ACS Applied Materials & Interfaces最新文献

Carbon black (CB) and silica are the most widely used reinforcing fillers for rubber composites. However, their molecular-scale surface differences and quantitative effects on interfacial interactions remain unclear, hindering the rational design of high-performance materials. In this study, CB- and silica-filled composites with equivalent interfacial areas were prepared to experimentally compare their interfacial interaction strengths. Molecular dynamics simulations using trans-3-hexene as probe molecules subsequently quantified the interaction strengths of CB and silica, showing good agreement with the experiments. Further analyses of surface energy distribution and the dependence of binding energy on adsorption distance revealed that the molecular-scale surface characteristics differ in three key aspects: adsorption energy, energy heterogeneity, and binding energy-distance correlation, thereby accounting for the inferior performance of silica-NR interfaces despite the presence of covalent bonding. On the basis of the simulation results, experiments under equivalent interfacial adsorption energies confirmed that interfacial physical adsorption dominates the overall interfacial interactions and validated the critical role of specific strong binding sites. In this study, an efficient molecular simulation methodology was established to overcome experimental limitations, and by integrating simulations with experiments, the influence of filler surface characteristics on interfacial interactions was elucidated, providing guidance for rational composite design.

Coke deposition is a key obstructive problem to be solved in the production of ethylene via steam cracking; moreover, the removal of graphitic carbon in coke is particularly difficult. A strategy integrating Fe-Mn bimetallic synergy at the B-site with oxygen vacancy engineering in perovskites was proposed to accelerate the catalytic conversion of coke/graphitic carbon via steam. DFT simulations and experimental results revealed that Mn incorporation induces dynamic lattice reconstruction of SrFeO₃, generating abundant oxygen vacancies that enhance oxygen ion mobility and H₂O adsorption. The interaction between Fe and Mn atoms has been observed to narrow the band gap, strengthen the hybridization of the O-2p and Fe-3d orbitals, induce electron delocalization, regulate the transfer of electrons from surrounding atoms to the adsorbed oxygen species, and thus accelerate the desorption and activation of *OH and the transfer of *O^2-, which provides the possible reaction pathway for the transformation of graphitic carbon into CO or CO₂. At 900 °C, the conversion of graphitic carbon and coke with steam catalyzed by SrFe_0.1Mn_0.9O₃ reached 60.61% and 99.87%, respectively. This study provides an active material that facilitates the in situ online decoking strategy for catalytic coatings on steam cracking furnace tubes along with theoretical insights into the underlying reaction mechanism.

Antibacterial nanocarrier-based anticancer drug delivery systems have garnered significant attention in the treatment of bacteria-associated cancers. By employing natural polyphenols in a green synthesis process, the inert surface of conventional silver nanoparticles (AgNPs) can be modified to enable anticancer drug loading and provide dual antibacterial and anticancer functionalities. However, the development of AgNPs with intrinsic antibacterial and antitumor activities for anticancer drug loading and bacteria-associated tumor combination therapy has not been extensively explored. Here, the extract of Rheum tanguticum Maxim. ex Balf. (RHT), an important traditional Chinese medicine, was utilized as a reducing and stabilizing agent for the green synthesis of AgNPs (RHT-AgNPs). The resultant RHT-AgNPs had spherical morphology, good dispersion, uniform particle size (15.14 ± 0.73 nm), and remarkable long-term stability in aqueous solutions (>43 days). Mass spectra (MS) and high-performance liquid chromatography (HPLC) analysis were performed to identify the main constituents in rhubarb extract responsible for the preparation of RHT-AgNPs. The resultant RHT-AgNPs (500 μg/mL) exhibited low long-term (72 h) cytotoxicity against normal cells (cell viability >54%) and retained significant antibacterial activity against both Escherichia coli and Staphylococcus aureus. More importantly, the RHT-AgNPs exhibited significant cytotoxic activity against breast cancer cells (IC₅₀ = 77.92 μg/mL), which originated from the rhubarb extract (IC₅₀ = 20.36 μg/mL), thus enabling an enhanced antitumor effect with the loaded anticancer agent. RHT-AgNPs demonstrated high drug loading efficiency (>86%) for anticancer drug epirubicin (EPI), and the resultant EPI-loaded RHT-AgNPs (RHT-AgNPs/EPI) nanoformulation exhibited unique pH- and glutathione (GSH)-responsive EPI release as well as pH-responsive Ag release behavior. The in vitro cytotoxicity assay indicated that RHT-AgNPs/EPI could significantly improve the effect of bacteria on the cytotoxicity of EPI against breast cancer cells (with an equivalent EPI concentration of 20 μg/mL). Moreover, in an S. aureus infection-associated 4T1 breast tumor-bearing Balb/c mouse model, intravenous administration of RHT-AgNPs/EPI (with an equivalent EPI amount of 5 mg/kg) effectively suppressed infectious inflammation and showed superior tumor suppression compared to the single EPI administration without inducing notable toxic effects on healthy tissues.