Search Results (46)

Ice accumulation on aircraft surfaces severely affects aerodynamic performance by increasing drag and reducing lift, leading to stall conditions. Conventional thermal and pneumatic anti-/de-icing systems, although widely used, have some disadvantages, including high cost, inefficiency, and environmental unsustainability. Hydrophobic and icephobic coatings have emerged as a promising alternative to reduce ice adhesion and delay ice formation. This paper reviews the use of silane agents in epoxy-based coatings, incorporating functional additives such as natural fibers, quantum dots, and nanoparticles, to enhance hydrophobicity. Results demonstrated that the combination of silanes and functional additives affects surface features and wettability, improving hydrophobicity. These case studies show the potential of this approach in the development of coatings for advanced aircraft ice-protection applications. Full article

Developing an ultrasensitive electrochemiluminescence (ECL) detection platform remains challenging due to the limited enrichment efficiency of ECL emitters and co-reactants at the electrode interface, as well as the insufficient catalytic enhancement of co-reactant conversion. Moreover, simultaneous in situ analyte enrichment and efficient anti-interference capability are often difficult to achieve in a single sensing interface. Herein, a new ECL platform was developed based on nanocatalyst-supported nanochannel-confined surfactant micelle (SM) system, which integrates an enhanced luminol-dissolved oxygen (DO) ECL response for the ultrasensitive detection of antibiotic rifampicin (RIF). A nanocomposite comprising nitrogen-doped graphene quantum dots and a molybdenum disulfide nanosheet (NGQDs@MoS₂) was modified on an indium tin oxide (ITO) electrode. This nanocomposite layer catalyzed the oxygen reduction reaction (ORR), boosting the co-reactant efficiency of DO. Vertically ordered mesoporous silica film filled with surfactant micelles (SM@VMSF) was subsequently grown in situ on the NGQDs@MoS₂ surface. The hydrophobic micelles enable the simultaneous enrichment of luminol, DO, and RIF. Integrating the triple-enrichment effect of surfactant micelles with the high electrocatalytic effect of NGQDs@MoS₂ nanocomposite results in significant ECL enhancement of the luminol–DO. SM@VMSF also provides an excellent molecular sieving effect, endowing the sensor with high anti-interference capability and stability. RIF quenches the ECL signal by consuming superoxide anion radicals, enabling sensitive detection. Detection of RIF was established with a high sensitivity (2927 a.u. per nM) wide linear range (10 pM to 10 μM) and a low limit of detection (LOD, 2.5 pM). The fabricated sensor exhibits good selectivity and high fabrication reproducibility (relative standard deviation, RSD, of 1.9%). Additionally, the determination of RIF in eye drops and seawater samples was realized. This work offers new insights for the design of high-performance ECL sensing interfaces and sensitive detection of RIF. Full article

In this paper, to remove the water lock effect in tight gas reservoirs, amphipathic polymer-modified titanium quantum dots (PTQs) were synthesized via in situ polymerization, showing a hyper-branched structure and an excellent synergistic effect with the nonionic fluorocarbon surfactant to break the water lock. The molecular structure, fluorescent property, and micromorphology of the PTQs were obtained. The surface activity and wettability alteration of rock are discussed. Results show that PTQs have zwitterionic hydrophilic groups and the hydrophobic structure of long-chain groups on their molecular structure. PTQ fluid, with a median particle size of 3.6 nm, showed strong green fluorescence and had excellent dispersibility in 50,000 mg/L of standard saline fluid at 120 °C. Additionally, the surface tension decreased to 18.6 mN/m at a PTQ concentration of 0.08%. At a 0.1% concentration, PTQ fluid altered the water wettability of tight sandstone to 67.2°, which resulted in lower capillary resistance. Furthermore, the surfactant (PHPE) had a good synergistic effect with the PTQs to decrease surface tension and alter the wettability of the sandstone surface, leading to lower surface tension and significant amphiphobicity. The strong surface activity of PTQs results from their specific molecular structure, which enables electrostatic attraction, quantum size effects, hydrogen bonding, and van der Waals forces between the inter-polar molecules of PTQs and the surface of sandstone to forcefully eliminate the water lock effect. This study offers key guidance for the development of a high-performance water-lock-breaking agent and application of titanium quantum dots in tight gas reservoirs. Full article

