梳状结构硅表面活性剂的溶液性质

Solution Properties of Comb Structure Silicone Surfactants

采用氢硅化法制备得到了一系列具有梳状结构的非离子有机硅表面活性剂(PESO)。利用红外光谱和核磁共振氢谱对产物的结构进行了表征,分析了疏水基团的含量对PESO表面活性剂表面张力和临界胶束浓度的影响,研究了PESO表面活性剂在水溶液表面的吸附现象及在水溶液中的聚集行为,探讨了其在水溶液中形成的胶束的尺寸和分布。研究表明,随着疏水组分含氢硅油(PHMS)含量的增加,PESO表面活性剂分子越易缔合形成胶束且胶束的平均粒径增大。当PHMS含量由25%增加至67%时,临界胶束浓度(CMC)由0.828 g/L降至0.613 g/L,γCMC可降至22.11 mN/m,表面吸附量(Γ)可达3.31μmol/m2,每个表面活性剂分子吸附在空气/水界面的平均面积(A)仅为0.502 nm2,PESO表现出较好的表面活性。此外,荧光光谱法研究PESO聚合物在水溶液中的聚集行为发现,随着表面活性剂浓度的增加,第一、第三发射峰的荧光强度比值(I1/I3)不断减小,达到PESO的临界缔合浓度后,芘分子增溶于PESO胶束中,I1/I3趋于恒定。

A series of non-ionic organosilicone surfactants with comb structure( PESO) were prepared through hydrosilylation method. The structure of PESO polymers was characterized via infrared spectroscopy and nuclear magnetic resonance hydrogen spectrum. Then,the effects of hydrophobic group content on surface property of PESO surfactant were studied. The adsorption behavior of PESO surfactant on the air /water interface and the aggregation behavior of PESO surfactant in aqueous solution were discussed. The size and distribution of PESO micelle were also investigated. The results show that it is easier for PESO molecules to associate with each other to form micelles with increasing the content of hydrophobic groups. And the average size of micelles increases as well. When the content of PHMS increases from25% to 67%,the value of CMC decreases from 0. 828 g /L to 0. 613 g /L. The surface tension is low to 22. 11 mN /m.Surface adsorption quantity of PESO is high to 3. 31 μmol /m2. The average size of each surfactant molecules adsorbed on the air /water boundary size is only 0. 502 nm2. So PESO surfactants have good surface activity. The aggregation behavior of PESO polymers in aqueous solution was studied by fluorescence spectrometry. The results show that I1/I3 value decreases continuously with increasing concentration of surfactant. I1/I3 tends to be a constant when the concentration of PESO reaches its critical association concentration due to pyrene molecules dissolved in PESO micelle.