Toughened Hydrogels through UV Grafting of Cellulose Nanofibers

The purpose of this research is to obtain toughened hydrogels by tailoring the interfacial interactions between cellulose nanofibers (CNFs) and a polymer matrix. To this end, a polymer matrix is grafted from the surfaces of CNFs to form a one-component nanocomposite hydrogel via a novel and green method, i.e., UV irradiation in the absence of an initiator. As a result, the toughness of this hydrogel is highly improved by 140.6% in contrast to the one with the same composition but an independent CNF–matrix architecture. We also find that hardwood-based CNFs result in more stretchable but softer hydrogels in contrast to softwood-based CNFs. It is revealed that the surface chemistry of CNFs plays an important role in fabricating such nanocomposites. We believe that UV grafting of CNFs may help fabricate various kinds of nanocomposites with good interfacial compatibility and interesting features.