Fiber-reinforced hydrogel drop impacts

Hydrogels are prevalent across a variety of commercial sectors including biomedical and agricultural industries. The deformation characteristics are pivotal for 3D printing and scaffolding which hydrogels are used for, yet the mechanism behind how hydrogels resist applied forces especially when they are reinforced with fibers is not clear in the literature. For example, recent studies of impacting hydrogels have shown how the hydrogel deformation leads to non-trivial delay in the contact (i.e. air entrainment) at lower Weber numbers and the importance of poroelasticity in the coupled fluid flow and elastic deformation of the hydrogels at higher Weber numbers. In this work, we show how cellulose-reinforced hydrogel drops deform from impact as well as the force response due to the impacts utilizing high-speed imaging and a pressure transducer. We have sought to delineate the regimes which fibers have a weak versus strong influence on the deformation dynamics.