Abstract

The applications of surfactants in various fields are gaining more attention, which makes full characterization of surfactants of growing interest. It is fundamental to measure the critical micelle concentration (CMC) as a parameter for characterizing surfactants. Spectroscopic methods for determination of CMC are more common, easier to perform, and in certain applications more accurate. In this review, different spectroscopic techniques and methods used for determination of CMC are discussed. These methods include direct UV/VIS Spectroscopy, which studies liquid surface curvature in thin wells using vertical detecting light beam with the wavelength set at 900 nm. The indirect UV/VIS Spectroscopic methods include using surface plasmon resonance or surface-enhanced Raman scattering of metal nanoparticles. Direct spectrofluorometric methods measure CMC based on the intrinsic fluorescence of the tested surfactants, and it was reserved for surfactants with intrinsic fluorescence such as Triton-X100. Indirect spectrofluorometric methods include measuring the change in fluorescence intensity, spectral shape, lifetime, polarization, or the solvatochromic shift of surfactant-dye solution. Other spectroscopic methods have been reported such as X-ray diffraction, nuclear magnetic resonance spectroscopy and small-angle neutron scattering. This review article discusses the spectroscopic methods developed for CMC determination with emphasis on the principle, applications, advantages, and limitations of each method.

摘要

表面活性剂在各个领域的应用越来越受到关注，这使得对表面活性剂的全面表征越来越感兴趣。测量临界胶束浓度 (CMC) 作为表征表面活性剂的参数至关重要。用于测定 CMC 的光谱方法更常见、更容易执行，并且在某些应用中更准确。在这篇综述中，讨论了用于测定 CMC 的不同光谱技术和方法。这些方法包括直接紫外/可见光谱法，它使用波长设置为 900 nm 的垂直检测光束研究薄孔中的液体表面曲率。间接 UV/VIS 光谱方法包括使用金属纳米粒子的表面等离子体共振或表面增强拉曼散射。直接荧光分光光度法是根据被测表面活性剂的固有荧光测量CMC，专用于Triton-X100等具有固有荧光的表面活性剂。间接荧光光谱法包括测量荧光强度、光谱形状、寿命、偏振或表面活性剂-染料溶液的溶剂化变色位移的变化。已经报道了其他光谱方法，例如 X 射线衍射、核磁共振光谱和小角中子散射。这篇评论文章讨论了为 CMC 测定开发的光谱方法，重点介绍了每种方法的原理、应用、优点和局限性。保留给具有本征荧光的表面活性剂，如 Triton-X100。间接荧光光谱法包括测量荧光强度、光谱形状、寿命、偏振或表面活性剂-染料溶液的溶剂化变色位移的变化。已经报道了其他光谱方法，例如 X 射线衍射、核磁共振光谱和小角中子散射。这篇评论文章讨论了为 CMC 测定开发的光谱方法，重点介绍了每种方法的原理、应用、优点和局限性。保留给具有本征荧光的表面活性剂，如 Triton-X100。间接荧光光谱法包括测量荧光强度、光谱形状、寿命、偏振或表面活性剂-染料溶液的溶剂化变色位移的变化。已经报道了其他光谱方法，例如 X 射线衍射、核磁共振光谱和小角中子散射。这篇评论文章讨论了为 CMC 测定开发的光谱方法，重点介绍了每种方法的原理、应用、优点和局限性。已经报道了其他光谱方法，例如 X 射线衍射、核磁共振光谱和小角中子散射。这篇评论文章讨论了为 CMC 测定开发的光谱方法，重点介绍了每种方法的原理、应用、优点和局限性。已经报道了其他光谱方法，例如 X 射线衍射、核磁共振光谱和小角中子散射。这篇评论文章讨论了为 CMC 测定开发的光谱方法，重点介绍了每种方法的原理、应用、优点和局限性。