Nanomechanical Characterization of Functional Cellulosic Fibres

为了开发电子学、微流变学或诊断学等领域的功能纸，预测单根纤维经过加工和改性后的性能是必不可少的。纤维的特性在纤维内部和纤维之间也是不同的。因此，该项目的目标是以高空间分辨率表征功能性纤维和纤维接头的机械参数(弯曲硬度和拉伸强度)以及湿度对这些参数的影响。由于原子力显微镜(AFM)具有良好的空间和力的分辨率，因此原子力显微镜(AFM)将成为表征纤维的主要实验工具。此外，还将利用共聚焦拉曼光谱进行化学计量学作图，这将有助于直接绘制聚合物涂层的图谱。因此，将确定功能性聚合物在羊毛和纤维上的分布，并评估涂层对润湿性和吸水率的影响，从而评估机械性能。利用原子力显微镜对力学性能进行纳米尺度的表征，可以在非常小的范围内可视化聚合物在纤维表面和靠近表面的整体上的分布，并以非常高的灵敏度验证力学性能的变化，如刚性。图像处理和与光学、电子和拉曼显微镜的关联可以得到关于聚合物在羊毛中的分布及其对机械性能的影响的详细图像。更好地了解当地的机械性能和吸水的纳米机械图像有助于改进该联盟所使用的造纸和改性的方法和过程，并为数值模拟提供输入参数。作为一个附加值，该联盟的协同作用将有助于更详细地了解功能性文件中的吸水率以及湿度对羊毛机械性能的影响。

For the development of functional papers in areas such as electronics, microfluidics or diagnostics it is essential to predict the properties of single fibres after processing and modification. The characteristics of the fibres vary within a fibre and also between the fibres. The objective of this project is thus to characterize functional fibres and fibre joints with respect to their mechanical parameters (flexural stiffness and tensile strength) and the impact of humidity on these parameters with high spatial resolution. This, also the variability of these parameters on individual fibres and between different fibres will be assessed.Because of its excellent spatial and force resolution, the atomic force microscope (AFM) will be the main experimental tool for the characterization of the cellulosic fibres. In addition chemometric mapping will be carried out by using confocal Raman spectroscopy, which will help to directly map polymer coatings. Thus, the distribution of the functional polymer within the fleece and on the fibres will be determined and the impact of the coating on wetting and water uptake and thus the mechanical properties will be assessed. The nanoscale characterization of mechanical properties with the AFM allows one visualize the distribution of the polymer on the fibre surface and bulk near the surface on a very small scale and to verify changes in the mechanical properties such as stiffness with very high sensitivity. Image processing and correlation with light, electron and Raman microscopy yield a detailed picture about the distribution of the polymer in the fleece and its impact on the mechanical properties.A better knowledge of the local mechanical properties and the nanomechanical picture of the water uptake helps to improve the methods and processes for paper making and modification which are used in this consortium and provides input parameters for numerical modelling. As an added value the synergies in this consortium will thus contribute to a more detailed picture of water uptake in functional papers and the impact of humidity on the mechanical properties of the fleece.