Elastic property of organized lipid assembly — Effect of water incorporation and chain melting

The effect of electric field on the capacitance of lipid-water dispersion properly aligned on polyvinyl alcohol coated glass electrodes, shows a transition pattern where a rapid change in orientation of the organized lipid assembly takes place for an electric field above a threshold value (V_th), similar to that of Freedericksz’s transition as observed in the case of thermotropic liquid crystals. The splay elastic constant, k₁₁ and the bend elastic constant, k₃₃ have been calculated from the measured values of capacitance of the cell below and above V_th. These values change by several orders of magnitude depending upon the presence of water as well as temperature of chain melting of the lipid moiety.