Figure 4
Gradient isosurfaces (s = 0.5 au) for (a) NR-PAAM/PA/PDA hydrogel, (b) MB-PAAM/PA/PDA hydrogel, (c) MV-PAAM/PA/PDA hydrogel and (d) YMB-PAAM/PA/PDA hydrogel through VMD (Visual Molecular Dynamics)60, respectively. The surfaces are colored on a blue-green-red scale according to values of sign(λ2)ρ, ranging from −0.04 to 0.02 au. Blue indicates strong attractive interactions, and red indicates strong nonbound overlap. Large and negative values of sign(λ 2)ρ indicate attractive interactions (such as dipole-dipole or hydrogen bonding, blue color), while large and positive values of sign(λ 2)ρ represent nonbonding (red color). The values of sign(λ 2)ρ near zero indicate van der Waals interactions, such as π-π stacking effect.
