Vesicles　were　formed　in　aqueous　mixtures　of　gemini　anionic　surfactant,　O,O′-bis(sodium　2-alkylcarboxylate)-p-dibenzenediol　(referred　to　as　Cmϕ2Cm,　m　=　10,　12),　and　single-chain　cationic　surfactant,　alkyltrimethylammonium　bromides　CnNBr　(n　=　8,　10,　12).　This　was　confirmed　by　measurements　of　solution　turbidity,　dynamic　light　scattering　(DLS)　and　freeze-fractured　TEM.　The　improvement　of　the　Cmϕ2Cm　molecular　geometry　by　CnNBr　was　considered　to　have　been　due　to　vesicle　formation.　As　the　temperature　was　raised,　these　vesicles　were　found　to　associate　together　and　DLS　measurements　showed　a　rapid　increase　of　the　aggregate　size　at　the　critical　temperature　Tc.　The　mechanism　of　vesicle　aggregation　was　assumed　to　be　due　to　the　temperature-induced　configuration　transition　of　a　few　Cmϕ2Cm　molecules　in　the　vesicles　from　cis-　into　trans-form.　Thus,　a　few　tails　of　Cmϕ2Cm　stretched　toward　the　solution.　When　the　vesicles　approached,　these　projecting　tails　interacted　hydrophobically,　thereby　non-covalently　attaching　one　vesicle　to　another.　This　should　benefit　from　the　special　molecular　structure　of　Cmϕ2Cm　with　a　long,　rigid　spacer.　©　2015,　Springer-Verlag　Berlin　Heidelberg.