Departamento de Química e INQUISUR, Universidad Nacional del Sur, CONICET, Bahía Blanca, Argentina.
Colloids Surf B Biointerfaces. 2012 Jan 1;89:265-70. doi: 10.1016/j.colsurfb.2011.09.030. Epub 2011 Sep 22.
Ascorbyl palmitate (Asc16) in polyethyleneglycol 400 (PEG 400)-water mixtures at weight fractions (w/w) between 0.05 and 1.0 were studied by differential scanning calorimetry (DSC) and polarizing microscopy (PM) at different temperatures. The employed PEG 400-water proportions were: 0-25-50% and 75% of polymer. A complete phase diagram was determined for each PEG 400-water mixture. A cubic mesophase and two (probably three) lamellar mesophases were detected in different regions of the phase diagrams. The addition of PEG 400 to the Asc16-water system shifts the limits of the liquid crystalline domains to lower temperature and surfactant concentration. At weight fraction of PEG 400≥50%, the limits of the domain of existence of cubic mesophase shift to low surfactant concentration compared with water-rich systems. The hydrated crystals are Asc16.2·6H(2)O. If the proportion of water is lower than that value, a mixture of hydrated and anhydrous crystals appears. Heating these crystals produce waxy crystals having melted hydrocarbon bilayers retaining their crystalline structure because the polar bilayers are still rigid.
在重量分数（w/w）为 0.05 至 1.0 之间的聚乙二醇 400（PEG 400）-水混合物中的抗坏血酸棕榈酸酯（Asc16），通过差示扫描量热法（DSC）和偏光显微镜（PM）在不同温度下进行了研究。所采用的 PEG 400-水的比例为：0-25-50%和 75%的聚合物。为每种 PEG 400-水混合物确定了完整的相图。在相图的不同区域检测到立方中间相和两个（可能三个）层状中间相。PEG 400 的添加将液晶区域的界限移至较低的温度和表面活性剂浓度。在 PEG 400 的重量分数≥50%时，与富含水的系统相比，立方中间相的存在区域的界限向低表面活性剂浓度转移。水合晶体是 Asc16.2·6H(2)O。如果水的比例低于该值，则会出现水合和无水晶体的混合物。加热这些晶体产生蜡状晶体，其中融化的烃双层保留其晶体结构，因为极性双层仍然是刚性的。
