pH-Regulated Single and Double Charge Inversions on PEI-Coated Surfaces

Area of Science:

• Surface chemistry
• Materials science
• Nanotechnology

Background:

• Polyethylenimine (PEI)-coated surfaces are vital in biomaterials and nanomaterials due to pH-regulated charge inversions.
• While single charge inversion is well-studied, double charge inversion on PEI surfaces is less understood.

Purpose of the Study:

• To systematically investigate the pH-regulated charge density of PEI-coated surfaces using molecular theory.
• To elucidate the factors governing single versus double charge inversion and the reasons for the rarity of double inversion.

Main Methods:

• Molecular theory simulations were employed to study PEI-coated surfaces.
• Systematic analysis of pH-regulated charge density was performed.

Main Results:

• The occurrence of single or double charge inversion is determined by PEI affinity to the surface and the bare surface charge density.
• The parameter space for double charge inversion is significantly smaller than for single charge inversion.
• Solution conditions critically influence the observed charge inversions.

Conclusions:

• The findings provide a theoretical basis for understanding charge inversion phenomena on PEI-coated surfaces.
• This work offers guidelines for selecting materials and optimizing PEI solution parameters for designing advanced PEI-coated surfaces.
• The study enhances the potential for developing multifunctional nanomaterials utilizing controlled charge inversion.