the zirconia nanoparticles with a particle size of 15–25 nm. The chemical bonding interactions among various species were confirmed through FTIR. The synergistic effect of self-healing agent and corrosion inhibitor in epoxy-based double-layer nanocomposite coatings demonstrated the pH and time dependence release of inhibitor and self-healing agent. A comparative EIS analysis conducted in 3.5 wt% NaCl solution reveals that epoxy-based double-layer nanocomposite coatings demonstrate improved corrosion resistance performance as compared to the blank epoxy and single layer epoxy reinforced coatings. This enhanced corrosion resistance of epoxy-based double-layer nanocomposite coatings can be ascribed to the efficient release of loaded IM and PEI in response to the external stimuli and can be potentially considered to circumvent corrosion in oil & gas and marine applications.
Novel hybrid halloysite nanotubes (HHNTs) were developed and used as smart carriers for corrosion protection of steel. For this purpose, as-received halloysite nanotubes (HNTs) were loaded with a ...corrosion inhibitor, imidazole (IM), by vacuum encapsulation. In the next step, a layer by layer technique was employed to intercalate another inhibitor, dodecylamine (DDA), in the polyelectrolyte multilayers of polyethylenimine and sulfonated polyether ether ketone, leading to the formation of HHNTs. During this process, IM (5 wt %) was successfully encapsulated into the lumen of HNTs, while DDA (0.4 wt %) was effectively intercalated into the polyelectrolyte layers. Later, the HHNTs (3 wt %) were thoroughly dispersed into the epoxy matrix to develop smart hybrid self-healing polymeric coatings designated as hybrid coatings. For a precise evaluation, epoxy coatings containing as-received HNTs (3 wt %) without any loading denoted to as reference coatings and modified coatings containing HNTs loaded with IM-loaded HNTs (3 wt %) were also developed. A comparative analysis elucidates that the hybrid coatings demonstrate decent thermal stability, improved mechanical properties, and promising anticorrosion properties compared to the reference and modified coatings. The calculated corrosion inhibition efficiencies of the modified and hybrid coatings are 92 and 99.8%, respectively, when compared to the reference coatings. Noticeably, the superior anticorrosion properties of hybrid coatings can be attributed to the synergetic effect of both the inhibitors loaded into HHNTs and their efficient release in response to the localized pH change of the corrosive medium. Moreover, IM shows an active release in both acidic and basic media, which makes it suitable for the protection of steel at the early stages of damage, while DDA being efficiently released in the acidic medium may contribute to impeding the corrosion activity at the later stages of deterioration. The tempting properties of hybrid coatings demonstrate the beneficial role of the development of novel HHNTs and their use as smart carriers in the polymeric matrix for corrosion protection of steel.
Smart polymeric composite coatings demonstrating multilevel self-healing characteristics were developed and characterized. The pH-responsive smart carriers were synthesized by loading halloysite ...nanotubes (HNTs) with the benzotriazole corrosion inhibitor (BTA) using the vacuum cycling method, referred to as (BTA-loaded HNTs). Similarly, mechanically triggered melamine urea-formaldehyde microcapsules encapsulated with the boiled linseed oil-self-healing agent (LO) denoted as (MUFMCs) having an average size of a ∼120 μm diameter with a wall thickness of ∼1.84 μm were synthesized by the in situ polymerization technique. The newly designed double-layered smart polymeric composite coatings (DLPCs) were developed by mixing 3 wt % BTA-loaded HNTs with epoxy and applying it on the clean steel substrate to form a primer layer. After its complete curing, a top layer of epoxy containing 5 wt % of MUFMCs was deposited on it. For an exact comparison, single-layer polymeric composite coatings (SLPCs) containing 3 wt % BTA-loaded HNTs were also developed. The Fourier transform infrared radiation spectra of MUFMCs and BTA-loaded HNTs indicate the existence of all desired functional groups, confirming the presence of loaded chemical species such as LO and BTA into the smart carriers. Thermogravimetric analysis (TGA) indicates that ∼18% BTA is successfully loaded into HNTs. Quantitative UV-spectroscopic analysis indicates a pH-responsive release of BTA from BTA-loaded HNTs, which is time-dependent, attaining its maximum value of ∼ 90% in an acidic medium after 30 h. Electrochemical impedance spectroscopy analysis conducted in 3.5 wt % NaCl solution at room temperature for different immersion times reveals that SLPC exhibits the maximum charge-transfer resistance (R ct) of 55.47 GΩ cm2 after the 7th day of immersion, and then, a declining trend is observed, reaching 26.6 GΩ cm2 after the 9th day. However, in the case of DLPC, the R ct values show a continuous increment, attaining a maximum value of 82.11 GΩ cm2 after the 9th day of immersion. The improved performance of DLPC can be ascribed to the efficient triggering of the individual carriers in the isolated matrices, resulting in the release of LO and BTA to form individual protective films at the damaged area due to the oxidative polymerization process and triazoles’ ability of passive film formation on the substrate, respectively. The tempting self-healing properties of DLPCs justify their decent role for long-term corrosion protection in many industrial applications.
