Karl Franzens University Graz
Graz University of Technology
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Karl Franzens University Graz | Graz University of Technology | |
Atomic-force microscopy based exploration of cellulose fibers and their bonds. Paper is a versatile material that has been used by mankind for centuries, mainly for the exchange of information or for protecting and storing goods. During the past seven years, Styrian researchers employed modern surface science methods within a Christian Doppler Laboratory located at Graz University of Technology to obtain new insights in the bonding of cellulose fibers within a network called paper. In the talk, I will demonstrate how we adapted in the Scanning Probe Microscopy Group in Leoben atomic force microscopy (AFM) - originally dedicated to resolve smooth and clean insulating surfaces on the atomic scale - not only to image the morphology of - curved - cellulose fibers in dry and wet stage [1,2] but indeed to determine the mechanical properties of individual fibers [3] and their bonds [4]. The combination of recording force distance curves in the AFM until the bond between two paper fibers breaks and imaging the formerly bonded area revealed new insights into the bonding mechanisms [5]. In particular, it could be shown that mechanical interlocking of single fibrils or fibril bundles, which act as bridging elements between the fibers, plays a crucial role in fiber bonding. For packaging paper fabricated of highly refined pulp, this mechanism boosts the bond energy by a factor of two helping to reduce materials and energy input in a billion dollar industries. |