Hydrophobic carbon quantum dots (hbCQDs) with tunable photoluminescence were synthesized via a solvothermal approach and further hybridized with Rhodamine B (RhB) to extend emission into the visible range. The hbCQDs exhibit quasi-spherical morphology with an average particle size of 8 nm and predominantly disordered graphitic structure, as confirmed by TEM and XRD analyses. FTIR and XPS characterizations reveal surface functional groups including C–N, C=O/C–O, and S–H, which govern the photoluminescence properties. Pure hbCQDs display blue emission at 453 nm under excitation, with a quantum yield (QY) of 6.2%. Incorporation of RhB leads to dual-emission behavior: the surface-state emission remains in the blue region, while molecular-state emission from RhB appears in the orange-red region. The 0.2 mL RhB–CQD composite exhibits optimal properties, including a QY of 13% and a production yield of 82%, emitting white light under 365 nm UV excitation. Increasing RhB loading to 0.4 mL results in a shift in emission peaks and a reduced QY (<9%), with weaker orange fluorescence. These findings demonstrate that controlled RhB hybridization effectively tunes the emission spectrum of hbCQDs, offering a simple and reproducible strategy to achieve dual-color and white-light emission. The optimized hbCQDs/RhB composites hold significant potential for applications in hydrophobic media-compatible organic optoelectronics, light-emitting devices, and bioimaging. Full article

Hydrophobicity has limited the efficiency of many drugs. To improve this, gold–silver alloy nanocomposites covered with carbon-based quantum dots were synthesized as a platform to reduce the drugs’ hydrophobicity. Using the hydrophobic drug Andrographolide as a model, it was demonstrated that these nanocomposites can decrease Andrographolide’s hydrophobicity (Log P from 2.632 to 0.56) without encapsulating the drug. Entry within prostate cancer (PC-3) cells and in vitro localization of the nanocomposites and Andrographolide was observed qualitatively via confocal microscopy and their identity confirmed by SERS inside the PC-3 cells. MTS assays demonstrated the carbon-based quantum dot layer covering the metal core of the nanocomposites stabilizes the oxidation rate of the nanocomposite’s core metals. This was observed by a decrease in cytotoxicity in PC-3 cells when compared to other gold or silver nanosystems for similar timeframes published in the literature. Full article

The rapid and selective discrimination of microplastics (MPs) is a critical analytical challenge, particularly as current carbon quantum dot (CQD)-based sensors often rely on single-wavelength “turn-on/off” or staining mechanisms that lack polymer-specific resolution. This work addresses these limitations by presenting a mechanism-driven fluorescence sensing platform using ultra-fine polyamide-derived carbon quantum dots (PACQDs; ~1.4 nm) to identify three prevalent MPs: polyamide (PA), polypropylene (PP), and polyethylene terephthalate (PET). Excitation–emission matrix (EEM) spectroscopy reveals polymer-specific photophysical responses: PAMPs and PPMPs induce fluorescence enhancement of 11.66% and 11.43%, respectively, whereas PETMPs cause net quenching (−4.61%) alongside a distinct, red-shifted emission band. Despite a common scatter-dominated peak at 290/308 nm, quantitative discrimination is achieved via integrated intensity and red/blue emission ratios (0.0137 for PAMPs, 0.0098 for PPMPs, and 0.0072 for PETMPs). Multivariate analysis reinforces this discrimination. Parallel factor analysis (PARAFAC) resolves the EEM data into three fluorescent components representing the intrinsic CQDs core and two interaction-induced surface states with a rank 3 model reducing the relative reconstruction error from 0.1625 to 0.1285. Principal component analysis (PCA) yields clear separation of the polymer classes, with the first two principal components capturing ~88% of the total spectral variance. ATR–FTIR spectroscopy provides direct molecular evidence for the underlying mechanisms: amide–amide coupling and interfacial rigidification for PAMPs; hydrophobic interaction without spectral shifts for PPMPs; and a synergistic interaction involving hydrogen bonding and π–π stacking for PETMPs. In particular, these polymer-specific fluorescence fingerprints are largely preserved in tap water, despite elevated background intensity and partial contrast attenuation, demonstrating the resilience of the EEM–chemometric approach under realistic matrix conditions. Collectively, the strong agreement between fluorescence metrics, multivariate signatures, and interfacial chemistry establishes a robust structure–property framework and positions PACQDs as a rapid, label-free, and matrix-tolerant platform for reliable microplastic discrimination in environmental analysis. Full article

