Iron Binding in an Ethylenediaminetetracetic Acid‐Based Gemini Surfactant Monolayer Film

Physicochemical Properties of Monolayers of a Gemini Surfactant with a Minimal-Length Spacer

Fundamental physical chemical properties of monolayers formed from a new anionic gemini surfactant with a minimal-length (single-bond) spacer unit have been investigated at the air-water interface and compared with those of monolayers formed from affiliated comparator surfactants. The minimal spacer surfactant, dubbed C₁₈-0-C₁₈, exhibited strikingly different packing characteristics from an anionic gemini surfactant with a comparatively bulkier headgroup, including the formation of close-packed, crystalline films, and shared similar characteristics to simple fatty acid-based monolayers. Monolayers of C₁₈-0-C₁₈ also exhibited good stability at the air-water interface and transferred with reasonable efficiency to solid substrates, although the film integrity was compromised during the transfer. Results from this work suggest that the single-bond spacer approach might be more broadly useful for designing gemini surfactants that pack efficiently into ordered monolayers.

Pattern Formation in Phase-Separated Langmuir and Langmuir Monolayer Films

Mixed monolayer films comprising hydrogenated and fluorinated surfactants can undergo phase separation to produce interfaces with diverse structures at the micrometer and nanometer scales. This review discusses our progress over the past decade to probe the relationship that exists between the molecular structure of the surfactants that comprise the films and the overall patterns formed in the monolayers. We review two main classes of mixed perfluorocarbon-hydrocarbon surfactant systems, including fatty acids and a recently developed family of EDTA-based gemini surfactants. In addition to summarizing the state-of-the-art of this field, the key scientific questions and relationships that require further elucidation are discussed, along with directions for continuing research into this fascinating area of research.