The surface adsorption, aggregate structure and antibacterial activity of Gemini quaternary ammonium surfactants with carboxylic counterions

Abstract

A group of Gemini quaternary ammonium surfactants with the formula C n H 2 n +1 CONH(CH 2 ) 2 N + (CH 3 ) 2 (CH 2 ) 2 N + (CH 3 ) 2 (CH 2 ) 2 NHCOC n H 2 n +1 · 2Y ( n = 11, 13 and 15, Y = HCOO − , CH 3 COO − and CH 3 CHOHCOO − ) have been synthesized by a counterion conversion process and characterized by Fourier transform infrared spectroscopy and mass spectroscopy. Their adsorption and self-aggregation properties are investigated by surface tension, conductivity, dynamic light scattering and transmission electron microscopy (TEM) measurements. The results show that these surfactants reduce the surface tension of water to a minimum value of 26.51 mN m −1 at a concentration of 5.72 × 10 −2 mmol l −1 . Furthermore, the increased alkyl chain length of the carboxylic counterions leads to the increased critical micelle concentration, the decreased degree of counterion binding ( β ) and the decreased self-assembly tendency, but the minimum area per surfactant molecule ( A min ) adsorbed at the air–aqueous solution are similar. TEM images reveal that these surfactants self-assemble spontaneously into aggregates with vesicle or bilayer structures. It is also found that they have superior antibacterial activity at a concentration of 0.1 g l −1 . The high surface activity and high antibacterial activity of the Gemini quaternary ammonium salt surfactants containing different carboxylic counterions bring more possibilities for the application in the field of biomedicine.

Surface Activities, Antibacterial Activity and Corrosion Inhibition Properties of Gemini Quaternary Ammonium Surfactants with Amido Group and Carboxylic Counterions

“…The 17-2-17-2Y gemini surfactants were synthesized according to the method reported in our previous paper 13,18 . The general formula and synthesis procedure for the 17-2-17-2Y surfactants were shown in Scheme 1.…”

“…Table 1 shows that these three species of carboxylic counterions have little effect on the values of Γ max and A min . The reason may be that, these short alkyl chain counterions such as formic acid and acetate have strong hydrophilicity and weak hydrophobicity, will not or seldom insert into the surface adsorption layer, thus the surface adsorption parameters of these gemini quaternary ammonium surfactants have little change 13 .…”

“…The bacteriostatic efficiency is calculated according to the following formula: where OD 0 and OD 1 refer to the OD values of the bacillus without surfactants and with surfactants at the same time, respectively. According to our previous work 13 , the values at 15 h are used to evaluate the surfactant inhibition for Pseudomonas aeruginosa and Staphylococcus aureus, while the values at 10 h and 12 h are used to evaluate for Escherichia coli and Bacillus subtilis, respectively. The bacteriostatic efficiency of these gemini surfactants solution and 0.1 g L 1 benzalkonium chloride solution are listed in Table 2.…”

Effects of various media on micellization, adsorption and thermodynamic behaviour of imipramine hydrochloride and antimicrobial surfactant mixtures

“…Most surface-active agents are amphiphilic organic molecules, consisting of hydrophobic groups in a hydrocarbon tail and hydrophilic groups as the head of a single molecule [1][2][3][4][5][6]. The association within amphiphilic molecules (such as surfactants) called micelles that happens due to the balance between hydrophilic and hydrophobic interactions is the critical micelle concentration (cmc) [7][8][9][10][11][12][13]. Because of their exceptional structural characteristics and good solubilization properties [6], micelles have been extensively used in industries such as pharmaceuticals, dyes, make-up and environmental management [4,6].…”

Catalytic influence of 16- s -16 gemini surfactants on the rate constant of histidine and ninhydrin

“…Gemini surfactant comprises two traditional monomeric surfactants connected by a spacer [10][11][12][13][14][15]. Compared with conventional surfactants (single head and single chain), gemini surfactants show unique physico-chemical behaviour that depends upon the nature of hydrophilic head, hydrophobic tail and spacer chain length.…”