Attractive double-layer forces and charge regulation upon interaction between electrografted amine layers and silica

• Amine functionalities have been introduced on glassy carbon surfaces through electrografting of 4-(2-aminoethyl)benzenediazonium tetrafluoroborate. The grafted layers were characterized by ellipsometry and by nanomechanical mapping in air and aqueous solutions using the atomic force microscopy PeakForce QNM mode. The layer was found to be 2.5. nm thick with low roughness, comparable to that of the glassy carbon substrate. However, small semi-spherical features were observed in the topographical image, indicating a clustering of the grafted amine compound. The nanomechanical mapping also demonstrated some swelling of the layer in water and pointed toward an important contribution of electrostatic interactions for the tip-surface adhesion. The forces between an aminated glassy carbon surface and a μm-sized silica particle in aqueous solutions were measured at different ionic strength and pH-values. The results demonstrate that an attractive double-layer force predominates at large separations, and that the surface charge densities increase as the separation between the surfaces decreases. The degree of charge regulation on the aminated glassy carbon is significant. The relatively low surface charge density of the aminated glassy carbon is attributed to significant incorporation of counterions in the water-rich grafted layer.

Ämnesord

NATURVETENSKAP  -- Kemi -- Annan kemi (hsv//swe)

NATURAL SCIENCES  -- Chemical Sciences -- Other Chemistry Topics (hsv//eng)

Nyckelord

AFM

Double-layer force

Electrografting

Phenylethylamine

Surface charge

Surface potential

Amine compounds

Amine functionality

Benzenediazonium tetrafluoroborate

Carbon substrates

Charge regulation

Counterions

Double layer force

Glassy carbon surfaces

Grafted layers

Nanomechanical mappings

pH value

Phenylethylamines

Silica particles

Topographical images

Atomic force microscopy

Grafting (chemical)

Ionic strength

Organic compounds

Separation

Silica

Solutions

Glassy carbon

4 (aminoethyl)benzenediazonium tetrafluoroborate

amine

carbon

imidazole derivative

silicon dioxide

unclassified drug

water

adhesion

aqueous solution

article

chemical bond

chemical structure

dielectric constant

electrochemical analysis

electrode

electron transport

ellipsometry

force

molecular mechanics

pH

priority journal

static electricity

thickness

Publikations- och innehållstyp

ref (ämneskategori)

art (ämneskategori)