Facile synthesis of self-dispersed β-cyclodextrin-coupled cellulose microgel for sustained release of vanillin

A self-dispersed beta-cyclodextrin-coupled cellulose (beta-CD-Cel) microgel was firstly synthesized via chemically coupling cellulose and beta-CD in NaOH/urea aqueous solution. Following, after encapsulating the hydrophobic vanillin molecules into the cavities of beta-CD-Cel microgel through host-guest interaction, cellulose-based long-lasting fragrance-released complex was obtained. beta-CD was mainly bonded onto the hydroxyl groups at C6 in the AGU units of cellulose, and about 0.5 beta-CD molecule were introduced into the AGU unit when cellulose skeleton contained the fl -CD content of 19.33%. FTIR, H-1 NMR, XRD, and UV-Vis provided evidences for the encapsu-lation of vanillin in the cavity of beta-CD-Cel, and the encapsulating efficiency of vanillin for the beta-CD-Cel inclusion complex was upped to 86.9%, which exceeded that of single beta-CD small molecule encapsulating fragrance. Benefiting from the reversible host-guest interaction between beta-CD and vanillin molecule, the continuous fragrance release time could exceed 196 h, and the sustained release behavior of beta-CD-Cel complex could be adjusted by temperature. Also, the fragrance-released beta-CD-Cel composite film showed high transparency, strong water resistance, and good flexibility. The vanillin retention of the composite film can keep 40% after soaking in ethanol solution for 96 h. This study will provide a new approach for the development of biomass functional coating.

Automated summary

A self-dispersed beta-cyclodextrin-coupled cellulose microgel was synthesized, and vanillin molecules were encapsulated into the microgel through host-guest interaction, resulting in a cellulose-based long-lasting fragrance-released complex. The complex exhibited adjustable sustained release behavior and good physical properties, making it a promising material for biomass functional coating.