Molecular interactions in bacterial cellulose composites studied by 1D FT-IR and dynamic 2D FT-IR spectroscopy.

Specific strain-induced orientation and interactions in three Acetobacter cellulose composites: cellulose (C), cellulose/pectin (CP) and cellulose/xyloglucan (CXG) were characterized by FT-IR and dynamic 2D FT-IR spectroscopies. On the molecular level, the reorientation of the cellulose fibrils occurred in the direction of the applied mechanical strain. The cellulose-network reorientation depends on the composition of the matrix, including the water content, which lubricates the motion of macromolecules in the network. At the submolecular level, dynamic 2D FT-IR data suggested that there was no interaction between cellulose and pectin in CP and that they responded independently to a small amplitude strain, while in CXG, cellulose and xyloglucan were uniformly strained along the sample length.