Perfluorooctane sulfonate (PFOS) has attracted more and more attention because of its persistence, bioaccumulation and potential ecotoxicity. Although the electrostatic interaction between surfactant and dye has been used for PFOS detection, there still exist a problem in selectivity and some phenomenon also should be explored. Herein, two types of multi-head cationic siloxanes (M1 and D1) based “turn on” fluorescent system were designed for PFOS detection and were further used for exploring interaction between surfactant and dye. Cationic group (quaternary ammonium salt) was introduced into siloxane via thiol-ene click reaction. Two types of multi-head siloxanes with different amounts of cationic group and steric structure were obtained and showed a high selective detection for PFOS. More important, we further explored the possible response mechanism by contracting fluorescence behavior of three types of cationic molecules (single-head, two-head, and four-head cationic group) and speculated the high selectivity was derived from the synergistic effect between electrostatic interaction and steric hindrance. Furthermore, the exploration about surfactant-dye interaction in this work provide a deeper understanding for electrostatic action and its application.

全氟辛烷磺酸（PFOS）因其持久性、生物累积性和潜在的生态毒性而受到越来越多的关注。虽然表面活性剂与染料之间的静电相互作用已被用于PFOS的检测，但仍存在选择性问题，一些现象也有待探索。在此，设计了两种基于多头阳离子硅氧烷（M1 和 D1）的“开启”荧光系统用于 PFOS 检测，并进一步用于探索表面活性剂和染料之间的相互作用。通过硫醇-烯点击反应将阳离子基团（季铵盐）引入硅氧烷。获得了两种具有不同数量的阳离子基团和空间结构的多头硅氧烷，对PFOS表现出高选择性检测。更重要，我们通过收缩三种阳离子分子（单头、双头和四头阳离子基团）的荧光行为进一步探索了可能的响应机制，并推测高选择性来自静电相互作用和空间位阻之间的协同效应. 此外，本工作对表面活性剂-染料相互作用的探索为静电作用及其应用提供了更深入的理解。