The Determination of Critical Micelle Concentration in Surfactants.
Alicia Wood*, Stephanie Canning
Molecular aggregation leading to the formation of micelles is an important part of chemistry. This experiment studied the changes in critical micelle concentrations (CMC) of different surfactants in order to determine the most effective surfactant for a desired chemical task. Through graphical analysis, tests measuring fluorescence, absorbance and conductivity of sodium dodecylsulphate (SDS) surfactant were compared to a conductivity test of tetradecyl trimethyl ammonium bromide (TTaBr) surfactant in order to find and compare the CMC for each. The results proved that the calculation of the CMC of TTaBr (0.0050M) using conductivity was lower than that of SDS (0.0090M), meaning TTaBr has proven to be the most effective surfactant of the two when minimal chemical concentration is desired. The calculation of the CMC using absorbance technique provided the most accurate results (CMC at 0.0088M SDS at 250nm, 0.0069M SDS at 312nm) in accordance to the data trends from previous experimentation (CMC at 0.0078M). All CMC calculations were found to be mostly similar to that of the previous literature data provided.
Micelles are made up of tiny biological substances known as lipids. Fats, oils, certain vitamins and hormones, and most non-protein membrane components are made of lipids. Lipids are comprised of ionic, hydrophilic “heads” and long, hydrophobic, hydrocarbon chains known as the “tails”. In aqueous solutions, lipids aggregate into micellar conformation in order to reduce exposure of the hydrophobic tails to the surrounding aqueous solution. In other words, these small lipids pack together forming a spherical micelle, keeping the hydrocarbon tails out of contact with water. Lipids have the capability of performing such a phenomenon due to an interaction known as van der Waals envelope. Van der Waals envelope creates a conical encasing...