Date of Award

Summer 1989

Degree Type

Thesis - Restricted

Degree Name

Master of Science (MS)



First Advisor

Collins, Joseph M.

Second Advisor

Feldott, Jeanette

Third Advisor

Mendelson, Kenneth S.


The influence of low molar solutions of CaCl2 on the phase transitions of saturated chain phospholipids have been examined by using calorimetry and characterized by X-ray diffraction techniques. We analyzed the thermodynamic properties of DPPC, DLPE and, DPPG dispersed in water and CaCl2 solutions. In this work involving phospholipids having different head groups, we had to induce the subgel phase in order to make meaningful comparisons between these lipids. We conclude that all the three lipids are affected by Ca2+ in varying degrees. The ca2+ interaction with DPPC causes a reduction in the transition enthalpy between the subgel to gel transition with increasing CaCl2 concentration, whereas the interaction with DPPG produces a profound effect; eliminating the sub and pre-transitions and raising the main transition temperature by as much as 40°C. The Ca2+ interaction with DLPE appears to be biphasic. The degree of ca2+ binding to these phospholipids increases in the following sequence: DLPE < DPPC < DPPG.