Cellulose as matrix component of conducting films

Conjugated polymers gain growing importance as conductive materials in industrial applications in various fields of electronic devices. Cellulose with its extraordinary supramolecular structure and material properties can help to awake the possibilities for conducting polymers in interplay of the two materials. The ability of additional derivatization, the stiff and oriented molecular structure and the inherent strength, stability and film-forming properties give cellulose a complementary role to the brittle conjugated polymers, cellulose imparting the features of a stable and robust carrier component. To go forward this way, making a composite out of cellulose and conducting polymers is a prerequisite. Different strategies to form composite materials of non-derivatized cellulose and conductive organic polymers were tested. Significant differences between various mixing strategies as well as between the conducting polymers polyaniline (PAni), polypyrrole (PPy), and polythiophen (PTh) were observed. In situ synthesis of the conducting polymers in cellulose solutions and microcellulose dispersions as well as blending of pre-synthesized conducting polymers in these cellulose systems were tested. Unexpectedly, not homogenous mixtures showed best results in respect to film formation and conductivity, but composites formed by heterogeneous mixtures of the conducting polymers within a cellulose gel. Best results were obtained with finely dispersed PAni. The results support development studies towards circuitry and photo-current systems based on cellulose carriers.