Effects of hydrophobic chain length on temperature dependence of monolayer behavior of ester-type tartaric geminis.
Ester-type tartaric gemini amphiphiles bearing two carboxyl groups and two hydrophobic alkanoyl groups were prepared from L-tartaric acid, and the pressure-area (π-A) isotherms for a series of symmetric tartaric gemini amphiphiles were measured by the conventional film-balance technique. The effects of the length of the hydrophobic alkanoyl chains and of the subphase temperature (T(sub)) on the π-A isotherms for these compounds were examined. As the length of the hydrophobic alkyl chain increased, a more tightly packed monolayer was formed at the air-water interface. The melting temperature (T(m)) of the monolayer on the water surface was evaluated from the subphase temperature (T(sub)) dependence of the monolayer static elasticity ε(s), based on a π-A isotherm. A clear relationship between T(m) and hydrophobic carbon number (n) was observed for 2D monolayers of tartaric geminis on water surfaces, as well as for fatty acids and/or 3D solids.
Department of Chemistry and Materials Technology, Kyoto Institute of Technology, Kyoto, Japan. kawase@chem.kit.ac.jp
Tokuzo
T
Kawase
Isao
I
Saito
Tatsuo
T
Oida
D004952:Esters / Q000737:chemistry*; D005227:Fatty Acids / Q000737:chemistry; D057927:Hydrophobic and Hydrophilic Interactions; D011312:Pressure; D013499:Surface Properties; D013501:Surface-Active Agents / Q000138:chemical synthesis / Q000737:chemistry*; D013644:Tartrates / Q000138:chemical synthesis / Q000737:chemistry*; D013696:Temperature; D044366:Transition Temperature; D014867:Water / Q000737:chemistry
D004952:Esters; D005227:Fatty Acids; D013501:Surface-Active Agents; D013644:Tartrates; D014867:Water