Langmuir最新文献

As a novel phenomenon recently unveiled in immersion lithography research, bubble-encapsulated droplets vanish in mere fractions of a second. Despite their subsecond lifetimes, bubble-encapsulated droplets hold significant potential for applications including cell incubation, droplet microreactors, and in situ sampling in environmental fluids. Here, we couple patterned superhydrophobic surfaces (PSHSs) with laser-induced cavitation to achieve controllable droplet encapsulation inside a surface-attached bubble. High-speed shadowgraphy shows that collapse near an attached bubble generates a microjet directed toward the PSHS. With the dimensionless separation distance γ and radius ratio ε scaled by the maximum cavitation bubble radius (R_max), the internal jet transitions between conical, concave, and crown-like morphologies. During jet impaction, the liquid thread undergoes necking and pinch-off under the coupled action of inertia, surface tension, and gravity, producing droplets that remain confined within the surface-attached bubble for days. At fixed ε, the microjet velocity decreases with increasing γ, whereas the encapsulated droplet radius R_d varies nonmonotonically with γ. At fixed γ, R_d increases with ε, while the dimensionless encapsulation time τ_d decreases with ε. These results establish a repeatable, noncontact route to long-lived bubble-encapsulated droplets and quantitatively demonstrate the tunability of this encapsulation technique while deepening mechanistic insights into its encapsulation formation dynamics.

The development of intelligent nanocarriers capable of overcoming the intrinsic limitations of conventional pesticides, including poor foliar adhesion, photodegradation, and nonspecific release, remains a major challenge in agrochemical science. Herein, we report a multifunctional core-shell nanocarrier (Pro@ZnO@PDA, denoted as PZP NPs) constructed via interfacial engineering, in which prochloraz-loaded ZnO nanoparticles (ZnO NPs) are encapsulated within a polydopamine (PDA) shell. The rough surface of the ZnO core enables a high pesticide loading capacity of 12%, while the PDA shell markedly enhances leaf adhesion, reducing the contact angle on plant leaves by 25.4%, thereby improving foliar retention. Benefiting from acid-sensitive interfacial dissociation between the PDA shell and ZnO core, the nanocarrier exhibits pH-responsive release behavior, achieving a targeted prochloraz release of 76% under acidic conditions (pH 5.4). In addition, the ZnO core effectively shields the active ingredient from ultraviolet irradiation, resulting in a 23.3-fold enhancement in photostability, whereas the PDA shell provides efficient photothermal conversion, inducing an elevation of temperature up to 38.8 °C under light exposure. The integration of controlled chemical release and photothermal effects gives rise to a synergistic antifungal mechanism, maintaining an inhibition rate exceeding 60% after 7 days of irradiation. Notably, PZP NPs exhibit bidirectional translocation within plants, addressing the limited systemic transport of conventional fungicides. This work demonstrates an interfacial-engineered, stimulus-responsive nanoplatform that offers a promising strategy for intelligent and efficient pesticide delivery.

Rice husk-derived silica nanoparticles (RSN-50) possess an inherently negative surface charge over a wide pH range, which limits their effectiveness for the removal of chemically diverse pollutants. To overcome this dominant charge limitation, an amphoteric polyelectrolyte scaffold (ACS-4B) composed of chitosan (CS), alginate (Alg), and biosilica was designed to enable pH-responsive surface charge regulation using complementary functional groups (-COOH, -NH₃⁺, and -SiOH). ACS-4B demonstrated efficient adsorption of cationic dye (methylene blue, MB), anionic dye (Congo red, CR), and toxic metal ions (Pb²⁺ and Cr⁶⁺) across a wide pH range without pH adjustment. Mesoporous ACS-4B scaffolds with a specific surface area (233.2 m²/g) could achieve maximum adsorption capacity for MB (630 mg/g), CR (387 mg/g), Pb²⁺ (539 mg/g), and Cr⁶⁺ (585 mg/g) within 150 min at the inherent solution pH, indicating the pH-responsive amphoteric behavior of ACS-4B (CR (6.7), MB (5.9), Pb²⁺ (2.9), and Cr⁶⁺ (4.9)). The selective adsorption trends under mixed-pollutant conditions further reflect charge-adaptive interactions. ACS-4B retained its adsorption functionality over four consecutive regeneration cycles, indicating preliminary reusability. The combined amphoteric surface chemistry, inherent postadsorption pH-buffering ability, and biowaste-derived design highlight ACS-4B as a promising adsorbent for textile dye and metal-containing wastewater treatment.

This study demonstrates that a particle-mixing strategy in aqueous suspension is more effective than chemical dispersants in enhancing the dynamic dispersion and performance of SiO₂-based slurries for planarization applications. By preparing particle-mixed suspensions containing 25 and 55 nm SiO₂ particles at chemical-mechanical planarization (CMP)-relevant solid loadings (1-10 wt %), we show that combining these two particle sizes suppresses agglomeration and transforms the suspension rheology from shear-thinning to a nearly Newtonian response under flow, indicating improved dynamic dispersion after yielding. Small-angle X-ray scattering and effective volume packing analyses confirm that cooperative size effects drive the improved structural organization, thereby enhancing flow behavior. In contrast, the commonly used ammonium polyacrylate dispersant enhances static dispersion but fails to produce uniform flow behavior under shear. In CMP tests, suspensions with a bimodal particle size distribution achieve higher material removal rates and lower surface roughness than monodisperse or dispersant-stabilized suspensions simultaneously. Numerical simulations that couple the discrete element method and computational fluid dynamics further show that the improved CMP performance, resulting from the use of the powder-mixing suspension, is due to denser particle contacts and higher localized stresses in the bimodal system.

Immobilization of large biomacromolecules is often required for analytical quantification and physicochemical characterization. However, immobilization can alter the structure and size of the particles being studied. Here, two exosomes (derived from HEK-293 and MDA-MB-231 cells) and three viral particles (Suid herpesvirus 1 (SuHV), xenotropic murine leukemia virus (XmuLV), and porcine parvovirus (PPV)) were immobilized to different covalent chemistries to understand how surface chemistry influences particle deformation during immobilization. The surface chemistries explored were: (i) NHS (N-hydroxysulfosuccinimide) and EDC (1-ethyl-3-(3-(dimethylamino)propyl) carbodiimide hydrochloride), and (ii) poly l-lysine (PLL) and glutaraldehyde (GA). Morphological changes in biomolecules following immobilization were quantified by measuring the height-to-diameter (H/D) ratios attained from atomic force microscopy (AFM) topographic images. These observations were further supported by complementary size and morphology analyses using dynamic light scattering (DLS) and liquid phase transmission electron microscopy (TEM). NHS/EDC chemistry consistently resulted in more significant particle flattening than PLL/GA, as evidenced by lower average H/D ratios across all biomacromolecules. Greater flattening effects were observed on the soft lipid envelope of exosomes as compared to viruses, due to differences in structural rigidity. Both immobilization chemistries resulted in a lower H/D ratio in tumor-derived MDA-MB-231 exosomes compared to nontumor-derived HEK-293 exosomes, likely due to the known softer mechanical properties of tumor-derived exosomes. Furthermore, immobilization of the enveloped viruses SuHV and XMuLV with NHS/EDC exhibited flattening effects and lower H/D ratios. Immobilization of nonenveloped PPV resulted in a low H/D ratio on NHS/EDC, which was likely due to particle aggregation rather than deformation. These findings provide valuable guidance for selecting appropriate surface chemistries for nanoscale biointerface studies and offer implications for surface-based diagnostics, high-throughput biosensing, and nanomaterial functionalization.