The Improved Redispersibility of Cellulose Nanocrystals Using Hydroxypropyl Cellulose and Structure Color from Redispersed Cellulose Nanocrystals

Cellulose nanocrystals (CNC) have been significantly developed as a building block material for the design of novel functional materials in many fields such as biomedicine, nanotechnology, and materials science due to their excellent optical properties, biocompatibility, and sustainability. Improving the redispersibility of CNC in the sustainable processing of nanocellulose has been a challenge because intense hydrogen bond interaction leads to irreversible aggregation, making CNC difficult to redisperse and increasing the cost of storage and transportation of CNC. Hydroxypropyl cellulose (HPC) is an important hydroxy propylated cellulose ether. As a water-soluble cellulose derivative, HPC has a polyhydroxy structure similar to that of CNC, which leads to good compatibility and high affinity between HPC and CNC. In this work, HPC of different molecular weights was comixed with CNC of different contents, which was then dried using different methods, and the dried samples were redispersed in water. The addition of HPC improved the redispersibility of the CNC. Finally, the redispersed suspension was also redried to form a film, which was found to retain its structure color. These results provide an important avenue for the redispersion of dried CNC and for the development of functional materials from redispersed CNC.