This study analyzes the equilibrium and dynamic surface tension curves of acidic and lactonic sophorolipids (SLs). It also investigates the dilational properties of the surface adsorptive film. Given their high hydrophobicity, lactonic SLs have lower surface tension and critical micelle concentration (CMC) than acidic SLs. As c_NaCl increases, the CMC values and the corresponding surface tension (γ_cmc) of acidic and lactonic SLs decrease gradually. For dynamic surface properties, lactonic SLs have a high diffusive rate from the bulk phase to the subsurface. At 0.05 CMC, the initial adsorption of acidic and lactonic SLs is diffusion-controlled. As c_surfactant increases, the values of diffusion coefficient (D) show a downward trend, and the mechanism is mixed kinetic diffusion. Adding NaCl increases the D values of acidic and lactonic SLs, and the influence degree for acidic SLs is more considerable than that for lactonic SLs.

As frequency (ω) increases (0.005∼0.5 Hz), the dilational elasticity increases, and the phase angle decrease. The dilational elasticity of acidic and lactonic SLs shows a low-frequency dependence. Compared with acidic SLs, lactonic SLs have better dynamic surface properties, which decrease the gradient of interfacial tension because of the interface deformation. Consequently, the lactonic SLs exhibit a relatively small dilational elasticity. At 0.1 Hz, the dilational elasticity of acidic and lactonic SLs reaches the maximum values at 0.05CMC and 0.075CMC, respectively. When c_surfactant rises near CMC, the phase angle increases obviously, and the dilational elasticity further decreases. This result is attributed to the fast exchange of surfactant molecules between the interface and the micelles.

本研究分析了酸性和内酯槐糖脂 (SL) 的平衡和动态表面张力曲线。它还研究了表面吸附膜的膨胀特性。鉴于其高疏水性，内酯 SL 比酸性 SL 具有更低的表面张力和临界胶束浓度 (CMC)。随着c _{NaCl 的}增加，酸性和内酯 SL的 CMC 值和相应的表面张力 ( γ _cmc ) 逐渐降低。对于动态表面特性，内酯 SL 具有从体相到次表面的高扩散率。在 0.05 CMC 时，酸性和内酯 SL 的初始吸附是扩散控制的。随着c_{表面活性剂的}增加，扩散系数（D)呈下降趋势，机制为混合动力扩散。添加 NaCl 增加了酸性和内酯 SLs的D值，并且对酸性 SLs 的影响程度比对内酯 SLs 的影响更大。

随着频率（ω）的增加（0.005∼0.5Hz），膨胀弹性增加，相角减小。酸性和内酯 SL 的扩张弹性显示出低频依赖性。与酸性 SLs 相比，内酯 SLs 具有更好的动态表面性质，由于界面变形而降低了界面张力梯度。因此，内酯 SL 表现出相对较小的扩张弹性。在 0.1 Hz 时，酸性和内酯 SL 的扩张弹性分别在 0.05CMC 和 0.075CMC 处达到最大值。当c_{表面活性剂}CMC 附近上升，相角明显增大，扩张弹性进一步减小。这一结果归因于界面和胶束之间表面活性剂分子的快速交换。