Figure 4. Microgel beads gap height
To estimate the gap height (hG) of the microgel layer in different pH conditions,we immers the MEMs in the adecuate liquid,
we choose a line segment crossing a bead with a relatively large spacing between neighboring beads,since the finite AFM 
tip size does not allow measurement of the gap between closely packed beads. By carefully choosing the line, we ensure 
that it crosses the apex of the bead to accurately measure its height. 