Langmuir最新文献

Gaining in-depth insights into the adsorption mechanism of collectors serves as the core scientific basis for achieving efficient spodumene (the most important lithium-bearing mineral) flotation. Due to the spodumene exhibits complex anisotropic surface properties, the quantitative understanding of the facet-dependent interaction between collectors and spodumene surfaces remains challenging. Herein, taking the typical collectors sodium oleate (NaOL) and dodecylamine (DDA) used in spodumene flotation separation, the chemical force microscopy technique was used to quantitatively measure the intermolecular interactions between collectors and different spodumene surfaces (110, 100, and 010) at the nanoscale. Adhesion measurements revealed that the adhesion forces of DDA with the (110), (100), and (010) surfaces were 21.7, 43.3, and 23.3 mN/m, respectively, with adhesion energies following the order (100) > (010) ≈ (110). Anisotropic adhesion was attributed to variations in the density of negatively charged O atoms on the surfaces. Conversely, the strong electrostatic repulsion between -COO- group and spodumene surfaces induced much weaker adhesion (1.7-8.8 mN/m) of NaOL toward all the surfaces. The adhesion energies between oleate ions and spodumene surfaces followed the order (110) ≈ (010) > (100), which correlated with differences in the number of exposed Al sites on the surfaces. Furthermore, the stronger adhesion between -NH₃⁺ group and spodumene surfaces enabled DDA to adsorb more stably and effectively onto them, thereby enhancing the surface hydrophobicity and facilitating spodumene flotation. This study provides quantitative insights into the facet-dependent adsorption of collectors on mineral surfaces at the nanoscale, offering significant potential for establishing a quantitative link between mineral flotation behavior and the interaction forces between collector molecules and mineral surfaces.

Spatially periodic patterns have been widely studied in chemical and biological systems, yet the emergence of hierarchical or multiscale architectures remains less explored experimentally, particularly in minimal material frameworks. In this work, it was observed in real time that a simple two-component solution consisting of methyltrimethoxysilane and phytic acid spontaneously forms macroscale hierarchical patterns upon exposure to air. Spectroscopic analyses reveal that chemical reactions initiated by environmental moisture drive sol-gel condensation and reaction-induced phase separation (RIPS), leading to the development of compositionally distinct microdomains. The resulting solid structures exhibit both periodic macroscopic wrinkle patterns and microscale anisotropic textures. The correlation between wrinkle spacing and film thickness suggests mechanical stress relaxation (buckling) during solidification, while the presence of localized contour-like features indicates anisotropic molecular ordering within the segregated domains. These findings show that hierarchical pattern formation can arise from the coupled effects of chemical reaction, phase separation, mechanical confinement, and molecular ordering in a minimal system. This platform provides an experimentally accessible route to study pattern formation mechanisms and may offer a basis for designing self-organized materials with multiscale architectures.

Zwitterionic polymers are widely recognized for their exceptional antifouling performance; however, integrating zwitterionic functionality into polyurethane while retaining mechanical robustness and processability remains a significant challenge. Addressing this gap, we introduce a versatile design strategy for synthesizing zwitterionic polyurethanes that integrate both zwitterionic diol and triol precursors, enabling long-term antifouling performance and tunable physical properties. We report the synthesis of a new class of poly(carboxybetaine hexamethylene urethane) (PCBHU) prepared through step-growth polymerization of carboxybetaine (CB)-based diols/triols and aliphatic diisocyanates, followed by controlled ester hydrolysis to generate zwitterionic groups along the polymer backbone. The formation of densely hydrated CB moieties establishes a strongly bound hydration layer that governs the antifouling behavior. The resulting materials exhibit excellent thermal stability, with degradation temperatures above 200 °C, and well-defined thermal transitions characterized by TGA and DSC. By varying the soft-to-hard-segment ratio, we achieved precise control over mechanical properties and water uptake, revealing clear structure-property relationships within this zwitterionic PU platform. Importantly, the PCBHUs markedly suppress nonspecific protein adsorption, mammalian cell adhesion, bacterial attachment, and biofilm formation, demonstrating durable antifouling performance far superior to conventional polyurethanes. The synthesis route is simple, scalable, and compatible with existing PU manufacturing, enabling these PCBHUs to serve as drop-in replacements for commercial polyurethane lacking antifouling functionality. This strategy provides a practical and broadly applicable approach for endowing polyurethane-based biomaterials and medical devices with long-lasting antifouling properties.

Band gap engineering is an intricate aspect in the domain of photocatalysis which vastly impacts the performance of catalysts. This study demonstrates how solvents can be incorporated in photocatalytic schemes to play the role of functionally active components to enhance the performance. Herein, a series of DESs with different metallic entities (Zn, Cu, Ni and Ce) were designed and strategically hybridized with a model photocatalyst, g-C₃N₄. The g-C₃N₄/Zn system showed the best structural and morphological traits compared to other developed systems, which rendered it with the best photocatalytic attributes. It exhibited the best photocatalytic performance toward both the model pollutants, tetracycline hydrochloride (TC) and methylene blue (MB). Precisely, activity enhancement of 30% and 33% was obtained with the g-C₃N₄/Zn system for MB and TC compared to unmodified g-C₃N₄. The electronic structure investigation of the developed catalytic systems pointed toward an intricate coordination. For instance, in the best performing g-C₃N₄/Zn system, a Z-scheme type mechanism was deduced between DES and the g-C₃N₄. Based on the investigations, a plausible mechanism has been proposed to holistically explain the role of DESs in enhancing the photocatalytic performance of the system.