Angle-dependent XPS study of functional group orientation for aminosilicone polymers adsorbed onto cellulose surfaces

Thin layers of aminosilicones were adsorbed onto cellulose surfaces and examined by angle-dependent XPS (ADXPS) to study the orientation of the amino endgroup relative to the main polymer chain. The results indicate a preferential orientation of the amino group away from the air interface. Furthermore, the degree of endgroup depletion at the air interface was dependent on the polymer chain length and the coverage. A model is proposed in which the greatest effect occurs at near-monolayer coverage, with the endgroups adsorbed at the silicone/cellulose interface and the polymer chains forming loops that extend toward the air interface.