Surfactants are chemically amphiphi

Surfactants are chemically amphiphilic molecules composed of a hydrophilic head group (polar) and a hydrophobic tail group (nonpolar). According to the different charges the polar head bears, surfactants can be divided into anionic, cationic, zwitterionic and non-ionic types [1]. The unique bipolar structure endows surfactant molecules a variety of properties like self-assembling, reducing surface tension, etc., which makes them widely used in household cleaning detergents, as well as industrial and agricultural products [2]. The increasing use of surfactants and irregular treatments have caused serious environmental problems in soil and water, which makes them well-known environmental pollutants [3]. Particularly, anionic surfactants have been produced and used as the largest group of surfactants and deserve special attention as they cause more environmental problems. Fluorescent sensors have drawn increasing attention for detection of anionic surfactants due to its simple operation, high sensitivity, and easy combination with other optical signals. So far, a variety of fluorescent sensors have been reported for detecting anionic surfactants. For example, Zhang and co-workers developed cationic polythiophenebased probes as colorimetric and fluorescent sensors for selectively recognizing anionic surfactants like SDS, SDBS, SLS, and SDC over other types of surfactants [4,5]. Li et al. reported a conjugated polyelectrolyte/dye complex-based colorimetric and fluorescent sensor that can selectively detect anionic surfactants like SDS, SDBS, SLS, SDC [2]. Moreover, Li and co-workers synthesized a series of cationic amphiphilic probes as colorimetric and fluorescent sensors for selective detection of anionic surfactants like SDS, SDBS, SDSO, and SD [6]. Tang’s group and Zeng’s group developed aggregation-induced emission (AIE) active probes for selective recognizing anionic surfactants like SDBS and SDS over other type of surfactant