Localization and attempted quantification of various functional groups on pulpwood fibres

The distribution of different free chemical functional groups on wood and pulp fibres has been determined by means of atomic force microscopy (AFM) with chemically modified tips. Because these functional groups show a higher affinity to similar groups on the substrate surface during scanning, AFM images determined with an additional digital pulsed-force mode (DPFM) controller allow the distribution of the chemical components to be imaged and to a degree also to be quantified. The investigated tip coatings showed a different sensitivity towards the major chemical components present in wood fibres, determined on spin-coated films and on wood fibres. A clear distinction between cellulose and lignin was possible in both cases. This technique could therefore be used to differentiate between cellulose and lignin present on pulp fibre surfaces and confirm the successful removal of lignin by pulping.