The Association Structures and Sustainability of Methyl Red and Methylene Blue In Water Systems, A Nonionic Surfactants (Tween-40 And Tween-80) And Cyclohexane

Abstract

Surfactants mixed with water and oil will form associative structures such as microemulsions and liquid crystals. Microemulsion and liquid crystals can dissolve dyes. Dyestuff solubility is widely used in various industrial fields, for example in paints, textiles, cosmetics and inks. This study aimed to determine the association structure and the solubility of methyl red and methylene blue in the water system, the nonionic surfactant (Tween-40 and Tween-80) and cyclohexane. In this study, 2 association structures have been formed in the water system / Tween-40 / cyclohexane and 3 association structures in the water system / Tween-80 / cyclohexane. Determination of the association structure is done through visual observation and using parafilm at various points (± 200) in the phase diagram. Methyl red dyes are dissolved in microemulsions and liquid crystals in acidic pH while methylene blue is in alkaline pH so that a stable color is obtained. The average solubility of methyl red in microemulsion of 0.0032 g in 1 gram of the sample and the average solubility of methyl red in the liquid crystals is 0.0033 grams in 1 gram of sample. As for the average solubility of methylene blue in the microemulsion is 0.0013 grams in 1 gram of the sample and the average solubility of methylene blue in the liquid crystal by 0.0014 g in 1 gram of sample. The measurement of the refractive index in some samples showed methyl red and methylene blue dissolved homogeneously in the sample. The refractive index value of the sample after dissolving the dye is higher than the refractive index value before the dyestuff is dissolved, because the dye changes the composition of the sample. The viscosity of the microemulsion before the dyestuff is dissolved is lower than the viscosity that has been dissolved by the dyestuff.