芘稳态荧光法研究疏水碳原子数对两性型表面活性剂聚集行为的影响

The Effect of the Number of Hydrophobic Carbon Atoms on the Aggregation Behavior of Amphoteric Surfactant was Studied by Pyrene Steady-state Fluorescence Method

为研究疏水碳原子数对两性型表面活性剂聚集行为的影响,笔者以疏水性芘为荧光探针,测定了疏水链碳原子数(m)分别为12、14、16、18的磺酸钠两性型表面活性剂(记作S_(m))的临界胶束浓度(CMC),并确定了合成样品的微极性。以373 nm与384 nm的荧光强度之比I1/I3与样品浓度的关系可知,样品S12~S18的CMC分别为7.90×10^(-4)mol/L、5.39×10^(-4)mol/L、4.72×10^(-4)mol/L、4.14×10^(-4)mol/L,平衡I1/I3分别为1.667、1.211、1.272、1.294。表明随着疏水链碳原子数的增加,合成样品形成有序聚集体的能力增强,所具有的表面活性随之增加,其中疏水碳原子数为14的样品S14形成聚集体的结构最为紧密。

In order to study the effect of hydrophobic carbon atomic number on the aggregation behavior of amphoteric surfactants,the critical micellar concentration(CMC)of sodium sulfonate amphoteric surfactants(S_(m))with hydrophobic carbon atomic number(m)of 12,14,16 and 18 was determined by using hydrophobic pyrene as a fluorescent probe,and the micropolarity of the synthesized samples was determined.Based on the relationship between fluorescence intensity ratio I1/I3 at 373 nm and 384 nm and sample concentration,CMC of S12~S18 is 7.90×10^(-4)mol/L,5.39×10^(-4)mol/L,4.72×10^(-4)mol/L,4.14×10^(-4)mol/L,respectively.The equilibrium I1/I3 were 1.667,1.211,1.272 and 1.294,respectively.The results showed that with the increase of the number of hydrophobic carbon atoms,the ability of the synthesized sample to form ordered aggregates was enhanced,and the surface activity of the synthesized sample was increased,among which the sample S14 with the number of hydrophobic carbon atoms was 14 formed the tightest aggregate structure.