The procedure for isolating of CNCH2SO4 was adapted from  with slight modification. Briefly, 1 g of cellulose material was dispersed in 100 mL deionized water through continuous mechanical stirring before the dropwise addition of 60 mL concentrated H2SO4 under an ice bath. This was to minimize a sudden temperature spike due to the exothermic reaction caused by the ion interaction between water and sulfuric acid. The suspension then heating up to 45 °C for 135 min. The reaction was terminated by diluting it with 10-fold cold water to avoid crystallization (iced water can be used to minimize dilution water usage while effectively terminating the hydrolysis reaction). The diluted suspension was centrifuged repeatedly to get the precipitate while removed the excess acid simultaneously by washing with deionized water. The supernatant was decanted off; fresh deionized water was added to the solids and mixed it well. This washing and centrifuging procedure were repeated until the supernatant was turbid, suggesting that CNCH2SO4 were being dispersed in solution. The turbid supernatant and settled solids were then mixed together and this slurry dialyzed against distilled water for 3–4 days until a constant pH was achieved, and freeze-dried to yield a white sulfate ester nanocellulose product. The dried product was stored in a vacuum for further product characterization.