To elucidate the effect of aromatic side chains on dilational rheological properties of N-acyltaurate amphiphiles at the decane–water interface, the interfacial rheological properties of sodium N-2-(2-naphthoxy)-tetradecanoyltaurinate (12+N-T) and sodium N-2-(p-butylphenoxy)-tetradecanoyltaurinate (12+4B-T) were investigated utilizing the drop shape analysis method. The effects of adsorption time, interfacial pressure, oscillating frequency, and bulk concentration on the interfacial dilational modulus and phase angle were explored. The results show that the 12+4B-T molecule with a longer hydrophobic chain shows a higher ability for reducing the interfacial tension (IFT). In addition, the interfacial films of both 12+N-T and 12+4B-T are dominated by diffusion exchange at high concentrations. The rigidity of molecules controls the diffusion exchange at low concentrations, while the molecular hydrodynamic radius determines the diffusion exchange at high concentrations. Thus, at low concentrations, the stronger intermolecular interaction between 12+4B-T molecules results in higher dilational modulus values than 12+N-T. When approaching the CMC (critical micelle concentration) value, the rapid diffusion exchange of 12+4B-T between the sublayer micelles and the interface causes a significant decrease in the dilational modulus, while the relatively rigid structure of 12+N-T enables a higher dilational modulus than 12+4B-T. What's more, the longer hydrophobic chain allows 12+4B-T molecules to escape from the interface more easily, resulting in a higher phase angle at low concentrations. However, the diffusion exchange of 12+4B-T is slower than that of 12+N-T, which results in lower phase angles for 12+4B-T than 12+N-T at high concentrations. In general, the introduction of a rigid naphthalene ring in the molecular structure gives the interfacial film greater strength at high concentration. The research results in this paper provide a new technique for the strength regulation of interfacial surfactant adsorption films.

中文翻译：

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芳香族侧链对N-酰基牛磺酸盐两亲物在水-癸烷界面膨胀流变性质的影响

为了阐明芳香族侧链对N -酰基牛磺酸盐两亲物在癸烷-水界面的膨胀流变性质的影响，研究了N -2-(2-萘氧基)-十四烷酰基牛磺酸钠 (12+NT) 和N -钠的界面流变性质。利用液滴形状分析方法研究了2-(对丁基苯氧基)-十四烷酰基牛磺酸盐(12+4B-T)。探讨了吸附时间、界面压力、振荡频率和体积浓度对界面膨胀模量和相角的影响。结果表明，具有较长疏水链的12+4B-T分子表现出较高的降低界面张力（IFT）的能力。此外，12+NT和12+4B-T的界面膜在高浓度下均以扩散交换为主。分子的刚性控制低浓度下的扩散交换，而分子流体动力学半径决定高浓度下的扩散交换。因此，在低浓度下，12+4B-T分子之间更强的分子间相互作用导致比12+NT更高的扩张模量值。当接近CMC（临界胶束浓度）值时，12+4B-T在亚层胶束与界面之间的快速扩散交换导致膨胀模量显着下降，而12+NT相对刚性的结构使其具有更高的膨胀模量。模量高于12+4B-T。更重要的是，更长的疏水链使得12+4B-T分子更容易从界面逃逸，从而在低浓度下产生更高的相角。然而，12+4B-T 的扩散交换比 12+NT 慢，这导致在高浓度下 12+4B-T 的相角低于 12+NT。一般来说，在分子结构中引入刚性萘环使得界面膜在高浓度下具有更大的强度。本文的研究成果为界面表面活性剂吸附膜的强度调控提供了一种新的技术。