Synthesis Of A Photosensitive Surfactantcontaining Fluorine And Its Interface Properties

The surfactants containing fluorine have the characteristics of"three highs"and"two phobias",and play a significant role in the fields of fire protection,industry,medicine,etc.The photosensitive properties of the azobenzene molecureshave been used in biomedicine,environmental remediation,and nanotechnology.We studied the interfacial properties of the photosensitive surfactantcontaining fluorine（FAS）.Moreover,we investigated the effects of light irradiation on the interfacial properties of the surfactant.Two photosensitive surfactants（FAS and CAS）were synthesized,and their structures were characterized by ¹H NMR and IR.The surfactant,CAS,has no fluorine in its molecure structure.The values ofГ_maxand p C₂₀ of FAS were greater than those of CAS.The cmc,γ_cmc,and A _min of FAS were less than those of CAS.The wettability of quartz was measured.The contact angle of FAS on quartz surface is apparently larger than that of CAS.The surfactant containing fluorine improves the hydrophobicity of the quartz surface.The surface tension of the surfactants（FAS）and（CAS） in the aqueous solutions was measured under the different light irradiation.The effects of the light irradiation and the inorganic salt on the surface properties of the surfactants were studied.The results show that after UV irradiation,γ_cmc,and A_minare increased;Г_maxis decreased,and p C₂₀is decreased.We studied the effect of surfactants（FAS and CAS） on the wettability of the quartz surface.The results show that the contact angles are increased with an increase inthe concentration of FAS,andrechesa maximum.Then,the contact angle is decreased.After the UV light irradiation,the adhesion force is increased,and the adhesion work is decreased,indicating that the wettability of quartz is enhanced by the UV light irradiation.After adding the surfactant（FAS）into the water,the zeta potential of quartz is increased.Finally,QCM-D was used to study the real-time dynamic adsorption process of the surfactant（FAS）on the quartz surface.The adsorption mechanism was analyzed.Under the UV light irradiation,the quality and thickness of the adsorption film are decreased.The irradiation of UV light reduces the adsorption of the surfactant on the quartz.