Gemini　(or　dimeric)　surfactants　are　made　up　of　two　identical　amphiphilic　moieties　covalently　connected　at　the　level　of　the　headgroups　by　a　spacer　group.　By　this　way　the　separation　between　the　polar　headgroups　within　gemini　surfactants　is　strongly　decreased　when　they　aggregate　and　thus　the　surface　activity　is　greatly　enhanced.　Introduction　of　gemini　surfactants　is　a　breakthrough　in　concept　compared　with　general　tests　in　enhancing　surface　activity,　for　example,　addition　of　salt,　increasing　temperature　or　mixing　anionic/cationic　surfactants.　Therefore　gemini　surfactants　were　reputed　as　a　new　generation　of　surfactants.