CuO/TiO₂ is a highly active visible-light-driven photocatalyst. The precise structural regulation of TiO₂ and the quantum dot-scale loading strategy of CuO have long been researching hotspots and challenges. This work presents an ingenious synthetic strategy, leveraging the photoinduced superhydrophilicity and dark-induced reversible hydrophobicity of TiO₂, coupled with carbon quantum dots (CQDs) as “seeds” to induce the in situ synthesis of CuO quantum dots (CuO QDs). Specifically, CuO QDs with an average diameter of 5–10 nm were successfully anchored onto TiO₂ nanowire arrays (TNWAs) with a diameter of 10–15 nm. By adjusting the dosage of “seeds” (CQDs), the loading amount of CuO QDs can be effectively controlled. Corresponding characterizations were performed, including ultraviolet-visible-near-infrared (UV-Vis-NIR spectroscopy) for optical absorption properties, photoluminescence (PL) spectroscopy for photoluminescent behavior, electron paramagnetic resonance (EPR) spectroscopy for free radical generation capability, and bisphenol A (BPA) degradation assays for photocatalytic performance. Loading 4.78 wt% CuO QDs can effectively inhibit the recombination of electron–hole pairs in TNWAs. Simultaneously, it prolongs the lifetime of charge carriers (photoelectrons) and enhances the yields of hydroxyl radicals (•OH) and superoxide radicals (•O₂⁻). The BPA degradation efficiency of the CuO QDs/TNWA composite is 2.4 times higher than that of TNWAs. Furthermore, we found that the loading of CuO QDs significantly modulates the depletion layer width of the P–N heterojunction, and the underlying mechanism has been discussed in detail. Full article

The hybrid inorganic–organic material concept plays a bold role in multifunctional materials, combining different features on one platform. Once varying properties coexist without cancelling each other on one matrix, a new type of supermaterial can be formed. This concept showed that silver nanoparticles can be embedded together with inorganic and organic surface coatings and silicon quantum dots for symbiotic antibacterial character and UV-excited visible light fluorescent features. Additionally, fluorosilane material can be coupled with this prepolymeric structure to add the hydrophobic feature, showing water contact angles around 120°, providing self-cleaning features. Optical properties of the components and the final material were investigated by UV-Vis spectroscopy and PL analysis. Atomic investigations and structural variations were detected by XPS, SEM, and EDX atomic mapping methods, correcting the atomic entities inside the coating. FT-IR tracked surface features, and statistical analysis of the quantum dots and nanoparticles was conducted. Multifunctional final materials showed antibacterial properties against E. coli and S. aureus, exhibiting self-cleaning features with high surface contact angles and visible light fluorescence due to the silicon quantum dot incorporation into the sol-gel-produced nanocomposite hybrid structure. Full article

The tear film, consisting of the aqueous and lipid layers, maintains the homeostasis of the ocular surface; therefore, when disturbed, it can cause dry eye, which affects millions of people worldwide. Understanding the dynamics of the tear film layers is essential for developing efficient drug delivery systems for dry eye disease. Quantum dots (QDs) offer the potential for real-time monitoring of tear film and evaluating its dynamics. Hydrophilic silicon QDs (Si-QDs) have already been optimised to image the aqueous layer of the tear film. This study was conducted to optimise hydrophobic Si-QDs to image the lipid layer of the tear film. Si-QDs were synthesised in solution and characterised by transmission electron microscope and spectrofluorophotometry. The fluorescence emission of Si-QDs was monitored in vitro when mixed with artificial tears. The cytotoxicity was assessed in cultured human corneal epithelial cells using an MTT assay following 24 h of exposure. Si-QDs were 2.65 ± 0.35 nm in size and were non-toxic at <16 µg/mL. Si-QDs emitted stable green fluorescence for 20 min but demonstrated aggregation at higher concentrations. These findings highlight the potential of hydrophobic Si-QDs as a biomarker for the real-time imaging of the tear film lipid layer. However, further research on surface functionalisation and preclinical evaluations are recommended for enhanced solubility and biocompatibility in the ocular surface. Full article

This study aims to optimize the demulsification performance of a carbon quantum dot (CQD)-enhanced chemical demulsifier in industrial emulsions under thermal, mechanical, and thermomechanical effects. Experiments were conducted to assess treatments like organic treatment (OT), zeta potential modifier aqueous solution (ZPMAS), and acid treatment (9.25 wt.% HCl) at varying dosages, along with CQD–chemical mixtures optimized through a simplex-centroid mixture design (SCMD) to minimize basic sediment and water (BSW). Under the thermomechanical scenario, a system with 500 mg∙L⁻¹ CQDs and OT achieves 0.5% BSW and a droplet size of 63 nm, while an SCMD-optimized system (500 mg∙L⁻¹ CQDs + 380 mg∙L⁻¹ OT + 120 mg∙L⁻¹ ZPMAS) achieves 0% BSW and larger droplets (>70 nm). CQDs enhance demulsifiers by destabilizing water-in-oil (W/O) Pickering emulsions, leveraging their nanometric size, high surface area, thermal conductivity, and amphiphilicity, thanks to their hydrophobic core and surface hydrophilic groups (-OH, NH₂, -COOH). This research enhances the understanding of demulsification by employing green demulsifiers based on CQDs and provides a promising cost-efficient solution for breaking stable emulsions in the petroleum industry. It minimizes the use of complex and expensive active ingredients, achieving BSW values below 0.5%, the standard required for crude oil transport and sale, while also reducing separation equipment operation times, and improving overall process efficiency. Full article

