Controllable Construction of Temperature-Sensitive Supramolecular Hydrogel Based on Cellulose and Cyclodextrin

Abstract

In temperature sensitive hydrogels, the swelling degree or light transmittance of the gel itself changes with variations in ambient temperature, prompting its wide application in controlled drug release, tissue engineering, and material separation. Considering the amphiphilic structure of β-cyclodextrin (β-CD), a cellulose-based supramolecular hydrogel with superior temperature sensitivity was synthesized based on a combination of cellulose and β-CD as well as the host–guest interaction between β-CD and polypropylene glycol (PPG). In the one-pot tandem reaction process, chemical grafting of β-CD on cellulose and the inclusion complexation of β-CD with PPG were performed simultaneously in a NaOH/urea/water system. The obtained supramolecular hydrogel had a lower critical solution temperature (LCST) of 34 °C. There existed covalent bonding between the cellulose and β-CD, host–guest complexation between the β-CD and PPG, and hydrogen bonding and hydrophobic interactions between the components in the network structure of the supramolecular hydrogel. The combination of various covalent and non-covalent bonds endowed the resulting supramolecular hydrogel with good internal network structure stability and thermal stability, as well as sensitive temperature responsiveness within a certain range—implying its potential as a smart material in the fields of medicine, biology, and textiles. This work is expected to bring new strategies for the fabrication of cellulose-based thermosensitive materials, benefitting the high-value utilization of cellulose.