Synthesis and Solution Properties of a Double‐Tailed Quaternary Ammonium Surfactant with a Protrudent Head Group

Abstract

Modification of the molecular structure of surfactants is an effective method for exploring their selfassembly. A double-tailed quaternary ammonium surfactant with a protrudent head group, namely 2-octyldecyltrimethylammonium bromide (2-ODTAB) was synthesized, and the solution properties were investigated by surface tension, dynamic light scattering, and cryogenic TEM. A comparative study was also performed on the traditional double-tailed homologue surfactants dioctyldimethylammonium bromide (8-8), didecyldimethylammonium bromide (10-10), and didodecyldimethylammonium bromide (12-12). The results showed that 2-ODTAB was more effective at lowering surface tension and in forming stable vesicles than traditional double-tailed surfactants with similar alkyl chain length. The reason is attributed to the improved structure of 2-ODTAB, in which the two alkyl tails are connected to the ionic head group by one carbon atom. This structure imparts more freedom to the head group and thus favors formation of more stable aggregates at low concentration. In addition, the lower limit of the alkyl chain length of the double-tailed surfactants for forming stable vesicles was illustrated.

Regulating Droplet Impact and Wetting Behaviors on Hydrophobic Weed Leaves by a Double-Chain Cationic Surfactant

“…Didecyldimethylammonium bromide (DDAB), a double-chain cationic surfactant, contains a hydrophilic quaternary ammonium head group and two hydrophobic alkyl tails (Scheme ). Once dispersed in water, two hydrophobic chains of DDAB tend to stack with each other to reduce the energy of the system, thus making DDAB adsorb at the liquid–air interface or form aggregates with a low critical micelle concentration and outstanding surface activity. , In addition, DDAB has not been used as an adjuvant in agriculture to date. In this paper, we systematically investigated the physicochemical properties of DDAB and its role in regulating droplet impact and wetting on hydrophobic paraffin and Chenopodium album L. leaf surfaces.…”

Toroidal micelles formed in viscoelastic aqueous solutions of a double-tailed surfactant with two quaternary ammonium head groups

“…According to the packing parameter theory, such surfactants tend to form vesicles or lamellar phases. 18,19 The typical double-tailed surfactants, including didodecyldimethylammonium bromide (DDAB), dimethyldimyristylammonium bromide (DTDAB), and dihexadecyldimethylammonium bromide (DHDAB), usually form vesicular aggregates above critical concentrations. [20][21][22] Certain double-tailed surfactants containing functional groups can also form vesicular aggregates with a stimuli-responsive behavior.…”