We present the results of CGMD simulation di-bloc copolymer membranes using a charge free model.  Specifically, we were able to reproduce many phases of the PAA-PBA  diblock copolymer, Ca(+2) and water systems as a function of pH and calcium concentration with short range LJ type potentials.  The morphologies observed range from bilayers to cylinders to spherical micelles.  Our model is able to reproduce different morphologies due to pH and with or without the addition of Ca(2+) as well as the lateral phase segregation and the domain registration observed in neutral and charged diblock copolymer mixtures. The results suggest that the overall effect of charges is a local structural rearrangement that renormalizes the steric repulsion between the headgroups. This simple model which is devoid of charges is able to reproduce the complex phase diagram and can be used to investigate collective phenomena in these charged systems such as domain formation and registration or co-localization of lipid rafts across bilayer leaflets. 

Domain registration in membranes: Evidence from coarse grained molecular dyamincs

244th National Meeting (2012)

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