Bacterial cellulose (BC), obtained from fermented food byproducts (Symbiotic Culture of Bacteria and Yeast, and Nata de Coco), was successfully used as a template for the synthesis of a YBa2Cu3O6+δ (YBCO) superconductor. As previous studies have shown, a dry template is needed to ensure the maximum uptake of the precursor solution. BC used is obtained in a wet state; it must be dried before use as a template. A variety of template drying techniques were investigated to assess the efficacy. This included air, oven, freeze, and solvent exchange drying. Among these, freeze-drying proved to be the most effective method as it best preserved the porous internal structure of the template. The addition of ethylenediaminetetraacetic acid (EDTA), a polychelating acid, also had a beneficial effect on the synthesis, improving both phase purity and the contribution of the superconducting phase. Waste-derived BC was shown to be a suitable substrate for the sol–gel synthesis of cuprate superconductors, providing an alternative to the ionic-liquid/nanocellulose-based approach used previously.
Uszko et al. (Thu,) studied this question.