Emergence of a Lyotropic Lamellar Phase: Surfactant-Aqueous Phase Contact Experiments Examined with a Cryo-Transmission Electron Microscope

A phase penetration experiment has been conducted, employing a cryo-transmission electron microscope (cryo-TEM). With this technique, the phase transitions and the molecular rearrangement that result from the phase penetration can be studied on almost the molecular level. The technique has been applied to the emergence of a lyotropic lamellar liquid-crystalline phase, when dodecylbenzenesulfonic acid (HDoBS) is brought into contact with water or with an aqueous sodium hydroxide solution. Both phases are nebulized onto the grid. As a result, fingerprint patterns are observed by cryo-TEM, that emerge when the aqueous phase penetrates into a thin layer of surfactant. The pattern consists of a two-dimensional lamellar alignment of the surfactant molecules. In thicker parts of the surfactant layer, the penetration results in smaller units of molecular alignment.