Chemical and Structural Properties of Polyethyleneimine Film Coated on a SiO₂ Substrate in Different Concentrations

Abstract

Angle-resolved X-ray photoelectron spectroscopy (AR-XPS) and atomic force microscopy (AFM) were employed to investigate the detailed surface bonding structure and morphology of polyethyleneimine (PEI) layers coated on a SiO 2 substrate in concentrations of 0.5 10.0 mass%. With an increase in the PEI concentration, the CN bonds corresponding to the imine group (NH) became dominant in the PEI layers, implying a characteristic feature to verify the immobilization of PEI on the SiO 2 surface. The thickness of PEI layer calculated using AR-XPS gradually increased with increasing PEI concentration up to a maximum 5 mass%, above which it became saturated. AFM results showed that an increase in PEI concentration led to a decrease in the root mean square (RMS) roughness of PEI layers. Such a saturation tendency of PEI thickness combined with the strongly dependence of the surface morphology behavior of PEI layers on the PEI concentration indicated that SiO 2 surface was fully covered by monolayer PEI with a smooth surface morphology at PEI concentration in excess of 5 mass%.

Layer‐by‐layer fabrication of nacre inspired epoxy/MMT multilayered composites

“…The appearance of CN corresponds to CN bonds in PEI, clay modified with APTMS and covalent linkage between epoxy and amine. These assignments are in well agreement with the literature …”

Soft cellulose II nanospheres: sol–gel behaviour, swelling and material synthesis

“…The QCM crystals were coated beforehand with a polyethyleneimine monolayer. The effect of this layer on the QCM experiment can be neglected due to its low thickness of 0.6 nm 37 . NPan and CNF were adsorbed during the QCM experiment onto the polyethyleneimine-coated QCM crystals through electrostatic interactions ( Figure S5).…”

Increase in Interfacial Adhesion and Electrochemical Charge Storage Capacity of Polypyrrole on Au Electrodes Using Polyethyleneimine

“…The amount was 0.64 ± 0.252 μg/cm 2 , indicating that a PEI layer of 6.4 nm thickness adhered to the Au surface, assuming its density to be 1.03 g/cm 3 16 . This thickness is much greater than that of a PEI monolayer coating (~0.6 nm) 14 , which suggests aggregation of the PEI layer. Scanning electron microscopy (SEM) confirmed that the O 2 plasma-treated Au electrode was covered with a non-uniform coating of PEI.…”

“…The slight negative shift of the Au 4 f peaks indicated that the gold surface was reduced by the non-protonated amino groups of PEI 13 . The positive shift of the C = O peak after PEI adsorption indicates the interactions between C = O and the positively charged amino groups of PEI 14,15 . These results show that the PEI layer interacts with both the carbonyl groups present on the treated surface and the Au metal surface.

Figure 2XPS spectra of ( a ) N 1 s, ( b ) C 1 s of a PEI-O 2 Au electrode, and ( c ) C 1 s of an O 2 Au electrode.

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“…After plasma treatment on Au surface, gold oxide is formed, carbon contamination is removed, and polar groups (e.g. CO) appear 14,15 . It has been reported that gold oxide and the sites of polar groups are non-uniform and discontinuous on the surface 17 .…”