Regulation of the micromorphology and performance of cellulose hydrogels by silk nanofibers

Silk nanofibers (SNFs) obtained by dilute alkali treatment were dispersed in a NaOH/urea system at room temperature, while cellulose was dissolved in a NaOH/urea system by freezing-thawing treatment. The SNFs and cellulose were composited by mixing and standing, and the cellulose was found to regenerate by adhering to the SNFs. Composite hydrogels with good mechanical properties were further prepared by acetic acid gas phase coagulation. Using composite hydrogels as templates, Cu2+ was in situ synthesized into homogeneous copper oxide (CuO) nanoparticles by a simple and rapid method. Obviously, the addition of SNFs not only enhanced the mechanical properties of the hydrogels but also affected the micromorphologies of the hydrogels and the morphology of the synthesized CuO nanoparticles. The composite hydrogels with CuO nanoparticles synthesized in situ showed potential photocatalytic activity for the degradation of methylene blue dye. The degradation rate of methylene blue dye by the SNF/cellulose/CuO nanocomposite hydrogel was 90.2 %, which was obviously higher than that of the cellulose/CuO composite hydrogel. The results proved the regulation of the micromorphology and performance of the cellulose hydrogel by SNFs.