Spontaneous Crystallization at the Air−Water Interface:  An Unusual Feature of Gemini Surfactant with a Rigid Spacer

Abstract

An unusual feature which involves spontaneous crystallization at the air-water interface from aqueous solution was reported for a water-soluble gemini surfactant with xylyl spacer, (p-phenylenedimethylene) bis(dodecyldimethylammonium) dibromide. Polarizing microscope, in situ confocal microscopic Raman spectroscopy, and powder XRD were used to characterize the structure of the crystal and investigate the driving force for nucleation. It was inferred that, besides the surface enrichment of amphiphiles and the intra- and intermolecular interaction of alkyl chains, the pi-pi stacking interaction of benzene rings plays an extraordinary role in promoting nucleation and stabilizing crystal structure. A mechanism for constructing supramolecular architectures in situ at the air-water interface directly from aqueous solution via water-soluble amphiphiles with groups favorable for pi-pi stacking interaction was proposed.

Monolayer effect of a gemini surfactant with a rigid biphenyl spacer on its self-crystallization at the air/liquid interface

“…Recently, there have been a few reports concerning the crystallization of a single compound at the air/solution interface (Kadam et al, 2011;Zhou et al, 2006). Kadam et al (2011) found that paracetamol might form single crystals at the air/ liquid interface.…”

“…Kadam et al (2011) found that paracetamol might form single crystals at the air/ liquid interface. In our previous work, we discovered that p-xylylenebis(dodecyldimethylammonium bromide) (12-Ar) ISSN 1600-5767 # 2015 International Union of Crystallography with a rigid (xylylene) spacer could be used to fabricate an interfacial crystal with a small size (Zhou et al, 2006). Since a soluble surfactant can spontaneously form a Gibbs monolayer at the air/liquid interface, we were led to hypothesize that the Gibbs monolayer of soluble amphiphiles has an important effect on the interfacial crystallization as the Langmuir monolayer.…”

Self‐Assembly of Anionic Gemini‐Surfactant‐Assisted Fabrication of Copper Oxide Nanostructures

“…In this study, it suggests the importance of hydrogen bonds for the stability of the aggregations as well as their influence on the aggregation morphology. The existence of rigid segments refers to mesogenic groups endowed with sufficient anisotropy in both attractive and repulsive forces to contribute strongly to the liquid‐crystal phase formation ,. Upon the introduction of biphenyl groups, the Van Der Waals Interactions between the surfactant moleciles can be enhanced, subsequently resulting in stable self‐assembled aggregations.…”

Hexagonal Nanoarchitecture of Composite Monolayer of Magnetite Nanoparticles and Geminus Surfactant 1,3‐Propylenebis(dodecyldimethylammonium) Dibromide

“…1,7,[22][23][24][25][26][27][28] For instance, Zhang et al 29 once found self-organized domains in a ring pattern of a samarium complex bound by a β-diketone ligand TTA-Sm(TTA) 3 Phen (TTA denotes thenoyltrifluoroacetone; Phen denotes 1,10-phenanthroline). Stearic acid was mixed with the samarium complex, which formed highly ordered round domains.…”