“…The efforts of scientists resulted in obtaining gemini surfactants with different head groups that can be anionic (e.g., alkylbenzene sulfonate, phosphate, dicarboxylate) [ 16 , 17 , 18 ], cationic (e.g., quaternary ammonium, arginine, lysine, serine, imidazolium, morpholinium, pyridinium, piperidinium, pyrrolidinium) [ 19 , 20 , 21 , 22 , 23 , 24 , 25 ], zwitterionic (e.g., betaine, heterogemini surfactants) [ 26 , 27 ], and non-ionic (e.g., 3-deoxy-D-glucitol, lactobionic acid residues) [ 28 , 29 ]. Moreover, plenty of different spacers were used such as hydrocarbons (saturated and unsaturated), stilbene units, p-xylenes, cyclohexane derivatives, disulfides, lysine esters, triazines, or even borates [ 30 , 31 , 32 , 33 , 34 , 35 ]. Formally, geminis that are asymmetric (e.g., those with a lysine spacer) are classified as geminoid or gemini-like surfactans [ 36 , 37 ].…”