Brushes of flexible, semiflexible and rodlike diblock polyampholytes: Molecular dynamics simulation and scaling analysis

Planar brushes of flexible, semiflexible and rodlike diblock polyampholytes are studied using molecular dynamics simulations and scaling analysis in a wide range of the grafting density. Simulations show linear dependence of the average thickness on the grafting density for all the brushes regardless of their different equilibrium conformations and different flexibility of anchored chains. Slopes of fitted lines to the average thickness of the brushes of semiflexible and rodlike polyampholytes versus the grafting density are approximately the same and differ considerably from that of the brush of flexible chains. The average thickness of the brush of diblock polyampholytes is also obtained as a function of the grafting density using a simple scaling analysis which is in good agreement with the results of our simulations.