Forward osmosis is considered as the least energy intensive membrane process since it operates based on the osmotic pressure gradient. However, it is still considered as immature technology mainly ...due to the elevated cost for draw solution regeneration. Nevertheless, magnetic nanoparticles could be considered as a sustainable draw solute for forward osmosis due to high osmotic pressure and easy regeneration using magnetic force, but a significant development is still needed before implementing it for wastewater treatment and desalination. Herein, we analyzed the performance of the available magnetic nanoparticles draw solute and identified the challenges facing the use of magnetic nanoparticles as draw solute in the forward osmosis process. We first highlight the common synthesis methods of magnetic nanoparticles, and basics for generation of osmotic pressure using magnetic nanoparticles. Then, we analyzed the performance and limitations of available magnetic nanoparticles that were used as draw solute in the forward osmosis process. Later, we assessed the toxicity level of the magnetic nanoparticles and explored the regulations of using magnetic nanoparticles in the water treatment industry. Finally, new avenues of research were proposed to make magnetic nanoparticles draw solution more effective when applying it in desalination and wastewater treatment process.
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•Magnetic nanoparticle is a promising draw solute for forward osmosis.•The impact of magnetic nanoparticles coating type on water flux was analyzed.•The toxicity of the MNPs and limitations of existing water treatment standards.•State-of-the-art MNPs draw solute were assessed with suggestions for future research.
Forward osmosis is the least energy intensive water treatment membrane process, however, designing a sustainable draw solute is still a critical research necessity. In this work, we developed ...Poly(amidoamine) dendrimer coated magnetic nanoparticles (PAMAM-MNPs) to be used as a draw solute in the forward osmosis process. Poly(amidoamine) dendrimer was selected due to its highly branched tree-like structure, diverse types of terminal groups, and ability to induce high osmotic pressure. The synthesized MNPs had a crystalline structure of a single-phase magnetite, spherical shape with an average size of 11.8 nm for bare MNPs, and 17.1 nm for PAMAM-MNPs. The performance of the synthesized MNPs as draw solute was tested using a bench scale forward osmosis setup. The average water flux obtained was 12.9 LMH during the first running cycle and decreased with time due to the dilution of draw solution. The MNPs were easily recovered using a permanent magnet and reused as draw solute for multiple cycles. The average water decreased by almost 25 % after four running cycles due to membrane fouling. This study highlighted the performance and limitations of using a newly developed dendrimer coated MNPs draw solute in the forward osmosis process.
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•Poly(amidoamine) dendrimer coated magnetic nanoparticles was used as draw solute.•Poly(amidoamine) dendrimer has a highly branched tree-like structure.•The average water flux obtained was 12.9 LMH during the first cycle.•A full recovery of the magnetic nanoparticles was achieved using permanent magnet.•Membrane fouling when using magnetic nanoparticles as draw solute was evaluated.
Iron oxide magnetic nanoparticles (MNPs) are crucial in various areas due to their unique magnetic properties. However, their practical use is often limited by instability and aggregation in aqueous ...solutions. This review explores the advanced technique of dendrimer functionalization to enhance MNP stability and expand their application potential. Dendrimers, with their symmetric and highly branched structure, effectively stabilize MNPs and provide tailored functional sites for specific applications. We summarize key synthetic modifications, focusing on the impacts of dendrimer size, surface chemistry, and the balance of chemical (
e.g.
, coordination, anchoring) and physical (
e.g.
, electrostatic, hydrophobic) interactions on nanocomposite properties. Current challenges such as dendrimer toxicity, control over dendrimer distribution on MNPs, and the need for biocompatibility are discussed, alongside potential solutions involving advanced characterization techniques. This review highlights significant opportunities in environmental, biomedical, and water treatment applications, stressing the necessity for ongoing research to fully leverage dendrimer-functionalized MNPs. Insights offered here aim to guide further development and application of these promising nanocomposites.
The various functionalization and conjugation mechanisms of dendrimers with magnetic nanoparticles (MPNs).
This study aimed to evaluate the effectiveness of DentalVibe in pain reduction during local anesthetic injection compared to traditional injection in pediatric patients.
This cross-over randomized ...controlled clinical trial included a sample of 60 children, aged 5 to 7 years, who were selected based on the need for local anesthesia for bilateral mandibular pulpotomy treatment. They were randomly allocated into two groups. Each group received two mandibular nerve block injections, with a 2-week interval as the washing out period. At first appointment, mandibular nerve block injection was performed either with vibration using DentalVibe at the injection site or benzocaine gel 20% applied before local anesthetic injection; the alternative technique was used at the second appointment. In each visit subjective pain was evaluated using the Wong-Baker FACES Pain Rating Scale and objective pain was evaluated using the FLACC (Face, Legs, Activity, Cry, Consolability) scale.
Assessment using the Wong-Baker FACES Pain Rating Scale showed that the mean pain levels in DentalVibe and traditional injection groups were 0.80 ± 1.34 and 2.60 ± 3.22, respectively. The mean pain levels according to the FLACC scale were 2.20 ± 2.04 and 3.13 ± 2.30 in the DentalVibe and traditional injection groups, respectively. Both scales showed statistically significant differences between the two groups in favor of DentalVibe (P < .001). A positive significant correlation between the two scales in the two interventions was recorded, where the Spearman rho was 0.41 for the DentalVibe group, and 0.52 for traditional injection group (P < .001).
Compared to the traditional approach, DentalVibe reduced pain sensation during mandibular nerve block injection in pediatric patients.
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