Supramolecular design of cellulose hydrogel beads

In the present study, we report the supramolecular design of cellulose-sulfonate hydrogel beads by blending water soluble sodium cellulose ethyl sulfonate (CES) with the pretreated cellulose in sodium hydroxide-ureawater solvent system at –6 °C followed by coagulation in the 2M sulfuric acid system. The increasing of CES amount from 10% to 90% had a substantial effect on the viscosity and storage (G') and loss (G") moduli of the blended solutions. The CES concentration up to 50% in blends led to the formation of physically stable hydrogels after coagulation in acidic medium at pH-1 and showed the retention of nearly the same CES concentration at pH-6 after continuous water washings. The increased sulfonate content also enhanced the water holding capacity and internal porosity of the beads. Both ATR-FTIR and Raman spectrometry were used for the qualitative determination of sulfonate groups and SEM-EDX was used for the quantitative estimation in dried beads. In this research, we have established a correlation between the presence of anionic charge in the polysaccharide blend and stability of the prepared hydrogel beads. Hence our research provides a systematic methodology to design functional, highly porous cellulose hydrogels having the potential to be tested further in biomedical and healthcare applications.