Experimental evidence shows significant effect of ionic concentration of aqueous buffers on the membrane stability, for example during electroporation experiments. Also, the lateral diffusion coefficient is sensitive to ionic strength. We study the effect of ionic strength on lipid membrane by modified Pink model, applying Monte Carlo simulations for a lattice of 50 lipid molecules. The study is provided for the model dipalmitoyl-phosphatidylcholine (DPPC) membrane in the gel phase at the fixed value of dielectric constant. The study in the range of 10--3000 mM, shows a decrease of repulsive interactions between polar heads, accompanied with an increase of attracting van der Waals interactions between acyl chains. Additionally, the chains assume more stable conformation with lower conformational energy. Simulations show rising number of standing polar heads, which may indicate better accessibility of ions from the solution to the polar part of the molecules and their consequent binding.

PACS numbers: 87.16.Dg