Deposition Mechanisms in Layer-by-Layer or Step-by-Step Deposition Methods: From Elastic and Impermeable Films to Soft Membranes with Ion Exchange Properties

Figure 4

An example of exponential growth followed by a transition to linear growth for PEI-(PGA-PAH)_n films deposited on silicon by means of alternated spray deposition (5s per deposition and buffer rinse step). The inset shows the thickness increase of the film for the first 22 layer pairs. The following function has been fitted to the data: 𝑑=2+9.52×exp(0.13×𝑛), where 𝑑 (nm) and 𝑛 are the film thickness and the number of “layer pairs,” respectively. The slope of the linear growth regime following the first exponential growth is of 17.5 nm per “layer pair”. These data have been plotted from the data of reference [41].