Ghofrani Ali Akbar, Khadangi-Mahrood Mahmoodreza, Hejri Zahra, Khosroyar Susan
Department of Chemical Engineering, Quchan Branch, Islamic Azad University, Quchan, Iran.
Heliyon. 2024 Dec 24;11(1):e41468. doi: 10.1016/j.heliyon.2024.e41468. eCollection 2025 Jan 15.
An interface can be delicately designed using interactions between nanoparticles and surfactants by controlling surface properties such as activity and charge equilibrium. This study seeks to provide insights into how surfactant concentration impacts the stability and dynamics of nanoparticle-surfactant interfaces, with potential applications in material science and interface engineering. This study investigates the interactions between Graphene Function (Gr, Graphene function in this text refers to functionalizing the graphene sheets with -COOH groups via acidic reactions.), Polystyrene sulfonate (PSS), and the surfactant Cetyl trimethylammonium bromide (CTAB) at the air/water interface. We examined various ratios of CTAB to Gr-PSS to determine the effects of surfactant concentration, focusing on conditions up to the critical micelle concentration (CMC). Specifically, we utilized different concentrations of CTAB ranging from 0 to 1 CMC (0.82 mM), while the concentration of Gr-PSS varied between 0 and 1 wt% and 20-50 ppm. To analyze the dynamic interfacial properties, including dynamic surface tension and dilational viscoelasticity, we employed drop profile analysis tensiometry (PAT) to measure area perturbation frequency at the air/water interface. The study aimed to elucidate the behavior of the CTAB/Gr-PSS complex at this interface. We discussed the adsorption of the CTAB/Gr-PSS complex on the droplet surface and its varying roles by examining surface pressure across different area change domains and conducting elasticity measurements. The results indicate that the attachment of CTAB molecules to Gr particles and PSS leads to the formation of surface-active complexes. As the surfactant concentration increases, excess CTAB monomers compete with the CTAB/Gr-PSS complexes for access to the interfaces, causing the larger complexes to migrate into the liquid bulk, as confirmed by elasticity assessments.
通过控制诸如活性和电荷平衡等表面性质，利用纳米颗粒与表面活性剂之间的相互作用，可以精心设计界面。本研究旨在深入了解表面活性剂浓度如何影响纳米颗粒 - 表面活性剂界面的稳定性和动力学，在材料科学和界面工程领域具有潜在应用。本研究考察了石墨烯功能化材料（Gr，本文中的石墨烯功能化材料是指通过酸性反应使石墨烯片带有 -COOH 基团）、聚苯乙烯磺酸盐（PSS）与表面活性剂十六烷基三甲基溴化铵（CTAB）在气/水界面的相互作用。我们研究了 CTAB 与 Gr - PSS 的各种比例，以确定表面活性剂浓度的影响，重点关注直至临界胶束浓度（CMC）的条件。具体而言，我们使用了浓度范围从 0 到 1 CMC（0.82 mM）的不同 CTAB，而 Gr - PSS 的浓度在 0 到 1 wt%以及 20 - 50 ppm 之间变化。为了分析动态界面性质，包括动态表面张力和拉伸粘弹性，我们采用滴外形分析张力测量法（PAT）来测量气/水界面处的面积扰动频率。该研究旨在阐明 CTAB/Gr - PSS 复合物在此界面的行为。我们通过检查不同面积变化域的表面压力并进行弹性测量，讨论了 CTAB/Gr - PSS 复合物在液滴表面的吸附及其不同作用。结果表明，CTAB 分子与 Gr 颗粒和 PSS 的附着导致形成表面活性复合物。如弹性评估所证实，随着表面活性剂浓度增加，过量的 CTAB 单体与 CTAB/Gr - PSS 复合物竞争进入界面，导致较大的复合物迁移到液体主体中。