CsPbIBr₂, with its suitable bandgap, shows great potential as the top cell in tandem solar cells. Nonetheless, its further development is hindered by a high defect density, severe carrier recombination, and poor stability. In this study, CsPbI_1.5Br_1.5 quantum dots were utilized as an additive in the ethyl acetate anti-solvent, while a layer of CsPbBr₃ QDs was introduced between the ETL and the CsPbIBr₂ light-harvester film. The combined effect of these two QDs enhanced the nucleation, crystallization, and growth of CsPbIBr₂ perovskite, yielding high-quality films characterized by an enlarged crystal size, reduced grain boundaries, and smooth surfaces. And a wider absorption range and better energy band alignment were achieved owing to the nano-size effect of QDs. These improvements led to a decreased defect density and the suppression of non-radiative recombination. Additionally, the presence of long-chain organic molecules in the QD solution promoted the formation of a hydrophobic surface, significantly enhancing the long-term stability of CsPbIBr₂ PSCs. Consequently, the devices achieved a PCE of 9.20% and maintained an initial efficiency of 85% after 60 days of storage in air. Thus, this strategy proves to be an effective approach for the preparation of efficient and stable CsPbIBr₂ PSCs. Full article

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. Full article

Dopamine (DA) is a widely present, calcium cholinergic neurotransmitter in the body, playing important roles in the central nervous system and cardiovascular system. Developing fast and sensitive DA detection methods is of great significance. Fluorescence-based methods have attracted much attention due to their advantages of easy operation, a fast response speed, and high sensitivity. This study prepared hydrophilic and high-performance CdS/ZnS quantum dots (QDs) for DA detection. The waterborne CdS/ZnS QDs were synthesized in one step using the amphiphilic polymer PEI-g-C14, obtained by grafting tetradecane (C14) to polyethyleneimine (PEI), as a template. The polyacrylonitrile nanofiber membrane (PAN-NFM) was prepared by electrospinning (e-spinning), and a metal organic frame (ZIF-8) was deposited in situ on the surface of the PAN-NFM. The CdS/ZnS QDs were loaded onto this substrate (ZIF-8@PAN-NFM). The results showed that after the deposition of ZIF-8, the water contact angle of the hydrophobic PAN-NFM decreased to within 40°. The nanofiber membrane loaded with QDs also exhibited significant changes in fluorescence in the presence of DA at different concentrations, which could be applied as a fast detection method of DA with high sensitivity. Meanwhile, the fluorescence on this PAN-NFM could be visually observed as it transitioned from a blue-green color to colorless, making it suitable for the real-time detection of DA. Full article

Polyvinyl alcohol (PVA) is a popular material used in the packaging industry. However, it is vulnerable to moisture, which can affect its performance and durability. Introducing hydrophobic substances, such as tetraethyl orthosilicate (TEOS) and hexadecyltrimethoxysilane (HDTMS), on the top layer of PVA can help maintain the excellent properties of PVA under high-humidity conditions. The low compatibility of hydrophobic materials with the hydrophilic layers allows them to aggregate more easily. To overcome these issues, we focused on the effects of particle size when increasing the coating suspension’s dispersibility. A carbon quantum dot (CQD) suspension is an appropriate novel solvent for hydrophobic TEOS/HDTMS coating suspensions because its particles are small and light and exhibit good dispersibility. The CQD suspension formed a smooth hydrophobic coating on the TEOS/HDTMS materials. Furthermore, the uniformly coated PVA with the CQD suspension exhibited a water contact angle of 110°. The water droplets remained intact without being absorbed, confirming the effectiveness of the surface coating facilitated by CQDs. These results suggested that CQDs improved the dispersibility and enhanced the coating quality of TEOS/HDTMS on PVA. Enhancing the hydrophobicity of PVA is ideal for applications in packaging and other fields. Full article

Fluorescent carbon dots (CDs) are a new type of photoluminescent nanomaterial. Solid-state CDs usually undergo fluorescence quenching due to direct π-π* interactions and superabundant energy resonance transfer. Therefore, the preparation of solid-state fluorescent CDs is a challenge, especially the preparation of long wavelength solid-state CDs. In this research, long wavelength emission CDs were successfully synthesized by solvothermal methods, and the prepared CDs showed good hydrophobicity. The composite solid-state CDs/PVP (Polyvinyl pyrrolidone) can emit strong red fluorescence, and the quantum yield (QY) of the CDs/PVP powder reaches 18.9%. The prepared CDs/PVP solid-state powder was successfully applied to latent fingerprint detection. The results indicate that the latent fingerprints developed by CDs/PVP powder have a fine definition and high contrast visualization effect, which proves that the prepared CDs/PVP has great application potential in latent fingerprint detection. This study may provide inspiration and ideas for the design of new hydrophobic CDs. Full article