Ghosh Sujit Kumar, Khatua Pijus Kanti, Bhattacharya Subhash Chandra
Department of Chemistry, Jadavpur University, Calcutta 700032, India.
J Colloid Interface Sci. 2004 Nov 15;279(2):523-32. doi: 10.1016/j.jcis.2004.06.089.
The association of polyoxyethylene nonyl phenol (Igepal) in four different organic solvents such as chloroform, carbon tetrachloride, cyclohexane, and heptane has been studied. The critical micellar concentration of the reverse micelle (RM) formed in different nonaqueous media has been determined using four different techniques: UV-visible spectroscopy, fluorescence spectroscopy, Stokes shift, and NMR spectroscopic studies. From the correlation of cmc with hydrophile-lipophile balance (HLB), we have found that cmc decreases with decrease in HLB. The obtained cmc values using different methods have been found to be consistent and facilitate the determination of DeltaG values associated with the micellization. The association constant of the dye molecule Safranine T (ST) with the reverse micelle, aggregation number of the surfactant monomer, and location of fluorophore in the RM have been determined. The vertical ionization potential of Igepal, electron affinity of the dye, and the degree of charge transfer have been estimated by the theoretical AM1 calculations. A linear relationship has been obtained between cmc(s) and the ionization potential of the solvents. The polarity of the micelle solubilization sites has been determined from the solvatochromic shift, Kosower Z value, and ET(30) value.
研究了聚氧乙烯壬基酚（Igepal）在氯仿、四氯化碳、环己烷和庚烷这四种不同有机溶剂中的缔合情况。使用紫外可见光谱、荧光光谱、斯托克斯位移和核磁共振光谱研究这四种不同技术，测定了在不同非水介质中形成的反胶束（RM）的临界胶束浓度。通过临界胶束浓度与亲水亲油平衡（HLB）的相关性，我们发现临界胶束浓度随亲水亲油平衡的降低而降低。已发现使用不同方法获得的临界胶束浓度值是一致的，并且有助于确定与胶束化相关的ΔG值。测定了染料分子藏红T（ST）与反胶束的缔合常数、表面活性剂单体的聚集数以及荧光团在反胶束中的位置。通过理论AM1计算估计了Igepal的垂直电离势、染料的电子亲和势以及电荷转移程度。已获得临界胶束浓度与溶剂电离势之间的线性关系。根据溶剂化显色位移、Kosower Z值和ET(30)值确定了胶束增溶位点的极性。
