The influence of cohumulone on thermodynamics of micellization of alkyl trimethyl ammonium bromide surfactants

In the present study, micellization of three cationic surfactants, dodecytrimethylammonium bromide (DTAB), tetradecytrimethylammonium bromide (TTAB), and hexadecyltrimethylammonium bromide (HTAB), in the presence and absence of cohumulone (CH), was carefully examined with a wide variety of methods. Critical Micelle Concentration (CMC) was determined using fluorescence (DTAB: 12.2 mM, CH added: 14.50 mM; TTAB: 2.38 mM, CH added: 4.80 mM; HTAB: 0.66 mM, CH added: 2.29 mM) and conductivity measurements. The thermodynamics of micellization was thoroughly examined using Isothermal Titration Calorimetry (Δ H ° mic (kJ/mol) at 25 °C: DTAB: -1.48; added CH: -1.57; TTAB: -3.88; added CH: -4.16; HTAB: -7.98; added CH: -7.19). The effect of cohumulone on micelle dimensions was observed with Dynamic Light Scattering (DLS; DTAB: 4.2 nm, CH added: 8.1 nm; TTAB: 3.6 nm, CH added: 5.9 nm; HTAB: 3.9 nm, CH added: 5.4 nm). Based on these results, a description of the micellization of alkyltrimethylammonium bromide surfactants in the presence of CH was developed. While CMC and micellization thermodynamics remain virtually unaltered in the presence of CH, micelle size and its polydispersity get significantly increased, and the micelle formation process is notably changed. • Cohumulone slightly affects the CMC of alkyl trimethyl ammonium bromide surfactants. • The presence of cohumulone increases the micelle size of chosen surfactants. • Addition of cohumulone does not significantly change the thermodynamics of micellization. • The micelle formation process is significantly altered in the presence of cohumulone.