Physicochemical Properties of Acylglutamic Acid-Alkylamine Complexes in Aqueous Media

Abstract

IntroductionGemini surfactant is a dimer of monomeric surfactants linked by a space unit, being composed of two hydrophilic headgroups and two hydrophobic chains in a molecule 1, 2 . Gemini surfactants have been attracted as a new type of surfactants because of their excellent micellization efficiency at low concentrations and good solubility in water 1, 2 . Thus, gemini surfactants are generally categorized into an eco-friendly surfactant. However, their synthesis and purification processes are usually complicated, and this leads to their high selling price in the market.Based on these backgrounds, functionally-equivalent materials with gemini surfactants have been investigated, including dicarboxylic acid-alkylamine or diamine-alkyl carboxylic acid complexes, as shown in the following references. The stoichiometric complex formation is simply based on the proton transfer from the acid to the amine. This does not lead to an increase in the ionic strength in solution, which is significantly different from systems of catanionic cationic and anionic surfactant mixtures. They are sometimes called gemini-like amphiphile 3 , pseudogemini surfactant 4 6 , or counterion-coupled gemini surfactant cocogem 7,8 . Such noncovalent-type amphiphiles have been investigated in the aspect of surface tension in water 7 and rheology based on the formation of wormlike

Rheology of α-Gel Formed by Amino Acid-Based Surfactant with Long-Chain Alcohol: Effects of Inorganic Salt Concentration

“…N -Dodecanoylglutamic acid (C12Glu) was synthesized according to the procedure described in our previous papers. , C12Glu was neutralized using NaOH at a fixed mole ratio, C12Glu:NaOH = 1:2, to yield C12Glu-2Na. C16OH and NaCl were purchased from FUJIFILM Wako Pure Chemical Corporation and used without further purification.…”

Aqueous solution thickening of amino acid‐based surfactant by alkylpyrrolidone

“…For amino acid-based surfactant aqueous solutions, as literatures reported (Faustino et al, 2011;Ghosh & Ray, 2014;Lu et al, 2015;Sakai et al, 2012Sakai et al, , 2016Vu et al, 2020;Yoshikawa et al, 2020), another approach to building viscosity without polymer additives is by formulating them under appropriate pH conditions, in which the low pH is favorable for the formation of longer-range structures including wormlike micelles. Therefore, the effect of pH on steady-shear viscosity at varying shear rate was investigated in 10 wt% SLSar/ water/5 wt% C12P and 15 wt% SLSar/water systems.…”

“…triethyleneglycol alkyl ether (Shrestha et al, 2008;Shrestha et al, 2009aShrestha et al, , 2009b, alkanolamide, and monoglycerides. More recently, Sakai et al reported a novel way to acquire highly viscoelastic micellar solutions by a series of pseudogemini amino acid-based surfactants, which fabricated from nonsurface-active compounds, such as alkylamine, dodecyldimethylamine, and dodecylmethylamine, upon acidÀalkali reaction with acylglutamic acid (Sakai et al, 2012(Sakai et al, , 2016Yoshikawa et al, 2020).…”