The first enhanced sampling strategy consists on stratifying the relevant range of the collective variable, e.g. 0 ≤ ξ ≤ r cut , where r cut is the cutoff distance from which the free energy no longer changes. By confining the region of phase space that can be examined to a small range of the colvar, a more comprehensive spectrum of conformations can be developed at the same computational expense. In this work, the stratification scheme is applied such that the range of collective variables is divided in windows that are 3 Å wide. The initial configurations for each window are obtained by using steered molecular dynamics, where the polar head-group is pushed towards a prescribed distance with respect to the deposit.