Akram Mohd, Bhat Imtiyaz Ahmad
Department of Chemistry, Aligarh Muslim University , Aligarh-202002, India.
J Phys Chem B. 2015 Feb 26;119(8):3499-509. doi: 10.1021/jp5097822. Epub 2015 Jan 23.
We have investigated the effect of salt additives (NaCl, Na₂SO₄, Na₃PO₄, NaTos, and NaAn) on the aggregation behavior of a cleavable biodegradable ester-bonded dicationic gemini surfactant, ethane-1,2-diyl bis(N,N-dimethyl-N-hexadecylammoniumacetoxy) dichloride (16-E2-16). A multitechnique approach employing tensiometry, fluorescence, proton magnetic resonance (¹H NMR), transmission electron microscopy (TEM), absorption spectrophotometry (UV), and Fourier transform infrared spectroscopy (FTIR) was utilized to probe physicochemical fluctuations. Appreciable changes were observed in various physicochemical parameters, viz., critical micelle concentration (CMC), surface excess concentration (Γ(max)), minimum area per headgroup (A(min)), free energy of micellization (ΔG(mic)°), free energy of adsorption (ΔG(ads)°), and aggregation number (N(agg)). Counter ions were found to affect through electrostatic and hydrophobic influence obeying the overall trend as NaAn > NaTos > Na₃PO₄ > Na₂SO₄ > NaCl. ¹H NMR, TEM, UV, and FTIR results reveal microstructure evolution and phase transitions. These results thus provide deeper insights in understanding of self-aggregation and microstructure evolution of biocompatible (green) aqueous systems of the gemini surfactant and their implications in the biomedical and pharmaceutical world, which could be helpful to improve their bioavailability and other biochemical aspects like drug delivery and gene transfection.
我们研究了盐添加剂（氯化钠、硫酸钠、磷酸钠、对甲苯磺酸钠和对氨基苯磺酸钠）对一种可裂解的可生物降解酯键型双阳离子 Gemini 表面活性剂——乙烷-1,2-二基双（N,N-二甲基-N-十六烷基铵乙酰氧基）二氯化物（16-E2-16）聚集行为的影响。采用了一种多技术方法，包括张力测定法、荧光法、质子磁共振（¹H NMR）、透射电子显微镜（TEM）、吸收分光光度法（UV）和傅里叶变换红外光谱法（FTIR）来探测物理化学波动。在各种物理化学参数中观察到了明显变化，即临界胶束浓度（CMC）、表面过剩浓度（Γ(max)）、每个头基的最小面积（A(min)）、胶束化自由能（ΔG(mic)°）、吸附自由能（ΔG(ads)°）和聚集数（N(agg)）。发现抗衡离子通过静电和疏水作用产生影响，遵循以下总体趋势：对氨基苯磺酸钠 > 对甲苯磺酸钠 > 磷酸钠 > 硫酸钠 > 氯化钠。¹H NMR、TEM、UV 和 FTIR 结果揭示了微观结构的演变和相变。因此，这些结果为理解 Gemini 表面活性剂的生物相容性（绿色）水性体系的自聚集和微观结构演变及其在生物医学和制药领域的意义提供了更深入的见解，这有助于提高它们的生物利用度以及其他生化方面，如药物递送和基因转染。
